Download the zip file below and use the STL file inside for 3D printing. The source file, in "scad" format, is also included if you want to modify the design using OpenSCAD.

The print size is about 175 x 35 x 40mm.

The file is designed to print without supports using a layer height of 0.2mm or less.

Solder male pins headers to the display and to your Feather, with the pins "down" as usual for breadboard use. Use 75mm jumper wires to wire the matrix and display to a CircuitPython Feather (such as the nRF52840 Feather)  Keep the wires in bundles, especially the row and column bundles. Make the following connections:

  • Matrix "column" pins to D10, D9, D6, TX
  • Matrix "row" pins to A0, A1, A2, A3, A4, A5
  • Display pins to feather pins: CLK to SCK, DI to MO, CS to RX, GND to GND, VIN to 3V

Assembly uses nylon M2.5 screws, nuts, and standoffs. Place the feather in back, pins up in the air. The best order for assembly I found is:

  1. Loosely secure 4 short stand-offs in the keypad area. I used F-F standoffs and screws.
  2. Place the keypad on top, adjust the stand-offs within the slots, and add screws from the top
  3. Tighten the bottom screws until the keypad doesn't shift around anymore
  4. Follow a similar procedure to secure the Feather
  5. Insert nuts in the 4 slots, then 4 long M-F stand-offs into them.
  6. Place the screen on top and secure with screws. Note the correct orientation of the screen.
It turns out not all nylon M2.5 nuts are created equal, so if yours don't fit in the little slots under the display, you'll have to get creative -- sand them down, hot glue the stand-off in place, modify the 3D print file, etc.

This guide was first published on Oct 21, 2020. It was last updated on Oct 21, 2020.

This page (3D Printing, Wiring & Assembly) was last updated on Oct 02, 2021.

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