You can salvage some nice motors out of optical drives but they can be tricky to control. That’s because brushless DC motors require carefully timed signals used in a process called Electronic Speed Control (ESC). [Fileark] built and ESC using an Arduino and has a couple of posts explaining the concept and demonstrating how it works. His test circuit uses six 2N2222 transistors to protect the Arduino from excessive current. You can see six red LEDs above which are inline with the base of teach transistor. This gives visual feedback when a transistor is switched, a big help for troubleshooting your circuit.

Once you’ve seen the videos after the break you’ll probably come to the conclusion that this is an impractical way to use a brushless motor. But it is a wonderful way to learn about, and experiment with the concept of ESC. Chances are you can get your hands on an old optical drive for free, making this an inexpensive weekend project.

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Hub motors put the power inside of the wheel. [Teamtestbot] goes deep into the hows and whys of building these motors, from parts, to windings, to the math behind the power ratios. The working example puts an electric motor inside the rear wheel of a Razor scooter. Past projects used belts to transfer the work of the motor to the wheel of the scooter. By integrating the motor and the wheel you end up with a much cleaner looking product. Check out the motor testing and the scooter test drive after the break.

For more tips on building your own electric motors take a peek at the Fly Electric page we covered back in November.

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[Jerome's] been working on some improvements to an electric foot scooter he picked up from a friend. He ordered up a powerful brushless motor and some lithium batteries. His system uses a belt drive and at 33 volts it can reach 25 miles per hour.

He had some problems with too much torque when the motor was first started. This resulted in unintentional wheelies, which sounds really cool if you’re not the one trying to hang on to the scooter. [Jerome] is using an Arduino to control the system so he built in the ability to gradually ramp up the speed of the motor and also added the ability to control the speed via remote control. You should note in the video after the break that [Jerome] is test-piloting his build sans-helmet.

So, we spend a lifetime and countless sums of money filling our noggins with knowledge. This is a precarious investment since a rather small bump to the melon could corrupt all of that data and end the once spectacular cognitive power. If you’re smart enough to build a foot scooter that can go 25mph, be smart enough to wear a helmet when you ride on it!

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