Module13.2 Dual Kmeter Temperature Sensor

Module13.2 Dual Kmeter is a dual-channel K-type temperature measurement module based on the "MAX31855KASA + stm32f030f4p6 + electrical isolation" solution. The module features two K-type thermocouple sensor interfaces, and uses a signal relay to alternately measure the temperature values of the two channels. It supports a measurement range of -200°C to 1350°C with an accuracy of ±2°C. Additionally, the module includes B0505LS-1WR2 and CA-IS3020S voltage and signal isolation chips, ensuring system stability and safety. The module also has a built-in DIP switch for easily switching different I2C addresses to meet various application needs. It can be used in industrial automation, instrument detection, and other scenarios.

This dual_kmeter sensor platform allows you to use the Module13.2 Dual Kmeter dual-channel K-Type thermocouple temperature module with ESPHome. The module exposes two independent thermocouple inputs (Kmeter 1 and Kmeter 2) as well as an on-board internal temperature sensor, all accessible over a single I²C bus.

The I²C Bus is required to be set up in your configuration for this sensor to work.

# Example configuration entry
i2c:
  sda: GPIO21
  scl: GPIO22

sensor:
  - platform: dual_kmeter
    name: "Thermocouple Channel 1"
    channel: KMETER_1
    update_interval: 60s

Configuration Variables

• channel (Required): The measurement channel to read. One of:

  Value	Description
  KMETER_1	K-Type thermocouple on input 1
  KMETER_2	K-Type thermocouple on input 2
  INTERNAL	On-board internal temperature sensor

• unit (Optional): The temperature unit reported by the sensor. One of CELSIUS or FAHRENHEIT. Defaults to CELSIUS.

• update_interval (Optional, Time): The interval at which the sensor is polled. Defaults to 60s.

• address (Optional, int): The I²C address of the module. Defaults to 0x11.

• All other options from Sensor.

Measurement Behavior

Thermocouple channels (KMETER_1 / KMETER_2)

When a thermocouple channel is selected, the component writes the channel selection register (0x20) on every update() cycle, then polls the ready-flag register (0x30) until the module signals that a fresh conversion is available. The component waits up to 300 ms; if the flag is not asserted within that window the update is skipped and a warning is logged:

[W][dual_kmeter]: Kmeter sampling timeout

Temperature values are stored in the module firmware as signed 32-bit integers in little-endian byte order, scaled by a factor of 0.01 (i.e. a register value of 2537 represents 25.37 °C).

Internal channel (INTERNAL)

The internal channel reads the module's on-board thermistor directly without waiting for a ready flag. This measurement is always available and is not affected by the thermocouple channel selection register.

I²C Address

The M5Stack Module Dual Kmeter uses a fixed I²C address of 0x11 by default. If the hardware address has been changed via the module's DIP switch, specify the new address with the address option:

sensor:
  - platform: dual_kmeter
    name: "Kiln Temperature"
    channel: KMETER_2
    address: 0x12        # non-default address

Full Configuration Example

i2c:
  sda: GPIO21
  scl: GPIO22

sensor:
  # --- Thermocouple channel 1, Celsius ---
  - platform: dual_kmeter
    name: "Kiln Thermocouple"
    channel: KMETER_1
    unit: CELSIUS
    update_interval: 30s
    filters:
      - sliding_window_moving_average:
          window_size: 5
          send_every: 5

  # --- Thermocouple channel 2, Fahrenheit ---
  - platform: dual_kmeter
    name: "Oven Thermocouple (°F)"
    channel: KMETER_2
    unit: FAHRENHEIT
    # for unit consistency, default 'unit_of_measurement' is celsius
    unit_of_measurement: "°F"  
    update_interval: 30s

  # --- On-board internal temperature ---
  - platform: dual_kmeter
    name: "Module Internal Temperature"
    channel: INTERNAL
    update_interval: 60s

An example of CoreS3 with Module13.2 Duak Kmeter:

See Also

• Sensor Filters
• I²C Bus
• M5Stack Module13.2 Dual Kmeter product page
• M5Stack Module13.2 Dual Kmeter Protocol