Thanks Ron, I will think about that circuit.

 

Just a suggestion:

Purchase an infrared phototransistor. Attach to Multimeter and measure resistance. Turn the incandescent on and hold the phototransistor in the place it will sit once complete. Measure the resistance of the phototransistor. (Depending on the light source and position, it could be 100K+)

Place phottransistor as the base on an NPN transistor, place a potentiometer or a pot to ground the base (Or don't connect it to ground at all, I don't know how it will work out for you).

On the collector of the NPN place a resistor with the same resistance you just measured using the multimeter and phototransistor. This will calibrate the transistor to turn "On" when sufficient light strikes the phototransistor.

Attach the base of another transistor to the emitter on the previous. Complete circuit as you desire. If the second transistor wont turn "off" like you desire, play around the resistance values between the base and ground.

Current flow through this design will probably be abysmal, so don't be afraid to add more transistors to amplify as necessary.