Pseudonymous developer "boochow" has used the popular Raspberry Pi Pico in the heart of a MIDI device with a difference: Rather than making music, it's designed to monitor and display the MIDI signals received from a USB MIDI device.
"[The Raspberry Pi Pico] SDK's TinyUSB Library makes USB devices relatively easy to create," boochow explains in translation, "or connect USB devices. This time, I tried to create a MIDI device that outputs MIDI messages received via USB to UART. TinyUSB also includes a variety of sample codes and MIDI devices. The sample code was a sequencer-like device that outputs MIDI messages to USB, so I made it different."
The project requires minimal wiring: The Raspberry Pi Pico, launched earlier this year as a $4 combined breadboard-friendly development board and surface-mountable productizable module, connects to a host PC via USB and acts as a MIDI device; the two pins closest to the micro-USB port on the left-hand side are used as UART transmit and receive to output the captured and decoded MIDI signals.
"This time I'm just outputting to UART," boochow writes, "but in combination with [other projects] you will be able to make a synthesizer that works with USB-MIDI with Pico."