Skip to content


Switch branches/tags

Latest commit


Git stats


Failed to load latest commit information.
Latest commit message
Commit time


This project is kind of the modern day cup-on-a-string communication device. Originally conceived to connect two different desks in an office with a fun, hard-wired communication pipe, Raspberries-on-a-String is a fun way to send messages via a 16x16 LED matrix on one end and 5 buttons on the other. This project utilizes a Raspberry Pi and the Unicorn Hat HD and Button Shim from Pimeroni. Check out the media below and the setup guide if you want to run it yourself.

In Operation


There are a few network and system settings that you'll need to configure before you can connect your two Raspberry Pis together and have them talking. Below is most of what you'll need. I made this list from my memory so if you come across an issue please let me know and I may be able to help you out.

  1. Assemble the Pimeroni Unicorn Hat HD and Button Shim.
  2. Get an SD card with the latest verion of Raspbian
  3. Configure static IP addressing in /etc/dhcpcd.conf and connect the Pi to your router via an Ethernet cable.
  4. Recommended: I really like interacting with Pis in headless mode. I use most of the steps from the exellent guide here. Keep in mind that if you use that guide you'll need to whitelist the ports used by office-communicator.
  5. On the Pi, configure Unicorn Hat HD and Button Shim via the utilities on their GitHub pages (Hat, Shim)
  6. Optional: Try out some of the example programs to make sure you've assembled everything correctly.
  7. Clone the office-communicator repository.
  8. Configure a systemd service to run and on boot.
  9. Reboot your Pi and make sure the default display starts up. You can also test out the software if you run with the argument --loopback.
  10. Set this up on a second Pi once you have it running on one. You might want to just make an image of this first one and apply it to a fresh SD card. The guide for setting your Pi up in headless mode had commands for how to create and write images.
  11. On the second Pi, you'll still need to configure a DIFFERENT static IP address and make sure that in on each device that you have the address of the other device.
  12. You should be able to get them talking to each other even with both connected to the router. You can then connect them directly together and that should work too.



Raspberry Pi based cup-on-a-string. Send messages via buttons to the other 16x16 LED matrix.







No releases published


No packages published