A combined ambient light magnitude and light source direction sensor controls the headlamps and cabin climate of a vehicle. The combined unit employs a photodiode having a predetermined spectral response and a diffuser which also has a predetermined spectral response, the spectral responses being combined...http://www.google.co.uk/patents/US5416318?utm_source=gb-gplus-sharePatent US5416318 - Combined headlamp and climate control sensor having a light diffuser and a light modulator
