MCU for lighting sensor.

The MSP430 series microcontrollers are capable of performing duties of a lighting

sensor. The MSP430F2012 and MSP430F2013 have built in analog to digital

converters which could be connected to a photo diode for the purpose of measuring

light intensity.

Other members of the series may be less expensive, and some of those might lack

an analog to digital converter, but could still interface digitally to a digital sensor or

they could read the quantized value of an analog input relative to a threshold.

Cost, interface features, and other considerations will dictate which device you

should use.  If you were more specific about your needs perhaps more specific

product recommendations could be given.