This light theremin project is an excerpt from Make:’s Basic Arduino Projects by Don Wilcher.

Arduino Photocell Theremin
Photo: Pierre-Alexandre Luyt

Electronic circuits that produce audible sounds have been used to create strange and eerie audio effects for science-fiction movies like Star Wars and Marvel’s The Avengers. The Theremin is a device that generates different electronic sounds by waving hands over and around a pair of protruding antennas. You can make your own awesome Theremin using a few electronic components from the Ultimate Microcontroller Pack. The Theremin in this project will not use a pair of antennas but a photocell to interact with the device. Also, a simple transistor amplifier will be built to enhance the volume of the electronic sounds created with your Theremin.

The Parts List shows all of the electronic components available from the Ultimate Arduino Microcontroller Pack to build your own Theremin.

Project Steps

Build the hardware

Wire the components as it is shown on the diagram. Here we chose to wire the photocell to analog 0 and the transistor to the digital pin 9 on the Arduino.

Pay close attention to the 100 uF electrolytic capacitor’s orientation

to prevent damage to the Arduino. The mini 8Ω speaker color wire leads must be

connected correctly in order for the audio electronic

sounds to be heard through it.

Upload the arduino sketch

Upload the sketch on your Arduino software.

You can adjust the value of the range your photocell is giving opening the serial monitor (at the top right of your Arduino window). Observe what is the highest and the lowest value coming from the photocell, and write them in the sketch.

Play music

Waving your hand over the photocell will change the sound emitted by the speaker. Now you can play a very weird electronic music!