I built the board end to end: 16 physical controls (faders, knobs, and buttons) multiplexed into a Raspberry Pi Pico, which sends changes over a custom serial protocol to a Node server on a Raspberry Pi with a touchscreen. It supports Bluetooth and wired audio, has a custom 3D-printed enclosure, and receives updates over Tailscale.
When the controls started spiking, I captured live serial data and ruled out faulty potentiometers. I traced the noise to hand-soldered joints and a shared ground, then designed a v2 PCB in KiCad with filtered analog inputs and a ground plane to reduce it.