HX711 Load Cell Amplifier

The hx711 sensor platform allows you to use your HX711 load cell amplifier (datasheet, SparkFun_) with ESPHome

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HX711 Load Cell Amplifier. Image by SparkFun_ licensed and re-distributed under CC BY 2.0.

Connect GND to GND , VCC to 3.3V and the other two DOUT (or DT for short) and CLK (or SCK ) to free GPIO pins.

# Example configuration entry
sensor:
  - platform: hx711
    name: "HX711 Value"
    dout_pin: D0
    clk_pin: D1
    gain: 128
    update_interval: 60s

Configuration variables:

dout_pin (Required, Pin Schema): The DOUT (or DAT) pin.
clk_pin (Required, Pin Schema): The CLK pin.
gain (Optional, enum): The gain. Implicitly selects the channel. Defaults to 128 .
- 32 (Channel B, gain 32)
- 64 (Channel A, gain 64)
- 128 (Channel A, gain 128)
update_interval (Optional, Time): The interval to check the sensor. Defaults to 60s .
All other options from Sensor.

Converting Units

As the HX711 does not have any calibration data, you have to convert the measurement to units yourself. To calibrate the sensor:

Place a zero load or a known mass on the sensor, for example 0kg
Wait for the data to arrive in the logs and write down the value. For example 120 .
Place another (different) known mass on the sensor, for example 1kg
Again wait for the data to arrive and note the value, for example 810 .

Once you’ve done those steps, you can use the calibrate_linear filter to map the incoming value to the calibrated one:

# Example configuration entry
sensor:
  - platform: hx711
    # ... Other HX711 options
    filters:
      - calibrate_linear:
          - 120 -> 0
          - 810 -> 1
    unit_of_measurement: kg

Replace the masses and values 120.0 , 810.0 , etc with your values.