This Open Source Theremin Uses a Pair of Optical Proximity Sensors
Make sounds with a wave of your hand! Sounds crazy? This is possible through the invention of the theremin, an instrument that can be played without being touched.
While most of theremins employ an electromagnetic field, the optical theremin uses light sensors or an infrared field — as seen in Fearless Night's project, which integrates a pair of optical proximity sensors in place of radio frequency fields.
Similar to classic theremin, this optical variant also controls the volume and frequency through the sensors. Control knobs are available in the design to select the pitch, waveshape arrangement, LFO (vibrato), and distortion effect. Fearless Night's device is based on the STM32F103C Blue Pill board-, which features an Arm Cortex-M3 core running at a clock frequency of 72MHz.
The software is compatible with Arduino, and demo files are available for download. Being an open source project, you can easily tinker around with the hardware schematics and the software behind the design.
The hardware is powered via a USB micro jack with 5.0V and 500mA specifications.
The technology behind the product is the STM32 DMA DDS signal generation and a simple low pass filter, producing 16-bit single channel (mono) sound. With the simple setup comes less hassle to play with the hardware requiring a 5V USB power source and 3.5mm stereo audio cables.
For more information on the controls and its open source hardware and software, be sure to check out Fearless Night's project page.