esphome-sensostar

Custom ESPHome Component for Engelmann SensoStar Heat Meters

This ESPHome integration enables reading detailed heat consumption data from Engelmann SensoStar U heat meters and makes it available in Home Assistant.

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🔧 Features

• 📊 Sensor Readings

  • Energy consumption (kWh)
  • Flow rate (m³/h)
  • Volume (m³)
  • Power (W)
  • Flow temperature (°C)
  • Return temperature (°C)
  • Temperature difference (ΔT)
  • Meter status (text)
  • Battery voltage (via ADC)

• 🧠 Home Assistant Integration

  • Native API support
  • OTA updates
  • Web dashboard (optional)

• 🕹 Controls

  • Template button in Home Assistant for instant battery reading
  • Template button in Home Assistant for instant Wi-Fi signal strength reading

• 💡 LED Indicators

  • Flash programming
  • Wi-Fi connection status
  • Heartbeat (device activity)
  • New data received from the SensoStar meter

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🧪 Requirements

• ESP32-S3 DevKitC-1 (8MB Flash)
• ESPHome installed on your system
• Home Assistant (optional but recommended)
• Sensostar Heatmeter the following have been confirmed to be working
  • SensoStar U (Engelmann)
  • SensoStar E (Engelmann)
  • Volumess VI E (Wasser-Geräte)
  • microCLIMA EVO (Maddalena)
  • microCLIMA U (Maddalena)
  • Brummerhoop F90U3
  • Molline Wingman C3

Check compatibility: Only uints with Modul are working.

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🔌 Hardware Wiring

The SensoStar meter uses a 12-pin internal connector for communication and power. Below is the pinout and how to wire it to an ESP32-S3:

Pin	Function	Connection
1	NC	—
2	GND	Connect to ESP32 GND
3	VCC	Connected to the internal battery of the meter
4	NC	—
5	RX	Connect to ESP32 UART TX
6	TX	Connect to ESP32 UART RX
7	NC	—
8	NC	—
9	NC	—
10	HW Detect (56kΩ to GND)	Connect a 56kΩ resistor to GND
11	NC	—
12	GND	Connect to ESP32 GND

Note: "NC" means Not Connected. Be sure to use level shifting or protective circuitry if needed, depending on your ESP32 model and power requirements.

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📷 Example Hardware

Below is a visual example of the wired hardware setup.

Image

Version 1 (black PCB)

Version 2 (red PCB)

Web-Interface

Homeassistant-Interface

Schematics

Version 1 (black PCB)

Version 2 (red PCB)

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🚀 Setup Instructions

1. Install ESPHome
   ESPHome installation guide

2. Clone or reference this repository in your ESPHome config:

   external_components:
     - source:
         type: git
         url: https://github.com/STB3/esphome-sensostar
       components: [ SensoStar_MBus ]

3. Create a secrets.yaml file in the same folder as your ESPHome config file (sensostar.yaml):

   # secrets.yaml
   wifi_ssid: "YourSSID"
   wifi_password: "YourPassword"
   api_encryption_key: "YourAPIKey"  # Generate with: openssl rand -base64 32

   Generate the key online

4. Build and upload your firmware:

Black PCB

cd path\to\your\config
esphome run sensostar_black.yaml

Red PCB

cd path\to\your\config
esphome run sensostar_red.yaml

5. Fallback in case no credential were found

   You can then access the device's web interface at the default IP address 192.168.4.1 and enter your SSID and password

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📦 Repository Contents

• components/SensoStar_MBus/: Custom ESPHome component for the SensoStar M-Bus meter
• No user-specific configuration files are committed (e.g. sensostar.yaml or secrets.yaml)

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🔐 Security Note

This repository does not contain any private configurations. Be sure to:

• Use secrets.yaml to keep credentials out of your main config
• Add .gitignore rules to exclude secrets from being committed

# .gitignore
secrets.yaml
*.key
*.pem

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📫 Contact

Maintained by STB3
For issues or feature requests, open an issue in the GitHub repository.

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📝 License

This project is open-source and licensed under the MIT License.