IHC MQTT Bridge

This script acts as a bridge between an IHC system and an MQTT broker, enabling Home Assistant to control and monitor IHC-based outputs and inputs via MQTT.

It connects to the IHCServer using a WebSocket and exposes all input/output states over MQTT. It also listens for MQTT commands to control outputs on the IHC system. This makes it possible to integrate older Danish IHC systems into modern smart home platforms like Home Assistant.

The bridge runs on a Raspberry Pi alongside the IHCServer and is resilient, logging all activity and reconnecting automatically in case of failures.

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What You'll Need

• A Raspberry Pi - I used an old Rpi 1 so any model will do
• USB to RS485 adapter (often available on AliExpress for ~$1, and they usually work fine)
• IHC controller
• Installed and running IHCServer
• MQTT broker (e.g., EMQX installed via the Home Assistant Add-on store)
• Home Assistant (optional, but recommended)

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Installation

1. Follow these guides to get your IHC server up and running:

   • USB to RS485 dongle configuration
   • IHCServer setup guide

2. Clone this repository to the /opt folder:

   cd /opt
   git clone https://github.com/JAQ0B/IHCBridge.git
   
   

3. Install required Python packages

   Run the following commands to install the dependencies in a vertual environment:

   # Install venv if you don’t have it
   sudo apt update
   sudo apt install python3-venv
   
   # Navigate to the project folder
   cd /opt/IHCBridge
   
   # Create a virtual environment
   python3 -m venv venv
   
   # Activate the virtual environment
   source venv/bin/activate
   
   # Install dependencies inside the virtual environment
   pip install -r requirements.txt
   

4. Edit IHCBridge.py to match your setup

   Open the file and change the following:

   • self.ihc_host: Set this to the IP address of the device running the IHCServer (usually the same Pi).

   • self.mqtt_host: Set this to the IP address of your MQTT broker.

   • If your MQTT credentials differ from the default, update the line:

     self.mqtt_client.username_pw_set("USERNAME", "PASSWORD")
     

     Or remove it if your broker doesn’t require authentication.

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🔄 Daemon Setup (Auto-start on Boot)

Create systemd service files

1. Create the service file for the IHC MQTT Bridge

   File path: /etc/systemd/system/ihc-bridge.service

   [Unit]
   Description=IHC MQTT Bridge
   After=network.target
   
   [Service]
   ExecStart=/opt/IHCBridge/venv/bin/python /opt/IHCBridge/IHCBridge.py
   Restart=always
   RestartSec=10
   
   [Install]
   WantedBy=multi-user.target
   

2. Create the service file for the IHCServer

   File path: /etc/systemd/system/ihcserver.service

   [Unit]
   Description=IHC server daemon
   
   [Service]
   Type=simple
   ExecStart=/opt/ihcserver/ihcserver -d
   StandardOutput=null
   Restart=always
   RestartSec=2
   
   [Install]
   WantedBy=sysinit.target
   

3. Enable and start both services

   Run the following commands:

   sudo systemctl daemon-reexec
   sudo systemctl daemon-reload
   sudo systemctl enable ihcserver
   sudo systemctl enable ihc-bridge
   sudo systemctl start ihcserver
   sudo systemctl start ihc-bridge
   

4. View the IHC Bridge log if needed

   Use this command to tail the log file:

   tail -f /opt/ihc_bridge.log
   

🏠 Home Assistant Integration

1. Set up MQTT

• Install the EMQX broker from the Home Assistant Add-on store.
• Use the MQTT integration in Home Assistant to connect to your EMQX broker.

2. Configure Home Assistant YAML

In your configuration.yaml file, add:

mqtt:
  switch: !include mqtt_switches.yaml
  light: !include mqtt_lights.yaml
  binary_sensor: !include mqtt_binary_sensors.yaml

This tells Home Assistant to load switches, lights, and binary sensors from separate files for better organization.

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3. Create the YAML files

Create separate files for different device types:

• mqtt_switches.yaml for switches
• mqtt_lights.yaml for lights
• mqtt_binary_sensors.yaml for inputs (sensors, buttons, etc.)

Each output (light or switch) must be manually added based on your IHC module layout.

Output Examples (Switches & Lights):

# Module 1, Output 2 example
- unique_id: ihc_output_1_2
  name: "Dinner Table"
  state_topic: "ihc/outputState/1/2/state"
  command_topic: "ihc/output/1/2/set"
  payload_on: "ON"
  payload_off: "OFF"

Input Examples (Binary Sensors):

Note: Input support is implemented in the bridge code but has not been personally tested. It should work based on the code implementation.

# Module 1, Input 3 - Motion Sensor example
- unique_id: ihc_input_1_3
  name: "Living Room Motion"
  state_topic: "ihc/inputState/1/3/state"
  payload_on: "ON"
  payload_off: "OFF"
  device_class: motion

# Module 1, Input 4 - Door Contact example  
- unique_id: ihc_input_1_4
  name: "Front Door"
  state_topic: "ihc/inputState/1/4/state"
  payload_on: "ON"
  payload_off: "OFF"
  device_class: door

# Module 2, Input 1 - Push Button example
- unique_id: ihc_input_2_1
  name: "Hallway Button"
  state_topic: "ihc/inputState/2/1/state"
  payload_on: "ON"
  payload_off: "OFF"

Key Differences Between Outputs and Inputs:

Outputs (Switches/Lights):

• State topic: ihc/outputState/{module}/{output}/state
• Command topic: ihc/output/{module}/{output}/set (for sending commands)
• Use switch or light in Home Assistant

Inputs (Binary Sensors):

• State topic: ihc/inputState/{module}/{input}/state
• No command topic (read-only)
• Use binary_sensor in Home Assistant
• Can use device classes like motion, door, window, button, etc.

Configuration Parameters:

• unique_id: Should be globally unique. Recommended format: ihc_output_<module>_<number> for outputs, ihc_input_<module>_<number> for inputs.
• name: The friendly name shown in the Home Assistant UI.
• state_topic: The MQTT topic the bridge uses to publish the current state.
• command_topic: The topic that sends commands back to the bridge (outputs only).
• payload_on / payload_off: Strings to represent on/off states.
• device_class: For binary sensors, use appropriate classes for better UI icons and behavior.

Repeat for all relevant outputs and inputs by adjusting the module/output/input numbers and names.

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4. Restart Home Assistant

After saving the YAML files, restart Home Assistant.
You should now see all of your IHC devices appear as native entities in the dashboard.

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📌 Notes

• The bridge reconnects automatically and handles failure cases (MQTT down, IHC server restart, etc.).
• You can also trigger IHC or Raspberry Pi restarts via MQTT by sending "RESTART" to:
  • ihc/system/restart – restarts IHC server
  • ihc/system/pi_restart – reboots the Pi

These can be used in Home Assistant automations or manually via MQTT.

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🔒 License

This project is licensed under the MIT License.
See the LICENSE file for details.

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💬 Contributions

This project is shared to help others integrate IHC with Home Assistant.
While it’s not actively developed, pull requests and improvements are always welcome!