First Many thanks for Claws , He created a library for BH1750 , You can check it Out .
I prepared a library for it , Tried to solve some issue such like :
1) multi device connecting , You can connect 2 devices of BH1750 WIth different addresses , Depend on ADDR Pin status .
If ADDR = LOW , The address will be 0x23
If ADDR = HIGH, The address will be 0x5C
2)Power down mode , you can put your sensor in power save mode so it's consume 0.01uA .
You can downLoad the library from Github , Unzip the attachment and put it in Libraries folder in arduino Path , then restart the arduino IDE .
You can Open the sketch comes with this library .
First program : Read the Lux value via serial Port .