MiniDexed Hat for Raspberry Pi

This aims to make the construction of a MiniDexed a little easier.

Features:

• On-board step-down converter to run from a typical 12V wall-wart power supply to sidestep the exacting USB-C requirements of the Raspberry Pi 4
• Direct mounting for a PCM5102A audio module, with output routed to headers
• Headers for connecting peripherals:
  • 8 pins for a 1602 display (using this backpack board)
  • I2C for an OLED display
  • Left and right line out
  • Serial MIDI for a 3.3V MIDI interface
  • KY-040 encoder module

Revision 1 does not include debouncing capacitors for the encoder. I intend to make my own encoder boards with better debouncing.

The PCB dimensions are based on Seth Hillbrand's template for a Raspberry Pi hat.

With an appropriate display, this board should also work with mt32-pi, but I have not tested it.

Warning

Set the voltage on the converter before soldering the audio interface in place or installing the hat on the Pi. I recommend around 5.2V.