Fabulous Robots with Pre-Fab Parts!
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Tune in each month for a heads-up on where to get all of your “robotics resources” for the best prices! Fabulous Robots With Pre-Fab Parts! wenty five years ago, if you want- pre-fab construction kits that are module, sensors, and rechargeable Ted a robot you built it from scratch. available, and why such a kit may be batteries. The Vex is the de facto stan- Out to the garage you’d go, with just what you’re looking for if you’re dard kit of parts for the US FIRST Vex sheet metal, wood, and plastic bits in wanting to experiment with robotics. Challenge robotics competition, open hand. You’d cut, drill, sweat, and in the to high school students. Participants end you’d have a functional but Vex Robotics form teams who compete with one perhaps amateur-looking robot to Design System another in building and programming a show to your friends and family. And robot to perform a specific task. that would be just for the mechanical The Vex system is based around body. The electronics and brain would the Erector set style of pre-drilled LEGO Mindstorms be a project for the next year — if you stamped metal girders and connector made the effort at all. pieces. To build a robot, you fasten the Now in its second incarnation as Starting about 10-15 years ago, a girders and other parts together using the NXT, LEGO continues as a favorite few enterprising mail order businesses machine screws and nuts. What makes robot construction set in the home and — such as Solarbotics and Lynxmotion Vex different than the Erector set you school. NXT sets combine specially- — began offering robot construction can buy at the toy store is the collec- made electronic components with tra- kits. You could bypass the mechanical tion of parts specially designed for ditional (and some not-so-traditional) construction phase, and go straight to small robotics. It comes with two types LEGO building blocks. the electronics, programming, or even of motors — servo and continuous At the center of the NXT system play phase! The kits were special- rotation gear head — made to fit the is the NXT controller — a second- purpose, designed to construct a single girder construction of the system. To generation microcontroller that sup- version of the robot. To this day, there these motors you can attach a variety ports up to three motors and up to are still plenty of pre-made kits that of mechanical parts, such as wheels, four sensors and other inputs. Like make it easy to build a robot, letting gears, and even tank-type treads. the RIS controller in the original you concentrate on the other aspects Once upon a time, Vex was sold Mindstorms set, the NXT provides that you may find more enjoyable. exclusively by RadioShack, so it was visual feedback using an LCD display, Now, the latest trend in amateur widely and easily available. Alas, that and receives its programming from a robot construction is prefabricated company had rolled back its inventory PC (in the case of the NXT, the connect components that allow you to build a in hobbyist electronics parts, and no is via USB; early RIS controllers used variety of designs, all from a single kit longer distributes the sets. You can still infrared communications). Once it has of parts. The idea is hardly new — for get Vex via mail order from the manu- received its programming, the NXT is decades, kids have been building things facturer’s website at vexlabs.com. self-contained and operates by itself. with Erector and LEGO parts, even They sell a starter kit, as well as NXT connects to a wide variety of Lincoln Logs. While the idea of mixing separate components. Need an extra motors and sensors, which either come and matching components to build set of wheels? No problem! They are with the basic Mindstorms NXT kit, or custom designs is old-hat, only recently available separately, along with various are available separately. Basic touch, has the concept come to the field of packages of extra girders, nuts, bolts, light, and sound modules provide basic educational and amateur robotics. and other hardware. sensory feedback, and ultrasonic and In this month’s column, we’ll take The $300 Vex starter kit also accelerometer sensors give the NXT the a closer look at some of the robot includes a programmable electronics ability to judge distances and even tilt. 72 SERVO 05.2007 The motors on the NXT are enhanced bipedal robot, the body for a four- and (www.robotis.com). I’ve included and provide built-in encoders, which six-legged walking robot, and parts to several North American dealers in the count the revolutions of the drive shaft make a sci-fi looking robot hand. Sources section that follows. as the robot rolls along the carpet. As pre-fab kits go, the Bioloid is While NXT comes with graphical pro- Robix Rascal relatively inexpensive, especially when gramming software, LEGO also provides you consider it comes with everything an open source firmware API (applica- The Rascal Classroom Robot Set you need to start building, including tion programming interface), so you can from Robix is, as its name the battery pack and the motors. The lift up the hood and work directly with implies, designed for classroom study servos used in the Bioloid are not off- the electronics in the NXT module. of robotics and mechanics. Yes, you the-shelf; in fact, they are proprietary can build several different types of designs that boast upwards of 220 oz- Lynxmotion robots with the Rascal kit, but in torque (at 9.6 volts). They are unlike Servo Erector Set the emphasis is on learning about traditional servos in that they are mechanical design and construction. operated using serial commands. You Lynxmotion was one of the first Rascal parts are relatively simple don’t need or use separate pins on a robotics-specific companies to realize and straightforward, and that’s the microcontroller for each servo; instead, the benefits of producing prefabricated secret to their ingenuity. Kits are all the Bioloid servos are connected to construction parts, allowing builders composed of standard R/C servos and the same serial communications input. the freedom to create custom designs. pre-cut and pre-drilled aluminum angle The Bioloid servos provide torque and Their Servo Erector Set is composed of stock called Rascal Links. The links angular feedback. a variety of stamped aluminum metal come in different lengths. When you consider that a high- brackets that are specially designed to The servos in the Rascal kit are torque standard R/C servo motor costs work with common R/C servo motors. standard R/C unique, and can be about $40, 18 such motors would set By connecting the brackets, chan- commanded using most any serial you back $720. At $899 for the full nels, tubing, and other construction servo controller or microcontroller. A Bioloid kit, you get the equivalent value hardware in various ways, it’s possible controller is included in the Rascal kit, in servos, plus a microcontroller, battery to build two-, four-, six-, and even which is designed to operate up to 32 pack, and construction pieces. Actually, eight-legged walking robots. In similar servos via a USB link to a PC or Mac. this comparison is not accurate, fashion, you can build arms, grippers, Software supplied with the kit provides because traditional analog R/C servos pan/tilt mechanisms, wheeled robots, a programming environment. do not provide the feedback possible and just about anything else that uses with the Bioloid servos, and few standard R/C servos. A page on the Robotis Bioloid are capable of torque much beyond Lynxmotion site provides a long list of 100-110 oz-in. (The 200 oz-in range is illustrated examples of what you can An exciting new entrant into the mostly occupied by digital hobby build using the Servo Erector Set. prefab robot kit arena is the Bioloid, servos, which retail for $75-$125 each.) The component parts of the compa- from Korea-based Robotis. The full The Robotis kit is a great deal now, ny’s Servo Erector Set are wide and Bioloid kit (about $900) comes with and promises plenty of fun. It’s likely varied. Lynxmotion sells some small kits enough parts to — according to the only the first one in a soon-to-be long with parts designed for specific tasks, sales literature — build 26 different line of all-in-one imported kits from like a two- or three-degree-of-freedom robots. No doubt with a bit of creativi- Korea, Japan, and China that are sure leg. Buy four, six, or eight sets to con- ty you could build more, especially if to follow. This is a market that is sure to struct a complete walking robot. Or, you you combine parts from additional kits. catch on. can purchase the individual parts sepa- The full Bioloid kit — called the rately. These parts aren’t inexpensive, Comprehensive Kit — contains a main Ye Olde Standbys but they’re far easier than making them programmable controller, 18 special pro- yourself, and cheaper than if you go to a grammable servo motors, and various Not to be forgotten, these local metal shop for custom-made parts. frame construction pieces. A less expen- construction toys are useful as the Rounding out the Servo Erector sive entry-level kit (about $350) contains framework for DIY robotics. The best Set offerings is a complete collection of the controller, but only four servo part: You probably already have at robot “torsos” or bodies, some made motors and a selection of construction least one set in the back of your closet.