The Theramin ( is a musical instrument that makes spooky synthesized sounds as you wave your hands in front of it. It was used in the theme music for the original Star Trek series.

We are going to make a similar instrument, albeit a lot less musical, but it will change the pitch of the note as you wave your hand in front of it.

We can leave the piezo sounder where it is, attached directly to the Arduino, but we will need the breadboard for the photocell and resistor that are going to control the pitch.

This guide was first published on Dec 12, 2012. It was last updated on Dec 12, 2012. This page (Pseudo-Theremin) was last updated on Jun 24, 2019.