At lower left, where 1 k ohm resistor is should be an electret microphone. To simulate, the switch, 1 uf capacitor, and 1 kHz generator is added. This allows for lamp to suddenly turn on when sound happens to give impression someone is inside. This can be powered from 5 volt to 12 volt battery.
Note when first powered on relay comes on during charging of 4.7 uf capacitor and should turn back off in a few seconds. Change timing by this capacitor using 4.7 uf through 47 uf values. To change microphone sensitivity, adjust upper left 5.6 k ohm resistor using trail and error to set response to sound at level you desire.
