Let’s control volume with a (moderately) fancy knob! AS5601 might be my favourite sensor right now. It’s an on-axis magnetic rotary position sensor. It generates a signal typical for encoders, but it does it by detecting the change in a magnetic field of a diametrically magnetized, rotating magnet. The knob acts as a USB HID device. That means that, currently, it can do everything that a 2 button keyboard could do.
