r54

IR LASER LIGHT DETECTOR

Prom SI A

SI A

O +9Vdc

<y*o

9Vdc

9Vdc

i

i

0^0

S1B

C3

330nF —O ~9Vdc

The universal laser light detector. The output of the LM386 audio amplifier can be connected to a smali 8-Q speaker or ear-phone. TWo 9-V batteries provide power. Decrease R1 to lower sensitivity; increase R3 to increase gain of the op amp (avoid very high gain or the op amp might oscillate). Q1 is an infrared phototransistor.