Build Your Own Theremin With Arduino

Interference is generally considered harmful, and particularly vulnerable to it are high impedance circuits. Electromagnetic interference (EMI) is generated by many household appliances that use switching power supplies and the number of these appliances in our homes is increased each and every day. The changing magnetic fields around us also generate a small voltage potential in our bodies — that can be easily checked if you touch the tip of an audio jack from any kind of amplifier.

Basically, the higher the impedance of a circuit, the higher the sensitivity of said circuit. An input of an amplifier has an input impedance of anywhere from about 600Ω for line input gear, up to 50-100kΩ for high impedance amplifiers for guitars. It’s amplifiers that sparked my interest. What could happen if I increased the input impedance to a hilariously large value, and try to utilize it for something? Trying this with an Arduino immediately came to mind, with it’s ADC input impedance of over 10MΩ, and I wanted to see what exactly could be done with it.

[paranormalwien]

Good project. But what are you holding with your left hand ? And why do I need an Uno and an ATMEGA328P-XMINI ?