Daylight Brightness Switch

[Munroast]

Shop Window - gets the sun in the afternoons, when the sun is shinning no need to have lights on.

Would like to have some sort of sensor that would automatically turn lights on and off. The threshold would need to be bright sunshine (not daylight)

Window lights comprise of 3 x 150w Metal Halides

 

[Taylortwocities]

Fit something like this
http://www.tlc-direct.co.uk/Products/DNTWSW.html

its advertised as a dusk to dawn switch but its adjuststable so you'll be able to set it for the lights to come on at whatever light levcel you want.

See teh spec.
FYI A lighted parking lot at night is about 10 LUX (average)