SI1145 - UV Index / Infrared / Visible Light sensor
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SI1145 - UV Index / Infrared / Visible Light sensor

  • UV Index
  • Visible Light
  • Infrared (IR)
  • Digital sensor
  • I2C Interface
  • 3.3v & 5V compatible
€12.52 (tax incl.) €10.35 (tax excl.)
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Digital sensor : UV index / infrared / visible light

Do you remember those holidays at the sea. When our parent want us to add a new layer of sunscreen on the skin. It is important to take care about the ultraviolet light but when do we have enough (or not enough) sunscreen.

So, here a sensor that may help you find the right response to "A'm I proprely accordingly?"

By connecting this calibrated UV Index sensor to an Arduino, you can read the UV Index (eg: 4.5) and determine if you had enough of the sunscreen on your skin".

The SI1145 is a sensor from SiLabs including a calibrated light sensing algorithm used to calculate UV Index. This sensor does not contain an UV sensing element but  approximates the UV from visible and IR light.
The calculated data of this sensor have been compared to the index reported at the news. The sensor prooved that it was very accurate!
Le SI1145 is an I2C digital sensor, so you can use it with any microcontroler. The sensor has 2 elements : one for the vivible light and another for the infrared light sensing. This means that you can measure any kind of light.
Adafruit did wrote the library to display the index value (the "counts") but will not provide the exact Lux value for the lights. If you need precision Lux measurement then we suggest the to take a look for TSL2561.
You can also connect up an IR LED to the LED pin and use the sensor as a basic proximity sensor (also included in the SI1145).

The sensor is placed on a nice breakout board with level shifting and power regulator so you can use this board with 3 or 5V microcontrollers.

Technical details

  • Size: 20mm x 18mm x 2mm
  • Weight: 1.4g
  • IR Sensor Spectrum: Wavelength from 550nm to 1000nm (centered on 800nm)
  • Visible Light Sensor Spectrum: Wavelength from 400nm to 800nm (centered on 530nm)
  • Power Supply: 3 to 5VDC
  • I2C interface: defaut address 0x60 (7-bit)
  • Operating Temperature: -40°C ~ 85°C
  • Datasheets, Fritzing objects, and EagleCAD PCB
    Available from the Adafruit tutorial   


Each order comes with one fully assembled and tested breakout board. You will also receive a small piece of header. You'll need to solder the header on the board to use it with a breadboard. It's fairly easy and should only takes a few minutes (even for a beginner).