With the BH1750FVI can be measured the illuminance in lux at a point. Areas of application are, for example, photography, automatic switching of lamps for lighting at night or dusk and much more.

BH1750FVI illuminance sensor on a breakout board (GY-30)

Specifications:

• BH1750FVI from ROHM Semiconductor
  
• Measurement range: 0 – 65536 lux
• I²C interface
• Supply voltage: 3 – 5V
• Dimensions (GY-30): 33mm x 16mm

Further information on illuminance in Wikipedia, as well as examples of typical illuminance also there.

Project with the BH1750FVI:

• Measurement of illuminance with a BH1750FVI Breakout Board (GY-30) and an Arduino Uno

Components:

eBay:	BH1750FVI
Amazon:	BH1750FVI

Good?