He’s converted a mouse into a tuning dial. The scroll wheel on a mouse is nothing more than a rotary encoder, and can easily be used as a sort of tuning knob. Replacing it with a better encoder ...

At the heart of the device is a AD9833 waveform generator; with the Arduino, rotary encoder, and 16×2 LCD providing an interface to control it over SPI. Unfortunately, the AD9833 doesn’t have ...