MAX31865 Platinum RTD Temperature Sensor

The max31865 temperature sensor allows you to use your max31865 RTD temperature sensor (datasheet) with ESPHome


MAX31865 Sensor. Image by Adafruit

As the communication with the MAX31865 is done using SPI, you need to have an spi bus in your configuration with both miso_pin and mosi_pin set.

  • VIN connects to 5V (3V3 will output 3.3V), or directly connect 3V3 to 3.3V

  • 3Vo is not used by ESPHome

  • GND connects to ground

  • CLK connects to the SPI clk_pin

  • SDO connects to the SPI miso_pin

  • SDI connects to the SPI mosi_pin

  • CS connects to a free GPIO pin

  • RDY is not used by ESPHome

# Example configuration entry
  miso_pin: D0
  mosi_pin: D1
  clk_pin: D2

  - platform: max31865
    name: "Living Room Temperature"
    cs_pin: D3
    reference_resistance: 430 Ω
    rtd_nominal_resistance: 100 Ω

Configuration variables:

  • name (Required, string): The name for the temperature sensor.

  • cs_pin (Required, Pin Schema): The Chip Select pin of the SPI interface.

  • update_interval (Optional, Time): The interval to check the sensor. Defaults to 60s.

  • reference_resistance (Required, float): Reference resistor on the PCB. Adafruit’s PT100 (#3328) uses 430 Ω, their PT1000 (#3648) uses 4300 Ω.

  • rtd_nominal_resistance (Required, float): Nominal resistance of the RTD at 0°C. PT100 is 100 Ω, PT1000 is 1000 Ω.

  • mains_filter (Optional, string): The mains power frequency to reject (50 Hz or 60 Hz). Defaults to 60 Hz.

  • rtd_wires (Optional, int): The number of RTD wires. Be sure to solder board jumpers to match! Defaults to 4.

  • spi_id (Optional, ID): Manually specify the ID of the SPI Component if you want to use multiple SPI buses.

  • id (Optional, ID): Manually specify the ID used for code generation.

  • All other options from Sensor.

See Also