Light/Dark Detector

Schematic

Parts

Part Total Qty. Description Substitutions R1 1 100K Pot Q1 1 2N3904 NPN Transistor 2N2222 Q2 1 NPN Phototransistor RELAY 1 9V Relay MISC 1 Board, Wire, 9V Battery Snap (if battery used), Knob For R1

Notes

1. R1 Adjusts sensitivity