Automating an “old” TV

My Samsung TV is two years too old to receive automation commands over the LAN. Otherwise, my entire home theater experience is automated in openHAB, including my Yamaha receiver, my Tivo, and my Roku.

I was lamenting this to Noah Ternullo, and he said I could wire up an IR blaster. “Yeah,” I thought, “but that’s going to be really annoying.” It turned out to be really easy.

I already had this IR LED board from a previous project that used an Arduino, but I wanted it to work on a Raspberry Pi instead. I followed this writeup on how to configure LIRC on a Raspberry Pi to work with an IR LED driven by a GPIO pin. I gave my LED board 5V and GND and fed a control pin to it. Then I found a contributed lircd.conf for a very similar remote to my Samsung TV remote.

On the openHAB side, I added this item:

/* TV */
Switch TV_Power "TV Power" <switch> (media) { exec="OFF:ssh pi@raspberrypi.igo irsend SEND_ONCE Samsung_BN59-00685A KEY_POWER, ON:ssh pi@raspberrypi.igo irsend SEND_ONCE Samsung_BN59-00685A KEY_POWER" }

It uses the powerful exec binding to invoke a command from my openHAB server to the Pi. Now I have a power toggle for the TV. I put the private SSH key in /root/.ssh/ on the openHAB server and put the public key in /home/pi/.ssh/authorized_keys on the Pi to facilitate a passwordless connection.If you do this sort of thing yourself, remember that this is just a toggle. openHAB doesn’t really know if the TV’s on or off. In my case, I infer the TV’s state from the state of virtual buttons that I use to start or stop my media experience.

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