Created 9 months ago
Maintained by mhuin
a test project
Members 2
Fabien Boucher committed 9 months ago


OpenSource library to talk to a Populele's Led matrix

If you're interested about the story behind the project, how this came up to be, as well as more technical detains, I have another doc for you.

BlueZ to talk to the Populele right away

If you want to talk over bluetooth to your Populele, use


  • No need for new hardware


  • Not possible to set PWM per LED
  • Kind of slow
  • BLE is kind of unreliable

The script requires some dependencies. It is recommended to install them system wide (see pygobject if you want to use PuPI)

apt install python-pydbus python-gi

Make sure BlueZ is up and running. I've tested that everything works with version 5.50.

Then just hack the script to your liking and run python

Connect your own board to the Led Matrix


  • Full LED matrix control over i2c
  • Fast & reliable


  • Need to remove all the smart from the ukulele and insert your own.

The code should currently work on any board that can run Adafruit's CircuitPython.

I use the Feather M0 Bluefruit, as I intend to also implement my own BLE protocol. This one also has a battery charging circuit.

Wires & stuff

This is a bit trickier. Once you disconnected everything from your Uke, you'll be left with a JST-style connector. When looking at it you get the following pins:

          ___      ___
    _____|   |____|   |______
   |                         |
   |    5V     GND     SCL   |
   |                         |
   |    SDB    INT     SDA   |

Connect SCL/SDA/5V/GND to the same pins on your microcontroller board (5V is the one directly connected to USB).

Then put INT to GND, and SDB to pin D10.

Also remember SCL & SDA need to be Pull'ed UP, so connect them to 5V via a 4.7K resistor for each line.

Stuff everything back into the ukulele and you should be good to go.

Push the code

Your CircuitPython enabled board should expose a mass storage device. Just copy the relevant files to it:

mount /dev/sdXY /mnt/SOMEWHERE
cp /mnt/SOMEWHERE/
cp -r animations /mnt/SOMEWHERE/
umount /mnt/SOMEWHERE

Add your own animations

This project is heavily influenced by the Best Badge Ever.

Both the CircuitPython and BlueZ scripts call whatever animation object Draw() method every interval milliseconds which in turn will call the Populele objects SetXXXX methods to change internal state.

See animations/ for an example.