Terma MOA Blue - Home Assistant Integration

Home Assistant custom integration for Terma MOA Blue electric heating elements via Bluetooth Low Energy (BLE).

This integration allows you to control Terma MOA Blue bathroom radiator heating elements directly from Home Assistant without requiring the official Terma BlueLine Next mobile app.

Features

✅ Full Control

• Turn heating on/off
• Set target temperature (30-60°C for element, 15-30°C for room)
• Real-time temperature monitoring
• LED temperature indicator support

✅ Native Home Assistant Integration

• Climate entity for easy control
• Temperature sensor entities
• Lovelace thermostat card compatible
• Automation support

✅ Reliable Bluetooth Communication

• Automatic device discovery
• Multiple retry attempts for stable connection
• Proper BLE pairing support
• Works with Bluetooth adapters and ESPHome Bluetooth proxies

Compatibility

Supported Devices

• Terma MOA Blue electric heating elements (models with Bluetooth)
• Firmware: Tested with devices from 2023-2024

Requirements

• Home Assistant 2024.1.0 or newer
• Bluetooth adapter with BLE support OR ESPHome Bluetooth proxy
• Python 3.11+

Installation

HACS (Recommended)

1. Open HACS in Home Assistant
2. Go to "Integrations"
3. Click the three dots (⋮) in the top right
4. Select "Custom repositories"
5. Add repository URL: https://github.com/johnfromul/terma_moa_blue
6. Category: Integration
7. Click "Add"
8. Click "Install" on the Terma MOA Blue integration
9. Restart Home Assistant

Manual Installation

1. Download the latest release
2. Extract the terma_moa_blue folder to your custom_components directory:

   config/
   └── custom_components/
       └── terma_moa_blue/
           ├── __init__.py
           ├── manifest.json
           ├── ...
   

3. Restart Home Assistant

Setup

Step 1: Bluetooth Pairing

Important: Terma MOA Blue devices require Bluetooth pairing before use.

Put Device in Pairing Mode

1. Press and hold the button on the heating element for 5 seconds
2. The blue LED will start blinking (pairing mode active for 30 seconds)

Pair via Home Assistant Terminal

# Open Home Assistant terminal (SSH or Terminal & SSH add-on)
bluetoothctl

# Disable scanning to stop log spam
scan off

# Pair with your device (replace with your MAC address)
pair CC:22:37:11:47:6D

# Enter PIN when prompted
123456

# Trust the device
trust CC:22:37:11:47:6D

# Verify pairing
paired-devices

# Exit
quit

$\color{red}{\text{!!! if you have a problem in the terminal with unstopable ads scanning}}$

make a easy bash script \config\terma_pair.sh with this code:

#!/bin/bash

# Switch the heating element into pairing mode!
echo "!!! SWITCH THE HEATING ELEMENT INTO PAIRING MODE (5s hold button with temp. icon, blue
LED slow blink) !!!"
echo "You have 30 seconds..."
sleep 10

{
  sleep 2
  echo "agent KeyboardDisplay"
  sleep 1
  echo "default-agent"
  sleep 1
  echo "pair CC:22:37:11:48:0D"
  sleep 3
  echo "123456"
  sleep 5
  echo "trust CC:22:37:11:48:0D"
  sleep 2
  echo "quit"
} | bluetoothctl
EOF

Restart Home Assistant

ha core restart

Step 2: Add Integration

1. Go to Settings → Devices & Services
2. Click + Add Integration
3. Search for "Terma MOA Blue"
4. Select your heating element from the discovered devices
5. Click Submit

The integration will create:

• 1 Climate entity (thermostat)
• 2 Temperature sensor entities (current room, current element)

Usage

Via Lovelace UI

Add a thermostat card to your dashboard:

type: thermostat
entity: climate.terma_wireless_element

Via Services

Turn on heating:

service: climate.set_hvac_mode
target:
  entity_id: climate.terma_wireless_element
data:
  hvac_mode: heat

Set temperature:

service: climate.set_temperature
target:
  entity_id: climate.terma_wireless_element
data:
  temperature: 50

Turn off:

service: climate.set_hvac_mode
target:
  entity_id: climate.terma_wireless_element
data:
  hvac_mode: "off"

Automation Example

Heat bathroom before morning shower:

automation:
  - alias: "Morning Bathroom Heat"
    trigger:
      - platform: time
        at: "06:00:00"
    action:
      - service: climate.set_hvac_mode
        target:
          entity_id: climate.terma_wireless_element
        data:
          hvac_mode: heat
      - service: climate.set_temperature
        target:
          entity_id: climate.terma_wireless_element
        data:
          temperature: 55
      - delay:
          minutes: 30
      - service: climate.set_hvac_mode
        target:
          entity_id: climate.terma_wireless_element
        data:
          hvac_mode: "off"

Configuration

Temperature Ranges

• Element Temperature: 30-60°C (radiator heating element)
• Room Temperature: 15-30°C (ambient room temperature)

Update Interval

The integration polls the device every 120 seconds (2 minutes) to preserve battery life and BLE connection stability.

LED Temperature Indicator

The heating element's LED bars indicate the current target temperature:

• 1 bar: 30-37°C
• 2 bars: 38-43°C
• 3 bars: 44-49°C
• 4 bars: 50-55°C
• 5 bars: 56-60°C

Troubleshooting

Device Not Discovered

1. Check Bluetooth range: Ensure heating element is within range of your Bluetooth adapter
2. Put device in pairing mode: Blue LED should be blinking
3. Check logs: Settings → System → Logs, filter by terma_moa_blue

Connection Errors

Error: failed to discover services, device disconnected

Solution: Device is not paired. Follow the Bluetooth pairing steps above.

Error: ATT error: 0x0e (Unlikely Error)

Solution: Authentication failed. Remove old pairing and pair again:

bluetoothctl
remove CC:22:37:11:47:6D
# Then follow pairing steps again

Heating Not Starting

1. Verify device is powered (connected to mains)
2. Check wattmeter: should show ~600W when heating
3. Enable debug logging (see below)
4. Check that heating mode is set correctly

Debug Logging

Enable detailed logging in configuration.yaml:

logger:
  default: info
  logs:
    custom_components.terma_moa_blue: debug

Restart Home Assistant and check the logs.

Technical Details

Protocol Reverse Engineering

This integration was developed through reverse engineering of the Terma BlueLine Next mobile app using Frida instrumentation.

Key findings:

• Device uses Bluetooth Low Energy (BLE) GATT protocol
• Service UUID: d97352b0-d19e-11e2-9e96-0800200c9a66
• Operating modes: 0x20 (OFF), 0x21 (ON)
• Temperature format: Little-endian 16-bit integer (value × 10)
• Requires Bluetooth pairing with PIN 123456

BLE Characteristics

UUID	Function	Format
d97352b1	Room temperature	[current_low, current_high, target_low, target_high]
d97352b2	Element temperature	[current_low, current_high, target_low, target_high]
d97352b3	Operating mode	[mode, 0x00, 0x00, 0x00]

Development

Project Structure

custom_components/terma_moa_blue/
├── __init__.py          # Integration setup
├── manifest.json        # Integration metadata
├── config_flow.py       # Configuration flow
├── const.py            # Constants and enums
├── coordinator.py      # Data update coordinator
├── api.py             # BLE communication layer
├── climate.py         # Climate entity
└── sensor.py          # Sensor entities

Contributing

Contributions are welcome! Please:

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Add tests if applicable
5. Submit a pull request

Reverse Engineering Process

The protocol was reverse-engineered using:

• Frida instrumentation framework
• Android app decompilation (JADX)
• BLE packet capture (Wireshark)
• Runtime hooking of Bluetooth GATT operations

See Frida scripts for details.

Credits

• Developer: @johnfromul
• Assistant: Claude (Anthropic) - Protocol analysis and integration development
• Manufacturer: Terma

License

MIT License - see LICENSE file for details.

Disclaimer

This is an unofficial integration not affiliated with or endorsed by Terma. Use at your own risk.

The integration was developed through reverse engineering for personal use and educational purposes. All trademarks belong to their respective owners.

Support

• Issues: GitHub Issues
• Discussions: GitHub Discussions

Changelog

See CHANGELOG.md for version history.

Related Projects

• Home Assistant
• HACS
• Bleak - BLE library
• ESPHome Bluetooth Proxy

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