cec-mqtt-bridge

A HDMI-CEC and IR to MQTT bridge written in Python 3 for connecting your AV-devices to your Home Automation system. You can control and monitor power status and volume.

Features

• HDMI-CEC
  • Power control and feedback
  • Volume control (up/down/specific) and feedback
  • Relay HDMI-CEC messages from HDMI to broker (RX)
  • Relay HDMI-CEC messages from broker to HDMI (TX)
• IR
  • Relay IR keypresses from IR to broker (RX)
  • Relay IR keypresses from broker to IR (TX)

Dependencies

• MQTT broker (like Mosquitto)

  • "apt-get install mosquitto"

• python paho-mqtt module

  • https://eclipse.dev/paho/files/paho.mqtt.python/html/client.html
  • "apt-get install python3-paho-mqtt"

• python HDMI-CEC module

  • libcec4 with python bindings (https://github.com/Pulse-Eight/libcec)
  • NOTE: cec python package is not available on pypi
    • "apt-get install python3-cec" OR compile the bindings yourself
  • HDMI-CEC interface device (like a Pulse-Eight device, or a Raspberry Pi)

• python LIRC module

  • lirc with python bindings (https://www.lirc.org/api-docs/html/group__python__bindings.html)
  • NOTE: lirc python package is not available on pypi
    • "apt-get install lirc"
    • "sudo pip install /usr/share/lirc/lirc-*.tar.gz" see #18
    • OR compile & install https://sourceforge.net/p/lirc/git/ci/master/tree/python-pkg/

• lircd + hardware to receive and send IR signals

  • cheep IR RX and TX with transistor https://www.aliexpress.us/item/2251801744452143.html
  • to get RX and TX working see raspberrypi/linux#2993 (comment)

Install on Raspbian bullseye

If there is not a MQTT broker already on your network

sudo apt-get install mosquitto

Install python dev packages, lirc, cec & paho-mqtt modules

sudo apt-get update
sudo apt-get install build-essential git lirc python3 python3-dev python3-setuptools python3-pip python3-wheel python3-build python3-venv python3-paho-mqtt python3-cec
sudo pip install /usr/share/lirc/lirc-*.tar.gz
git clone https://github.com/michaelarnauts/cec-mqtt-bridge.git
cd cec-mqtt-bridge/
./contrib/debian-ubuntu-install.sh
sudo vi /etc/cec-mqtt-bridge.ini
sudo systemctl restart cec-mqtt-bridge

to update

cd cec-mqtt-bridge/
git pull
./contrib/debian-ubuntu-install.sh

MQTT Topics

The bridge subscribes to the following topics:

topic	body	remark
prefix/cec/device/laddr/power/set	on / standby	Turn on/standby device with with logical address laddr (0-14).
prefix/cec/device/laddr/active/set	yes / no	activate/deactivate device with with logical address laddr (0-14).
prefix/cec/audio/volume/set	integer (0-100) / up / down	Sets the volume level of the audio system to a specific level or up/down.
prefix/cec/audio/mute/set	on / off	Mute/Unmute the the audio system.
prefix/cec/tx	commands	Send the specified commands to the CEC bus. You can specify multiple commands by separating them with a space. Example: cec/tx 15:44:41,15:45.
prefix/ir/remote/tx	key	Send the specified key of remote to the IR transmitter.

The bridge publishes to the following topics:

topic	body	remark
prefix/bridge/status	online / offline	Report availability status of the bridge.
prefix/cec/device/laddr/type	on / off	Report type of device with logical address laddr (0-14).
prefix/cec/device/laddr/address	on / off	Report physical address of device with logical address laddr (0-14).
prefix/cec/device/laddr/active	yes / no	Report active source status of device with logical address laddr (0-14).
prefix/cec/device/laddr/vendor	string	Report vendor of device with logical address laddr (0-14).
prefix/cec/device/laddr/osd	string	Report OSD of device with logical address laddr (0-14).
prefix/cec/device/laddr/cecver	string	Report CEC version of device with logical address laddr (0-14).
prefix/cec/device/laddr/power	on / standby / toon / tostandby / unknown	Report power status of device with logical address laddr (0-14).
prefix/cec/device/laddr/language	string	Report langauge of device with logical address laddr (0-14).
prefix/cec/audio/volume	integer (0-100) / unknown = 127	Report volume level of the audio system.
prefix/cec/mute/status	on / off	Report mute status of the audio system.
prefix/cec/rx	command	Notify that command was received.
prefix/ir/remote/rx	key	Notify that key of remote was received. You have to configure key AND remote as config in the lircrc file.
prefix/ir/rx	key	Notify that key was received. You have to configure key in the lircrc file. This format is used if the remote is not given in the config file.

id is the address (0-15) of the device on the CEC-bus.

Examples

• mosquitto_pub -t media/cec/volup -m ''
• mosquitto_pub -t media/cec/tx -m '15:44:42,15:45'

Configuration

You can either copy config.default.ini to config.ini and adjust its properties, or alternatively declare any of those as environment variables using the format SECTION_KEY (e.g., MQTT_USER).

Interesting links

• https://github.com/nvella/mqtt-cec
• http://www.cec-o-matic.com/
• https://kwikwai.com/knowledge-base/the-hdmi-cec-bus/
• https://www.hdmi.org/docs/Hdmi13aSpecs
• https://github.com/Pulse-Eight/libcec/blob/master/include/cec.h
• https://github.com/Pulse-Eight/libcec/blob/master/src/pyCecClient/pyCecClient.py