Servo - July 2012

Then

and

NOW

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Sensors For Mobile Robots — Part 3

by Tom Carroll

The last two months, I’ve been referencing Bart Everett’s sensor book from 1995 — Sensors for Mobile Robots — a book that, in my opinion, should be on every robot experimenter’s bookshelf. Everett’s book emphasizes just how critical the need and use of sensors is for successful robot designs. His book not only describes how they work but which ones to use and how to use them. Though it was published 17 years ago, almost all of the types and technology involved are still appropriate for today’s robot designs.

In this series on sensors for mobile robots, I have referenced Everett’s book so much because it has always been an inspiration for me. The Navy and Everett’s robots

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have certainly advanced quite a bit since he first started building his series of ‘Robart’ robots as test platforms. Not only has onboard computer intelligence advanced, but the associated sensors have made amazing leaps in technology. Robots rely quite a bit on advanced mechanical and power systems, but it is sensor technology coupled with computer science that has created the amazing robots that we see in the forefront of today’s military actions and surveillance.

As robot experimenters, most of us want to keep abreast of the latest advances in any science and engineering aspect of our creations. We certainly don’t have the seemingly unlimited funding like the military, so we must rely on the best that we can find for the lowest cost. I have tried to present the best solutions in sensor technology that I could find from robot manufacturers and suppliers while keeping most products below $100. A lot of the products that I have reviewed have been in the $10-$50 range, except for the MaxBotix weather-proof sonar at $100 and the Parallax laser range finder at $130. This month, I will discuss some unique sensors — most of which happen to be from Parallax, and range in price from $6 to about $60. I do encourage you to look at the great products from all the robot-specific companies.