This sensor has a calibrated light sensing algorithm that can calculate UV Index. It doesn't contain an actual UV sensing element, instead it approximates it based on visible & IR light from the sun.
It is a digital sensor that works over I2C and you can safely use it with 3 or 5V microcontrollers. You can connect up an IR LED to the LED pin and use the basic proximity sensor capability that is in the SI1145 as well.
Features: