PommaBuy one ready-made

Build your own

Print it, wire it, build it yourself.

If you have a 3D printer and a soldering iron, you can make your own Pomma. The case files, parts list and wiring are free for personal builds.

Download the plansZIP, 2.3 MB · STL, STEP and the CAD script

Prototype design. Checked in CAD for fit, not yet test-printed. Print the two test coupons first.

CAD render of the case with the lid lifted, showing the Pi, speaker board, button and dial

What you need

  • Raspberry Pi 3A+plus a microSD card
  • Freenove GPIO terminal boardFNK0080, and a riser of about 8 mm for its centre header
  • Pimoroni Pirate Audio: SpeakerPIM485: the screen, speaker and amplifier in one
  • Adafruit rotary encoderADA377, with a 25 mm knob (6 mm bore)
  • 24 mm mini LED arcade buttontranslucent red, The Pi Hut 104403
  • Mini USB microphoneplugs straight into the Pi
  • 5 V 2.5 A micro-USB power supply
  • Screws and wirefour M2.5 × 12 with standoffs, four M3 × 10, 24 AWG silicone wire, a cable tie
  • A pay-as-you-go SIMto give the box its own WhatsApp number

Plus PETG or PLA filament and basic soldering.

How it goes together

  1. Print the test pieces. One checks the button hole, the other the dial and screw holes.
  2. Print the case. The base prints upright, the lid face-down, no supports.
  3. Wire the controls. The dial and TALK button screw into the terminal board before the speaker board goes on.
  4. Set the height. Measure the stack and add printed shims so the screen sits just under the lid.
  5. Close it up. Four screws from underneath.

Full print settings, wiring pins and the height formula are in the README inside the download.

Software

The box software will be released under the GNU GPL version 3, which lets anyone use, change and share it. Until it’s published, these plans cover the case, parts and wiring.

Kits

Parts kits are coming. If you’d rather skip the printing and soldering, buy one ready-made.

Licence

Free DIY plans for personal, non-commercial builds. Case designs, CAD script and guides: © 2026 Ed Dowding, CC BY-NC-SA 4.0. Credit Ed Dowding, say what you changed, and share changes under the same licence. Please don’t sell boxes or kits made from these plans; ask us about commercial use. The software is licensed separately under GPLv3. The Pomma name isn’t covered by the licence.