An Arduino Uno controls the servos, as well as the stepper motor by way of a TB6600 controller, and optical limit switches are used to make sure nothing moves out bounds.

Making a servo tester using an Attiny85 micro chip, Attiny45 also works for this project. This diy servo tester is as good as ...

Also note that the Theremin demonstrated here is a stripped-down (and tricky) version of the far-famed proximity-controlled musical instrument – the key difference is that it employs a cheap light ...