This is a library for the Si1145 UV/IR/Visible Light Sensor Designed specifically to work with the Si1145 sensor in the adafruit shop ----> https://www.adafruit.com/products/1777 These sensors use I2C to communicate, 2 pins are required to interface Adafruit invests time and resources providing this open source code, please support Adafruit and open-source hardware by purchasing products from Adafruit! Check out the links above for our tutorials and wiring diagrams Written by Limor Fried/Ladyada for Adafruit Industries. BSD license, all text above must be included in any redistribution To download. click the DOWNLOADS button in the top right corner, rename the uncompressed folder Adafruit_SI1145. Check that the Adafruit_SI1145 folder contains Adafruit_SI1145.cpp and Adafruit_SI1145.h Place the Adafruit_SI1145 library folder your arduinosketchfolder/libraries/ folder. You may need to create the libraries subfolder if its your first library. Restart the IDE.