Synchronized Video Player for the Raspberry PI using MQTT

This is a small node app that uses MQTT to synchronize the playing of videos on multiple raspberry pis. A single controller instance listens for connection messages (/ready) and counts how many nodes have connected. When every node is ready, the controller tells all nodes to play one minute in the future (to help account for differences in the message being recieved). When the video is finished playing, nodes send a /done message and the controller waits until all nodes are done, and then sends the /play message to start repeat loop.

App Config

The config file contains 5 variables. totalNodes is the number of nodes who are synched video is the path to the video file to play actAsController should be true for the machine that is acting as the controller for the network. All synched nodes should only have 1 controller. controllerUrl is the IP or hostname of the machine where the controller lives. This is only necessary on machines that aren't the controller. See below to set the hostname so you can use the X.local syntax and not fret of IP addresses. volume is the initial volume for the video

Pi Setup

Turn off the mouse and disable screen sleeping

sudo nano /etc/lightdm/lightdm.conf then at the end of the "[Seat:*]" section, add: xserver-command = X -nocursor -s 0 dpms

If using the hyperpixel, also follow the steps here: https://github.com/pimoroni/hyperpixel#disabling-power-save

Also there is a flash to the desktop when the video completes, if you set the desktop background to black, remove the trash, and hide the taskbar you won't see it.

Change Hostname

This isn't totally necessary, but it will make life easier when setting the controllerUrl https://www.tomshardware.com/how-to/raspberry-pi-change-hostname

Install nodejs

See this gist for pi zero https://gist.github.com/Koenkk/11fe6d4845f5275a2a8791d04ea223cb

Install Dependencies

npm i

Install PM2

sudo npm install -g pm2 After install you need to get the daemon running, easiest way is to run pm2 status which you can use in the future to see the status of your app.

Run the app with PM2

cd into the directory with the code, and run pm2 start app.js --name mqtt-player then "save" the app by running pm2 save

If you need to make changes in the future, you can control the process with pm2 stop mqtt-player and pm2 start mqtt-player

Setup PM2 to run on startup

pm2 startup and follow the onscreen instructions. If you ever want to undo this you can run pm2 unstartup systemd

Sometimes it is helpful to see the application output, you can do that but running pm2 log