Unit AMeter Home Assistant Integration

ads1115:
  - address: 0x48

sensor:
  - platform: ads1115
    multiplexer: "A0_A1"
    gain: 0.256
    sample_rate: 128
    name: "Unit AMeter A0_A1 Ref"
    id: diff
    update_interval: 10s

i2c_device:
  id: eeprom
  address: 0x51

sensor:
  # Previous ads1115 declarations
  ...
  - platform: template
    name: "Input Current"
    id: input_cur
    unit_of_measurement: "A"
    icon: "mdi:current-dc"
    accuracy_decimals: 2
    update_interval: 10s
    lambda: |-
      float d = id(diff).state;

      if (isnan(d)) return NAN;

      const float PRESSURE_COEFF = 0.05f;

      const uint8_t EEPROM_REG = 0xF8;

      uint8_t calib[8];
      uint16_t hope, actual;

      if ( id(eeprom).read_register(EEPROM_REG, calib, 8) != i2c::ERROR_OK ) {
        ESP_LOGD("ameter.sensor", "Failed to read from EEPROM..");
        return NAN;
      }

      uint8_t xor_result = 0x00;

      for (uint8_t i = 0; i < 5; i++) {
          xor_result ^= calib[i];
      }

      if (xor_result != calib[5]) {
        return NAN;
      }

      hope   = (calib[1] << 8) | calib[2];
      actual = (calib[3] << 8) | calib[4];

      float calibration_ratio = (float)hope / actual;

      ESP_LOGD("ameter.sensor", "Factory calibration factor: %f", calibration_ratio);

      float ain = - d / PRESSURE_COEFF;

      ain = ain * calibration_ratio;

      return ain;

// In lambda expression
// remember to change the 'EEPROM_REG' if you changed the 'gain'
// for an example, when 'gain' is 0.256
const uint8_t EEPROM_REG = 0xF8;