Hobby servos are small, modular actuators developed by the radio control (RC) hobby industry for remote manipulation of everything from miniature boat rudders and car steering linkages to model airplane flaps and toy parachutist release mechanisms. The RC market is large and competitive, which has led to a proliferation of servos that have been optimized for characteristics including size, speed, torque, and price. This modularity, variety, ubiquity and cost-effectiveness of servos make them attractive generic actuators for small robots and other electromechanical systems. Continued…

Two ShiftBrites controlled by Mini Maestros power a flashlight capable of displaying one million colors with many interesting modes of operation. For more details, see Reed Kimble’s forum post: My Absurd Project – The One-Million-Color Flashlight!.

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	Mini Maestro 12-Channel USB Servo Controller (Partial Kit)
	ShiftBrite

This hand-held Tic-Tac-Toe game is powered by a Pololu adjustable boost regulator and controlled with a Pololu Baby Orangutan B-328.

Featured link: http://forum.pololu.com/viewtopic.php?f=2&t=2782

My last post about force and torque got kind of long, prompting some suggestions that I break it up into two separate posts. I didn’t do it because my sentiments about units and the common confusion of weight and mass applied to both topics. I want to move on to a thorough discussion of hobby servos, which is broad enough of a topic that it definitely merits a breakdown into multiple posts. That got me thinking about the order in which to present the material. So, this post is mostly about organizing and presenting information and not really about servos. Continued…

I got a few private requests for more information about torque after my post on units, and since torque is relevant to the next few posts I want to make about servos, I’ll try to explain torque a bit more today. Torque is intimately connected to force, so we’ll start with a review of Newton’s laws of motion. You should know some basic calculus to really understand these concepts, but getting into that is beyond the scope of this post; I hope I hit the right level of simplification to provide some useful knowledge to those who have some basic intuitive mechanical sense but have not taken, or have forgotten, basic physics courses. Continued…

This video shows a “Useless Machine” controlled by a Baby Orangutan. It counts how many times the button is pressed, and then the arm comes out and presses the button the same number of times. The author has also posted source code for the project.

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Baby Orangutan B-328 Robot Controller

With Christmas just a few days away, and having just discussed a single LED circuit and simple parallel circuits, I’d like to make a few comments about using multiple LEDs. I’m still talking about basic LEDs, and not too many of them; for specialized LEDs or large arrays, there are all kinds of chips designed just for that. Continued…

Customer Ana Paula Almeida wrote this Portuguese-language paper about the 3pi Robot (1MB doc) as part of a Master’s program in Computational Modeling and Industrial Technology. The paper describes the 3pi in general and specifically how to write optimized maze-solving code.

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Pololu 3pi Robot

If you have a limited or informal electronics education, parallel circuits might be the kind of topic you glossed over or have forgotten about. After all, parallel circuits sounds like boring theory, and you want to get to the fun stuff. But, banging your head over a simple system that you think should just work isn’t much fun, and you can save yourself a lot of grief with a bit of awareness about the potential differences between a schematic and a physical circuit. Also, I’m a proponent of learning fundamentals and trying to really understand things, so we’ll start with a bit of the basic theory. Continued…

The simple LED circuit from last time is a great first circuit for everyone interested in electronics because it is so forgiving. If you connect something backwards, you probably won’t break anything, and otherwise, it should just work. However, that forgiving nature of the circuit can beguile newcomers into thinking everything is that simple, and though there are many web pages out there discussing the circuit, they usually do not address the abstractions and simplifications that are in play and why we can use them in this instance. So, that’s the topic for this post. Continued…