Weekend Projects - "Drawdio" Musical Pencil

Complete instructions for this episode of Weekend Projects can be found at
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Drawdio is a simple electronic sound synthesizer build onto a pencil! The Drawdio circuit plays a musical tone with a frequency that varies based on the resistance between two points. When you hold the Drawdio in your hand, your body becomes part of the resistive loop, and you can do all kinds of fun tricks, like draw yourself a piano and play a little tune.