When a plant is up and running, the noises emanating from the machines can sound like an industrial symphony. But what if you could use those assets to play your favorite classical overture or chart topper? Josh Sheldon has done just that with this stepper motor organ.
According to Josh: "I've spent the last two months building this very strange instrument. The idea came a few months ago, when I was thinking about how stepper motors work and the idea occurred to me that steppers would probably generate alternating current when backdriven. I got an oscilloscope and I found that this was true, which was exciting because that meant that I could use stepper motors to generate sound. This is because AC is a wave, which is what sound is. If you amplify the signal and send it to a speaker, you can listen to it as sound. The frequency of the signal from the motor is proportional to how fast the motor is driven. So if you backdrive the motor at a high speed, you get a high pitch, and a low speed would give you a low pitch. The wave I got from my stepper motors was more or less sinusoidal, which meant I'd get sound similar to what you get from a sine synthesizer."
