 



 

 

 

       

     

  

   



     

    

  

 

                                                                                                                                                                                                                                                                                                                                                               

      

    

     

    



        

  

Question: What is the smallest sized cube that can be made out of LEGO bricks?

   

   

 Construction Note: Use normal plates when you don’t need the through holes. Save the Technic plates for where they are needed.

Question: What is the smallest sized cube that can be made out of bricks and plates?

         



            

   

                                  

  

          

        



   

       

    

   

                 



Links: Jim Hughes maintains Technica, a beautiful website that has a complete Technic parts registry with pictures and an interesting history of LEGO. His URL is w3.one.net/~hughesj/technica/technica.html.

      

  

  

   

   

        

   



     

    

Question: What is the shortest stack of beams (no plates allowed) that will align with holes in a vertical beam?

Construction Note: The two assemblies below are the same height, but the one on the right allows for locking the beam at an intermediate point and has better spacing for vertical meshing of LEGO gears.

     



   

   

    

  

        C = A  + B                          

     

      



 





       

            

     

   

        

      

           

 

           

 

  

                            

  Construction Notes: Gear spacing of two or three studs provides the maximum number of gear combinations. Two stud spacing also works well in vertical layouts.      

                

     

    

 



       

 



                       

            

      

     

                

     

        

    

  

  

     

   

   

 

         

 

                    

           

        

       

Links: Ted Cochran has a nice treatment of gear ratios with Minnesota FLL examples at www.hightechkids.org/fll/coaching/Gears/gears.htm.

     

  



   

     

              



    

  

       

  

   

      

                



  

                    

  

    



         

Links: How Stuff Works, one of the best sites on the web, has a wonderful article about gears, gear ratios, torque, and speed. Check it out at “www.howstuffworks.lycozone.com”.

    

   

   

             

     

        

Question: For the example above, what would the gear ratio be if the 8 tooth gears were replaced with 24 tooth gears?               

   



      

      

  

     

       

       

      

   

          



    



Question: A wheel made out of bevel gears would not have much traction. For what applications could this be a benefit?       

     

    

   

   

Construction Note: Be careful when constructing a threaded rod out of worm gears. You can put two worm gears on an axle in four different ways, but only one results in a continuous thread.

 

       

       

      

    

 

   

     

        

        

            

     

       

Question: What would happen if a second ratchet was added to prevent the left axle from turning clockwise?

       

     

      

     

         

                   

                             

      

    



Question: How else can we increase the friction between the pulleys and the belt?

  

  Construction Notes: The tank tread and sprocket can be used like a pulley and belt system. The tread’s teeth prevent slipping even if a large torque is applied to the sprocket.     

    

    

 

  



      

    

   

                   

    

    

 

  

     

   

      

     

       



  

    

  

 

 

  

 

                I think I’m OK

    

     

  Wow!!!



Question: For the example above, what would the travel speed be if we changed the gear ratio by putting the 8 tooth gear on the motor and the 24 tooth crown gear on the axle?

     

  



 



     

            Weak!!!

     

Question: If big wheels are less efficient for towing, why do tractors have big wheels?

       

    

   



 

     

     

     

   

      

  

     

     

      

 

   



   

    

 

 

      

Principia     

      

     

         

 

        

       

Question: What else can be done to prevent wheelies besides moving the CG or the wheels?

         

      

      

        

                       

              

     

 

         

            



    

Question: What would the table entry look like for the fully supported wheel assembly shown in Figure 3-12?

  

       

     

     Construction Note: When building your robot, remember that you will have to occasionally remove the RCX to replace the batteries. Design accordingly.



    

        

      

Construction Note: Whenever it is turned on, the RCX is receptive to messages coming in on its infrared serial port. With all the activity and congestion at competitions, it is quite possible that another team could unintentionally overwrite the programs stored in your RCX. Care should be taken to block the IR port when not in use.

                

 

      



    

          

   

     



     



     

  

     

 

    

 

 

      

     

      

       

      

   



     



      



 

      

   

      

      



       

          

    

       



      

      

     

     

     

     

Question: What is the resolution of the rotation sensor in Figure 4-16?         



  

     

           

             

               

        

        

    

       

                                                                 

     

     

  



         

      

       

  

     

  

                   

    

 Blue

White

Red Green

        

Question: In a dark room, what color do you see when shining the light sensor’s red LED light on a yellow LEGO brick?        

 

      

 

   l d  

  =     

l d 

             

      

         

         



     

  

    

      

     

      



     

    

     

        

            

     

Question: In the ’01 FLL challenge “Volcano Panic,” a blue tape line was used to mark the edge of the ocean. The intersection of the blue

 line with one of the many black lines on the table was a useful navigation landmark. Many teams had a hard time finding the blue line. What was the likely source of their problem, and how could they have improved their chances?

                                                                                                                                    

                



      

          

   

 

  

      

         

      

       

       

           

       

     

    

      

Question: What is the resolution of the homemade rotation sensor in Figure 4-28?

       

   

     

     

       

                     

   

          

      

      

     

         

        

        



  

                        

        

        

     

 Question: Drawing on your shopping cart experience, how can you minimize the caster steer effect?

        

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         

      

 

     

                 



  

  

 

      

  

    

    

  

            

 

 





       

       

         

     



 

      

        

     

   

      

      

   

      

Question: What other LEGO parts could be used to design a slip limiting clutch?

    

      

Question: Some vehicles have a button or lever in the passenger compartment for locking and unlocking the differential. Can you think of a scheme where the RCX could lock and unlock our LEGO implementation?

      

    

        

        

     

    

 

         

 

       

  

 

      

   

            

 





   

   

    

      

      

     

 

     

 

 

  

       

