Electric Keyboard on the Super-Cheap

Posted On: May 11, 2013

Each year, MIT has a(n absolutely incredible) weekend of events for prospective freshman (herein referred to as prefrosh). Next Make always has an event to teach prefrosh basic soldering skills, how easy making your own electronic trinkets can be, and of course how awesome Next House and Next Make are!

This year, based on some inspiration from different sources, I came up with a way to make an electric piano at just a few dollars a pop. The results aren’t pretty for that price, but work well enough!

Essentially, you just draw on paper with graphite, the conductive material used in pencils. The graphite will have some resistance between two connected points, which varies with line thickness, layer height and distance. This resistance can be used with a 555 timer, which charges and discharges a capacitor to make an oscillating signal. The frequency is related to the time it takes to charge the capacitor, which depends on the resistance. The frequency of the sound depends, then, on the resistance through the piano.

About 40 prefrosh stopped by to make a circuit, the halls rang with 8-bit-esque sounds! For a moving sample of how to play the piano, our very own Eva plays piano.

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