Control DDC/CI capable monitors via MQTT

DDCMQTT is a little server program that sends DDC commands to monitors in response to MQTT messages. This allows you to, for example, change brightness and input from whatever custom scripts/hardware/control system you want.

I wrote it as an alternative approach to a custom bit of hardware I designed to do the same job (HDMI2C).

Running it

It should run on any Linux system which exposes monitor DDC via /dev/i2c-x. I use a Raspberry Pi 4 - it’s (relatively) cheap and has two micro hdmi ports, allowing control of two monitors.

Controlling it

I mean… the whole point is that you can bring your own control system. I have a 4x4 key keypad connected to the same Pi (as it happens) which I’ve written another small program for which listens to keystrokes and sends MQTT messages. I should write it up on here at some point.