A DIY Custom Designed, Monochrome, E-Ink display badge powered by the RP2350A, inspired by the GitHub Universe 2024 conference badge. ~Kinda wanted to see how many words I could describe it with..
(Renders made in Fusion 360)
- MCU: The mighty RP2350A I wish the RP2354A were in stock though
- Flash: 16MB onboard but do I want it to remember?
- Power: Integrated battery management for a single-cell LiPo, does it charge idk
- Display: E-Ink support over SPI, this was painful for part selection
- Software: No dedicated firmware/software yet — I'm considering adapting the Badger 2040 software from the GitHub Universe conference badge as a starting point, don't have the time for it
This board has some fine-pitch and hand-soldering-unfriendly parts (the RP2350A and the E-Ink display's FPC connector), so I'd recommend using a PCBA service for the main board rather than hand-soldering it yourself. I know I wouldn't I have tried and failed, mainly cuz I dont have a hotplate.
Most components will already be populated(i liked this fancy word better than placed) by the assembly service — you'll only need to install the battery and the display yourself:
Bring your own adhesive, please ~ Not on BOM cuz not required for functionalityy
- Prepare the battery connector: Trim the battery connector's legs slightly so they don't press against the back of the display once everything is assembled.
- Mount the battery: Apply adhesive to the marked area on the PCB and stick the battery down.
- Connect the battery: Plug the battery cable into the battery connector on the PCB.
- Mount the display: Apply adhesive to the marked area on the front of the PCB and attach the E-Ink display.
- Connect the display cable: Route the ribbon cable through the indentation/slot in the PCB. Open the FPC connector's clamp arm, insert the ribbon cable, then press the clamp lever back down to lock it in place.
"That's it — the badge is fully assembled", I'd like to say, whether the firmware actually works, is what I'd like to know.
For getting started with software, I'd recommend flashing CircuitPython, as it's the easiest way to get up and running. Also have some demo firmware included in this repo, though it's untested/may not work out of the box.
I have some basic firmware in this repo. If you'd like to write your own, here are the SPI pin mappings for the display connection:
| Signal | GPIO |
|---|---|
| SCLK (Clock) | GPIO 2 |
| SDI (MOSI/Data) | GPIO 3 |
| D/C (Data/Command) | GPIO 4 |
| CS (Chip Select) | GPIO 5 |
| RES (Reset) | GPIO 6 |
| BUSY | GPIO 7 |
- Project BOM — full parts list for the badge
- PCB BOM — parts list specific to the PCB assembly
- In part research
- Part finding (lcsc is hit or miss at finding stuff)
- Firmware Demo creation
- README Build Guide (code completion - fancy autocorrect ig)
