THE MIGHT CONTINUES... AC BALANCE CHARGER Hot on the heels of our wildly popular RDX1 Mini, Hitec is expanding your chargingchar game with the new RDX2. This Mighty Mini featureses dual independent circuitscircuits to chargechar two batteries simultaneously,simultaneously, regardlessregarregardlessegardless of chemistry or capacity.capacity. The sleek, compact design allows easy front-loadingfront-loading convenience, while its powerful output and readilyeadily accessible balancing and XT60 ports make your battery management moremor efficient and effortless. FEATURES • Dual Independent CharChargege Ports • 5-Amp ChargingCharging Output • 100-Watt100-Watt Maximum Output • Charges All Battery Chemistries • Convenient Front-Loading Design Hitec RCD USA, Inc. | 9320 Hazard Way, Suite D, San Diego, CA 92123 | (858) 748-6948 | www.hitecrcd.com SERVO Issue-1.2020 3 Issue-1.2020 VOLUME 18 Departments Subscription Information 06 Mind/Iron SERVO Magazine — 2279 Eagle Glen Parkway #112-481 An Analog Artifact Corona, CA 92883 • (951) 371-8497 Worthy of Your Robotics Call (800) 783-4624 or go to www.servomagazine.com Toolkit Subscribe • Gift • Renewal • Change of Info 26 New Products For more details on subscribing, see our ad on Page 74. 37 The GearBox 72 Advertiser’s Index 73 SERVO Webstore Combat Zone 28 Building a Better Box 30 Stepping Stones — The Story of Thunder Child 33 Bringing About the Apocalypse Page 30 20 Bots in Brief • Armed and Dangerous? • HAMR-Jr Time • Slow as a SlothBot • Healthcare Gone to the Dogs • Cheetahs Never Prosper • Bot or Not? • Do the Worm SERVO Magazine (ISSN 1546-0592/CDN Pub Agree#40702530) Issue-1 (Jan-Feb) is published • Draganfly Drones Do Monitoring 6X a year for $26.95 per year by T & L Publications, Inc., 2279 Eagle Glen Parkway, #112-481, Corona, CA 92883. Periodicals postage PAID at Corona, CA and at additional entry mailing • Follow the Bouncing Ball offices. POST MASTER: Send address changes to SERVO Magazine, 2279 Eagle Glen Parkway • Gonna Burst Your Bubble #112-481, Corona, CA 92883 or Station A, P.O. Box 54, Windsor ON N9A 6J5; cpcreturns@ servomagazine.com. 4 SERVO Issue-1.2020 07 Grant Imahara Eulogy by David Calkins Page 46 10 Experimenting with Walking Robots — Walking Up and Down Hills by John Blankenship This series of articles has explored many aspects of walking robots from the unexpected side effects of various movements to the need for sensors and how to utilize them. This final installment utilizes many of the principles discussed to create a robot that can navigate inclines as easily as level terrain. 16 Goal Prediction Using AI by Rajat Keshri 54 Versatile Stepper Control Learn the basics of machine learning and the power of by William Cooke what machine learning can do. This article teaches the Stepper motors are a staple of robotics. They’re great for implementation of different machine learning algorithms for precise speed and positioning. It’s also easy to control one. predicting a simple binary classification. It’s mainly focused But what about two, or three? With different step rates? on beginners who are very new to machine learning. As an For different amounts of time? While your microcontroller application to apply what you learn, you’ll discover how to continues doing other tasks? It can quickly become use different algorithms on predicting if a goal has been difficult, but with the technique presented here you can scored or not. do all that and use only about two or three percent of the microcontroller’s time. 38 Build Your Own Computer- Controlled Three-Axis Robotic Arm 61 Laser Alignment System for by Sam DiPietro, Brett Sawka, and Rohan Shah Your CNC Router Having a passion for art but no artistic skill, three by Roger D. Secura engineering students built a contour image plotter known In this article, I’ll show you how to build a laser power as “Bot Ross.” This article explains the design of Bot Ross’s supply circuit and a special bracket for your CNC router hardware and software as well as its intended operation. motor so that you’ll be able to consistently find the edges of your workpiece. You’re going to like the fact that the power 46 Building a Linear Actuator supply circuit we’ll make only requires three components: by Theron Wierenga the LM317T voltage regulator and two resistors. While doing some thinking about building a walking bird robot, I researched purchasing linear actuators. What I 66 Alpha-Writer: A Computer- found is that linear actuators are fairly expensive — especially Controlled Letter Writing Robotic if you’re an amateur robot builder with a limited budget. This led me to thinking about what it would take to build my Arm by V S Rajashekhar own linear actuators. In this DIY project, I’ll show you how to make a simple computer-controlled letter writing robot from scratch. It has two revolute joints connecting two links and at the end of the robot, there’s an end effector with a pen. By pressing a button on a screen, you can tell the robot which letter to do next. It can write all 26 letters of the alphabet. 70 Appetizer: Connected Cars — A Fast Brewing World in Automotive by Abhinav Kumar There’s a huge ecosystem of connected car services and mobility services startups, technology giants, consulting Page 54 companies, and finally, automotive OEMs that are working tirelessly to modernize the way we commute. SERVO Issue-1.2020 5 PUBLISHED BY Mind / Iron T & L Publications, Inc. CONTACT by Bryan Bergeron, Editor 2279 Eagle Glen Pkwy #112-481 Corona, CA 92883 OFFICE: (951) 371-8497 An Analog Artifact Worthy FAX: (951) 371-3052 www.servomagazine.com SUBSCRIPTION INQUIRIES/ of Your Robotics Toolkit WEBSTORE ORDERS TOLL FREE: (800) 783-4624 [email protected] store.nutsvolts.com PUBLISHER Larry Lemieux [email protected] ASSOCIATE PUBLISHER/ ADVERTISING SALES Robin Lemieux [email protected] EXECUTIVE DIRECTOR/ PRODUCTION Sean Lemieux [email protected] EDITOR Bryan Bergeron [email protected] CONTRIBUTING EDITORS Kevin Berry John Blankenship William Cook V S Rajashekhar Roger Secura Rohan Shah Sam DiPietro Brett Sawka Rajat Keshri Abhinav Kumar t my first real job with a I, on the other hand, lusted Theron Wierenga Ryan Clingman Nate Franklin David Calkins communications company, after one of the new digital meters Aevery technician was equipped on the market. After all, why settle WEBSTORE MARKETING/ with a piece of state-of-the-art test gear for a reading of only 2-3% full COVER GRAPHICS designed to function in the harshest scale accuracy, when a DMM could Brian Kirkpatrick environments and with literally theoretically take a reading with double [email protected] constant abuse. Of course, I’m talking the accuracy and to several digits and about the Simpson 260, easily the with a much higher input impedance? Copyright © 2020 by T & L Publications, Inc. most popular analog VOM (volt-ohm Putting aside the issues of settling All Rights Reserved meter) of all time. time, need for frequent calibration, All advertising is subject to publisher’s approval. We are not responsible for mistakes, misprints, The best technicians and and the need to be near a 110V or typographical errors. SERVO Magazine engineers wouldn’t consider anything outlet, when digital meters first hit the assumes no responsibility for the availability else to assist them in diagnosing market, they were cool. They were like or condition of advertised items or for the and maintaining microwave having one of the first iPhones to hit honesty of the advertiser. The publisher makes communications gear. I remember the street. no claims for the legality of any item advertised in SERVO. This is the sole responsibility of the the best of the engineers could read Over the years, I worked through advertiser. Advertisers and their agencies agree a dozen values in only a few seconds. several generations of DMMs, ranging to indemnify and protect the publisher from They could accurately estimate values from $10 to over $800. I even any and all claims, action, or expense arising long before the Simpson’s needle considered the digital Simpson — a from advertising placed in SERVO. Please send all moved into final position, simply based short-lived abomination. My current editorial correspondence, UPS, overnight mail, and artwork to: 2279 Eagle Glen Pkwy #112- on the initial velocity of the needle. toolkit includes a portable Fluke 87 481, Corona, CA 92883. 6 SERVO Issue-1.2020 Grant Masaru Imahara DMM and a benchtop Fluke 45 DMM. Other than changing batteries and October 23, 1970 – July 13, 2020 leads, these DMMs have been trouble- free and a cornerstone of my repair work. So, why did I add a Simpson 260 to my arsenal, especially when — on specifi cations alone — a DMM with similar capabilities can be had for 5% of the price of a used Simpson 260? I have to admit the reason is partly nostalgia. After all, handling the 3 lb over-sized Bakelite case and the solid “click-click” rotary switch is pure pleasure. Instead of a series of cold LED or LCD numbers, my measurements are based on a crisp black needle defl ected across a colorful mirrored background. My reason for acquiring the Simpson 260 (Simpson 260 8p, used, with leather case, $175, eBay) is also partly practical. Measuring the voltage across and current through motors and other actuators is simply easier with an analog meter. The analog meter movement is relatively immune to higher frequency noise and spurious by David Calkins signals, making measurements a lot easier. henever we talk about the famous, we call them “stars.” In fact, I’ve found the Simpson The dots of light in an otherwise black sky.