friedrich-hass

This is a simple HomeAssistant integration for Friedrich Chill series air conditioners (and maybe others that use the same IR protocol). Includes Arduino code for a Teensy LC and a custom component for HomeAssistant to send commands to the Teensy to control the AC.

How it works

The commands sent by Friedrich's remote are idempotent - that is, they include all the information about the state of the air conditioner. Rather then sending a "temperature up" command, the remote sends a "set the temperature to 75 degrees." The OEM remote is stateful, and keeps track of the total state of the air conditioner. Because of this, it's actually quite easy for us to control the AC some other way - we don't need to ask the AC what it's state is, because our commands will set the state to exactly what we want it to.

What works (and doesn't work)

Right now this supports setting the AC mode, temperature, and fan speed from HomeAssistant. Turning the AC on and off isn't actually supported yet (I just set the AC to Money Saver at 80 degrees when I leave my apartment).

Pull requests are welcome!

Setup / Installation

You'll need:

• A Teensy microcontroller (I used a Teensy LC)
• An Infrared LED and appropritate current limiting resistor
• A machine running HomeAssistant (mine is running in Docker on a Raspberry Pi)
• A USB A to Micro B cable

Hardware

Solder the LED and resistor to the appropriate transmit pin on the Teensy. The Teensy documentation has a table that indicates the correct pin to use. Put the Teensy somewhere that the infrared LED is pointed at the AC unit, and plug it with a micro USB cable.

Flash the Teensy with the Arduino sketch in the arduino folder, and test that it works by sending a remote command with the serial console.

HomeAssistant

Copy the friedrich_ir directory into the custom_components directory in your HomeAssistant config directory.

Plug the Teensy into the computer running HomeAssistant, and find out which TTY device it comes up as (mine is ttyACM0 on my Raspbian system). If you're running HomeAssistant in Docker, you'll need to pass this device into the container with the --device /dev/ttyACM0 option to docker run.

Add these lines to your HomeAssisant configuration.yaml, setting device to the correct TTY.

climate:
  - platform: friedrich_ir
    device: /dev/ttyACM0

Restart the HomeAssistant server, and you should now have climate controls!

Thanks

This was really easy for me to build, because Bryce Kahle did all the hard work of reverse engineering the IR protocol that Friedrich uses

Also a big shoutout to Fat Cat Fab Lab in NYC. If you live in New York and want to join an awesome community of makers, stop by and join us!