This is some simple code to allow turning on and off lights via my Raspberry Pi with the purpose of connecting to IFTTT (if this, then that) so you can trigger lights on a variety of events such as time of day, a button press on your phone, or when you enter or leave an area.

My hardware setup: serial pins 5 (ground) and 7 (RTS, changed between high/low voltage) are connected to a triac (SSRAC112) and then to the wall (through a fuse and a couple switches) and the lights.

This is inspired by my bell system. I had some hardware sitting around from that project and decided I might as well put it to use.

Update your nginx config to point to the lights Tornado instance we'll set up at a particular subdirectory (make sure it matches the "root" option in your config file):

http {
    upstream lights {
        server 127.0.0.1:8080;
    }

    ...

    server {
        ...

        location /lights/ {
            proxy_pass_header Server;
            proxy_set_header Host $http_host;
            proxy_redirect off;
            proxy_set_header X-Real-IP $remote_addr;
            proxy_set_header X-Scheme $scheme;
            proxy_pass http://lights;
        }

        ...
    }
}

Restart nginx:

$ sudo systemctl restart nginx

Install program to /usr/bin, config to /etc, systemd script to /etc/systemd/system, etc.

$ makepkg -si

Then make sure you edit /etc/lights.yaml changing the key, port, etc. To enable and run:

$ sudo systemctl enable lights
$ sudo systemctl start lights

Check and add yourself to the groups for your serial ports in /dev:

$ ls -l /dev | grep tty
...
crw-rw---- 1 root uucp   188,   0 Oct 21 19:41 ttyUSB0
...
$ sudo usermod -a -G uucp your_username
$ logout # Only takes effect when you log back in

Install dependencies:

$ pip install tornado pyyaml pyserial

Copy the config file and make your desired changes, making sure to change the key:

$ cp config.yaml my_config.yaml
$ vim my_config.yaml # ...

Edit the lights.service file setting the path to the Python file and config and desired user/group you want it to run as, then install via:

$ sudo cp lights.service /etc/systemd/system/
$ sudo chown root:root /etc/systemd/system/lights.service
$ sudo systemctl enable lights
$ sudo systemctl start lights

To make this easy to use on your phone, install IFTTT (if this, then that). Then, for example, you can create a widget for your homescreen that will toggle your lights:

• Enable webhooks
• Go to "My Applets" (center button at bottom) in the app
• Click top "+" icon to add your own applet
• Make this a "button widget"
• Make that a webhook with "https://example.com/lights/hook?action=toggle&key=..."
• Add the IFTTT button widget to your homescreen and select this applet to trigger on press

Alternatively, you could turn on/off (change action to "on" or "off") your lights when you exit an area (or similarly enter) by searching for "location" or make it turn on/off at a certain time searching for "date & time".

Monitor the output of Tornado for debugging, verifying that it's receiving the on/off/toggle requests correctly:

$ sudo journalctl -u lights.service -f