To sense the location of the players hands I use ultrasonic transmitters and receivers. The following diagram shows the arrangement.

        L       R

    X   A   Y   B   Z

There are two ultrasonic transmitters, A and B, three ultrasonic receivers, X, Y and Z, and two players hands, L and R. First transmitter A transmits a series of pulses which reflect off hand L and is received by receivers X and Y. The controller measures the time of flight for ALX and ALY. Next transmitter B transmits a series of pulses which reflect off hand R and is received by receivers Y and Z. The controller measures the time of flight for BRY and BRZ. From these times I calculate the four desired values, left pitch, right pitch, left volume, and right volume.

The controller for this project is a Raspberry PI Pico-W. I chose the W version so I can use a Bluetooth interface to a notepad with control software. To create the sound output I wanted to use a couple of SID chips from the Commodore 64 that I used in college. Am I dating myself? However, today these chips a expensive and hard to find. After some research I settled on a pair of the TI SN76489 sound generators.