Overview

What is a theremin?

A theremin is an electronic musical instrument that you can play without even touching it - spooky! The theremin senses the distance from its antennae to the player's hands, and changes its pitch and volume based on these distances. The theremin was used to make soundtrack music for many iconic spooky movies, like The Day the Earth Stood Still (1958), and is perfect inspiration for a Halloween project!

Here, I've turned a pumpkin into a Jack-o-Theremin using an ultrasonic distance sensor and a Circuit Playground Express (CPX). The CPX uses the distance measurement to generate a sound and flash the onboard NeoPixels in various colors. This version of a theremin has a much more digital-bleepy-bloopy sound than a traditional theremin, but you still get to make music by waving your hand around in the air!

Materials

You'll need:

Circuit Playground Express

PRODUCT ID: 3333
Circuit Playground Express is the next step towards a perfect introduction to electronics and programming. We've taken the original Circuit Playground Classic and...
$24.95
IN STOCK

HC-SR04 Ultrasonic Sonar Distance Sensor + 2 x 10K resistors

PRODUCT ID: 3942
If you're like me, you've dreamed of being a dolphin - smoothly gliding through the water. Using your echo-location abilities to detect tasty fish treats. Until genetic...
$3.95
OUT OF STOCK

3 x AAA Battery Holder with On/Off Switch and 2-Pin JST

PRODUCT ID: 727
This battery holder connects 3 AAA batteries together in series for powering all kinds of projects. We spec'd these out because the box is slim, and 3 AAA's add up to about...
$1.95
IN STOCK

Mini Metal Speaker w/ Wires - 8 ohm 0.5W

PRODUCT ID: 1890
Listen up! This tiny 1" diameter speaker cone is the perfect addition to any small audio project where you need an 8 Ω impedance and will be using 0.5W or less of power. We...
$1.95
IN STOCK

2-pin JST SM Plug + Receptacle Cable Set

PRODUCT ID: 2880
These 2-wire cables are 16cm long and come as a set.  One side has a 2-pin JST SM type connector plug on the end.  The other side has a matching 2-pin JST SM type...
$0.75
IN STOCK

Note: For my project, I used a scavenged speaker that I had in my spare parts box, but the speaker listed above will work just fine!

You'll also need a pumpkin to carve, and I highly recommend choosing a plastic or foam pumpkin for this project. That way, you can enjoy your Jack-o-Theremin for many Halloweens to come! If you do build this into a real pumpkin, you'll need to cover all the electronics with plastic wrap or seal them in a plastic bag inside the pumpkin.

This guide was first published on Oct 28, 2018. It was last updated on Nov 17, 2018. This page (Overview) was last updated on Oct 26, 2018.