A portable, rechargeable theremin using ultrasonic transducers for distance sensing. Connect the device to any consumer-grade speaker or directly to your computer to record your sound!
Take a look at the schematic
Feedback and derivatives are welcome! NOTE that the firmware files are licensed under a permissive MIT OSL, but the hardware is licensed under a strongly reciprocal CERN-OHL-S license which means all derivatives must undertake the same license.
Thanks, Neil