Arduino Ultrasonic MIDI
This uses a HC-SR04 Ultrasonic Sensor to send Control Change messages to music software. The Arduino requires a virtual MIDI device to communicate with music software.
Some links to software and potential usage here
https://tinyurl.com/y7fslb83
This code is suitable for any Arduino but If you have a Leonardo, Micro or Due try
https://github.com/psiconlab/Arduino_Ultrasonic_MIDI_Native