sjtrny/ltr390

This is an esphome component for the LTR390 (ltr390) UV and ambient light sensor.

Installation

Copy the ltr390 directory into your ESPHome custom_components directory (creating it if it does not exist).

Dependencies

The I2C Bus must be set up in order for this component to work.

Minimal configuration

The following configuration shows the minimal set up to read temperature and humidity from the sensor.

i2c:

sensor:
  - platform: ltr390
    uv:
      name: "LTR390 UV"
    light:
      name: "LTR390 Light"

Available Sensors

light: calculated lux (lx)
als: raw light sensor count (#)
uvi: calculated UV Index (UVI)
uv: raw UV sensor count (#)

Optional Parameters

gain: Adjusts the sensitivity of the sensor. A larger value means higher sensitivity. See table below for details. Default is "X3".
resolution: ADC resolution. Higher resolutions require longer sensor integration times. See table below for details. Default is 18.
wfac: Window correction factor. Use larger values when using under tinted windows. Default is 1.0, must be >= 1.0.
address: The I2C address of the device. Default is 0x53.
update_interval: How frequently to poll the device. 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. Default is 60s.

Complete configuration

- platform: ltr390
  light:
    name: "LTR390 Light"
  als:
    name: "LTR390 ALS Count"
  uvi:
    name: "LTR390 UVI"
  uv:
    name: "LTR390 UV"
  gain: "X3"
  resolution: 18
  wfac: 1
  address: 0x53
  update_interval: 60s

Lux and UVI Formulas

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

Gain Parameter	gain
X1	1
X3	3
X6	6
X9	9
X18	18

Resolution (bits)	Integration Time (ms)	int
16	25	0.25
17	50	0.5
18	100	1
19	200	2
20	400	4

Datasheet

English datasheet

Hardware

The hardware is available from Adafruit https://www.adafruit.com/product/4831

sjtrny / ltr390