(rPi + Homebridge) Media Center Home Automation

The Gist

Use an iOS device and the HomeKit API to control a Raspberry Pi acting as a home media center server-router. The rPi runs Homebridge which is a Node server that spoofs itself as a HomeKit device. Then, define a custom configuration which suits my needs (5x1 HDMI switcher and projector on/off power states). I found an HDMI switch that has RS-232 Serial input and a projector that has an IR remote control which we can emulate with an IR led connected to the rPi’s headphone jack.

Ingredients

Hardware

• Raspberry Pi 2 Model B
• Projector with IR remote control input - what I bought
• 5x1 HDMI Switcher with RS-232 control input - what I bought

Software

• Homebridge
  • spoofs the HomeKit device
  • runs on rPi
• homebridge-switcheroo
  • Homebridge plugin that make simple switches which trigger http requests
  • traditional on/off switches or radio button multi-switches
• forever
  • script that makes sure your servers relaunch if a crash occurs

Raspberry Pi Setup

(Optional) Set a Static IP

If you are using your rPi as a server, you may want to give it a static IP. You probably know if you want this, if not, people have written about it.

Example setup that could be added to your /etc/dhcpcd.conf:

... 
interface wlan0

static ip_address=192.168.0.XXX
static routers=192.168.0.1
static domain_name_servers=192.168.0.1

(source)

Install Homebridge

Follow nfarina's guide on how to install Homebridge on a Raspberry Pi.

Auto-restart Homebridge after a crash

Install forever.

Tell forever to run Homebridge, forever... forever start /usr/bin/homebridge

Handy commands to have around:

• Stop Homebridge from restarting: forever stop /usr/bin/homebridge
• List forever servers running: forever list

Run Homebridge (or any Node server) on Startup

crontab -u pi -e

Replace pi with whatever username you may use (pi is generally default). If you choose another username than yourself, you will have to run with sudo. (source)

Add the following line:

@reboot /usr/bin/sudo -u pi -H /usr/local/bin/forever start /usr/bin/homebridge

Save and exit. Confirm your change:

crontab -u pi -l

Troubleshooting

Forever worked straight out of the box for me; however, the startup task took some work. Running $ homebridge would work but running $ sudo homebridge would end with an error as it could not find the ~/.homebridge/config.json file. From what I remember, because the startup launch uses sudo it expected to find config.json in a different directory than it was in. I put a bandaid on this by making a symlink from the real file to where it was expecting one.

ln -s ~/.homebridge/config.json /path/to/where/it/wants/config.json

Homebridge Setup

The Configuration file

Homebridge’s config.js is what defines the /accessories/ that is creates. For me, I need a 5 input radio button / multi-switch and simple binary on/off switch. I also need these switches to make http requests when they are triggered. There were no options to do this when I started this so I wrote a basic switch plugin for this: homebridge-switcheroo. This is my first time writing Javascript so it may be shit, but that’s why it has an MIT license, you can go make it better.

Install homebridge-switcheroo

npm install -g homebridge-switcheroo

Update your config file

Read this section of the switcheroo wiki . Here’s a sample config.json:

{
   "bridge":{
      "name":"Homebridge",
      "username":"CC:22:3D:E3:CE:30",
      "port":51826,
      "pin":"000-00-000"
   },
   "accessories":[
      {
        "accessory": "Switcheroo",
        "switch_type": "Switch",
        "name": "Projector",
        "http_method": "GET",
        "base_url": "http://192.168.0.XXX/projector",
        "on_url": "/state/on",
        "off_url": "/state/off"
      },
      {
        "accessory": "Switcheroo",
        "switch_type": "Multiswitch",
        "name": "Switcher",
        "http_method": "GET",
        "base_url": "http://192.168.0.XXX/switcher/input",
        "multiswitch": [
           "Chromecast",
           "HDMI",
           "Raspberry Pi"
        ]
      }
   ]
}

And I’ll get around to writing the rest of this soon