LTR390 UV and Ambient Light Sensor¶

The ltr390 sensor platform allows you to use your LTR390 UV and ambient light sensor (datasheet, Adafruit) with ESPHome.

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

sensor:
  - platform: ltr390
    uv:
      name: "UV Index"
    light:
      name: "Light"

Configuration variables:¶

uv_index (Optional): UV index (UVI). All options from Sensor.
uv (Optional): Sensor counts for the UV sensor (#). All options from Sensor.
light (Optional): Lux of ambient light (lx). All options from Sensor.
ambient_light (Optional): Sensor counts for the Ambient light sensor (#). All options from Sensor.
gain (Optional, string): Adjusts the sensitivity of the sensor. A larger value means higher sensitivity. See table below for details. Default is "X3".
resolution (Optional, int): ADC resolution. Higher resolutions require longer sensor integration times. See table below for details. Default is 18.
window_correction_factor (Optional, float): Window correction factor. Use larger values when using under tinted windows. Default is 1.0, must be >= 1.0.
address (Optional, int): Manually specify the I²C address of the sensor. Default is 0x53.
update_interval (Optional, Time): The interval to check the sensor. Defaults to 60s. It is recommended that the update interval is at least 1 second since updates can take up to 800ms when using a high resolution value.

\[\text{lux} = \frac{0.6 \times \text{als}}{\text{gain} \times \text{int}} \times \text{wfac}\]

\[\text{UVI} = \frac{\text{uv}}{\text{sensitivity}} \times \text{wfac}\]

where:

als and uv are the sensor values
gain is the amount of gain, see the table below for details
int is the integration time in 100s of ms and is tied to the resolution, see the table below for details
sensitivity has the value 2300 and is the sensor’s count per UVI
wfac is the window correction factor