IoTLabs wM-Bus Gateway is an ESP32 device supporting the Wireless M-Bus (wM-Bus) standard for receiving data from compatible meters and sensors, designed for full integration with Home Assistant.
Wireless M-Bus (Wireless Meter Bus) is a wireless protocol specifically designed for remote reading of smart meters, generally gas, water, or electricity meters, and typically used by utilities, but the wM-Bus gateway allows you to deploy the standard for your home automation solution, meters, and sensors.
wM-Bus gateway specifications:
- Main controller – ESP32 dual-core microcontroller with Wi-Fi and BLE connectivity
- Display – 1.3-inch OLED for live measurements and status
- wM-Bus –
- 868 MHz radio receiver; Semtech SX1276-based RFM95/RFM96 according to the code
- Supports T1 and C1 frames, compatible with the wmbusmeters library
- Antennas
- Built-in 2.4 GHz antenna for Wi-Fi and Bluetooth
- External SMA antenna for wireless M-Bus; important: must be connected before powering the device to avoid damage
- Misc
- Top button to switch pages on the display.
- Bottom button to reset the device.
- Built-in LED
- Power Supply – 5V DC via microUSB port
- Dimensions – 70 × 36 × 15 mm
The firmware integrates wmbusmeters, ESPHome, and custom-made code. You’ll find the source code and binary releases on GitHub. The firmware can be flashed through the web tools on IoTLabs server, which include a Flasher, as well as Improv BLE and Serial to set the WiFi credentials over Bluetooth or USB.
The GitHub repo also includes the blueprint.yaml configuration file for ESPHome, which you can modify to match your requirements if needed.
ESPHome compatibility enables full integration with Home Assistant. The built-in 1.3-inch OLED display shows the following information by default:
- Measurements received from meters
- Current device status: Wi-Fi connection, signal strength, reception status
- Most recent activity and radio transmission parameters
The gateway can also be configured as a Bluetooth proxy, and forward data from BLE sensors to Home Assistant, at the same time as supporting wM-Bus data reception. The gateway can publish data to MQTT, native API, REST endpoints, or TCP/UDP sockets.
Besides reading meter data, the wM-Bus gateway can be integrated with utility billing systems, collect real-time data for automation and charts, used for local analysis of unusual consumption, such as leak detection. Additional information may be found on the product page.
The wM-Bus gateway can be purchased for about $50 on Lectronz or Tindie. Note that wM-Bus is mostly a European standard, although some other countries like India and Russia are also using it at the same ~868 MHz frequency, and others at 433 MHz. The US meters apparently rely on proprietary AMR (Automatic Meter Reading) systems, often operating over the 915 MHz band.
Jean-Luc started CNX Software in 2010 as a part-time endeavor, before quitting his job as a software engineering manager, and starting to write daily news, and reviews full time later in 2011.
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