The SI1145 is a calibrated UV sensing element that can calculate UV Index.
It’s a digital sensor that works over I2C so just about any microcontroller can use it.
The sensor also has visible and IR sensing elements so you can measure just about any kind of light – but only the UV sensor has a calibrated output so if you need precision Lux measurement check out the TSL2561. If you’re feeling really advanced, you can connect up an IR LED to the LED pin and use the basic proximity sensor capability as well.
