POLICE SIREN SECURITY ALARM

GRACE JEAN D. FERNANDEZ

This is a security system which produces a wailing sound and alarms when there is an intruder or when there is someone interrupting the sensor.

DESCRIPTION

SIGNIFICANCE

SECURE PROPERTI

ES

SECURE HOUSES

ANTI- THEFT

FUNCTION DIAGRAMSWITCH LASER LDR

ASTABLE CIRCUIT is

OFF

ASTABLE CIRCUIT is

ON

BUZZER

CIRCUIT FLOW

Dark Detector Circuit

Astable Multivibrator Circuit

DARK DETECTOR CIRCUIT (1)

LDR is at MINIMUM VALUE

When it detects NO light

DARK DETECTOR CIRCUIT (2)

LDR is at MAXIMUM VALUE

When the LASER is directed

ASTABLE MULTIVIBRATOR CIRCUIT (STATE 1)

ON

OFF

470

47010K 10K

100uF

100uF

ASTABLE MULTIVIBRATOR CIRCUIT (STATE 2)

ON

OFF

470

470

10K 10K

100uF

100uF