This was trivially easy, but it’s a nice example of how simple integration is now becoming due to the strength of various open source communities.

Pi-LITE

The Pi Lite is an array of lots of LEDs (126 in a 9×14 matrix to be exact). I bought a pair of them during the initial Kickstarter campaign. It has its own micro controller, and is accessed via a serial port[1], which means it’s pretty easy to get messages onto it from most languages and frameworks.

Node-RED

Node-RED is a visual integration tool that runs on node.js. It’s very easy to get it going on a Pi using Raspbian:

# First install node.js
wget http://node-arm.herokuapp.com/node_latest_armhf.deb
sudo dpkg -i node_latest_armhf.deb

# Make sure we have git
sudo apt-get install -y git-core

# Install Node-RED
git clone https://github.com/node-red/node-red.git
cd node-red
npm install --production

# Install serialport package
npm install serialport

#Start Node-RED
node red.js

Once up and running browse to http://pi_ip:1880 and wire together a ‘Hello World’ example with an inject input (with a Paylod of ‘Hello World’) and a serial output (configured for /dev/ttyAMA0 at 9600 baud):

Now clicking on the button on the Hello World injector results in Hello World scrolling across the Pi Lite in large friendly letters :)

Once that’s running then it’s easy to substitute messages coming from tweets, MQTT queues or whatever else and feed them onto the matrix.

Note

[1] Since the GPIO serial port is normally set up for logging and console access it’s necessary to do some reconfiguration before using the Pi Lite.