This repository contains a PCB and housing that can be used as the hardware to read the measurements from a Kamstrup Multical 403. The PCB uses a 'D1 Mini' ESP8266 board. A software component for use in ESPHome has been created.

Using this setup you can read measurements from the Kamstrup Multical (e.g. city heating) and publish the measurements to Home Assistant.

The Kamstrup Multical 403 uses an optical interface for communication. A PCB was designed that uses a mini-D1 ESP8266 board. The PCB Gerbers folder contains the required files to fabricate the PCB. The PCB Components folder contains the BOM (bill of materials) and the component placement files. A special version for use with JLCBCB has been created for these.

The PCB has the following features:

• Optical interface for use with the Kamstrup meter
• Pulse counter (can be used with a proximity sensor to measure water consumption)
• 2 free open collector outputs
• 2 free inputs

• Order (or build) the PCB with the transistors and resistors
• IR LED 940 nm
• IR Photo Diode 940 nm
• D1 Mini ESP8266 board
• Optional: Header pins

The housing can be 3D printed with a regular 3D printer. The Fusion 360 design and STL files are provided.

The Kamstrup Multical 40x meter needs to be waken up by pressing a button. It then stays awake for a few minutes. To keep the meter awake, magnets must be placed in the 4 holes. Every hole fits 2 magnets (using a total of 8).

• PCB printer to print the 2 STL files (housing and lid)
• 8x 6x3 mm neodymium magnets

Use the kamstrup_kmp component in ESPHome. Refer to the Documentation for all details regarding this component.

Example config file:

uart:
  baud_rate: 1200
  stop_bits: 2
  tx_pin: GPIO15
  rx_pin: GPIO13

sensor:
  - platform: kamstrup_mc40x
    heat_energy:
      name: 'Heat Energy'
    power:
      name: 'Heat Power'
    temp_diff:
      name: 'Heat Temperature Difference'
    flow:
      name: 'Heat Flow'
    custom:
      - name: Custom Heat Energy
        command: 0x003C
      - name: Custom Heat Power
        command: 0x0050
    update_interval: 60s