Microprocessor-based home security system

Posted on Feb 7, 2014

A microprocessor based project Microprocessor-Based Home Security System . This advance security system not only let you know but also alert police immediately. In the project 8085 microprocessor based home security system we can control siren, telephone (via cradle and redial switches) and cassette player (alert message is recorded already) The mechanism of the project Microprocessor

Microprocessor-based home security system
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Based-Home Security System  is very simple. As this project is IR based, the IR ray from transmitter is focused in the base of phototransistor of receiver fitted in opposite to each other. The property of phototransistor is that whenever the IR ray focused on its base is obstructed, the microprocessor as per program burnt in EPROM which further control siren, telephone and cassette player. Hardware: The complete circuit-Diagram of Microprocessor Based Home Security System  is shown in figure 1. The transmitter section is designed and fabricate around timer IC NE555 wired as astable multivibrator followed by transistor T1 and IR LED. The oscillated frequency of transmitter section is decided by resistor R1 and R2, preset VR1 with capacitor C1. The output from pin 3 of IC1 is given to base of transistor T1 through resistor R3 for amplification as per required and given to IR LED. The modulated IR signal is transmitted by IR LED1. The IR transmitted signal is focused on the base of photo transistor. The output from photo transistor is given to transistor T3 followed by op-amp (IC2) for amplification. The amplified signal from IC3 is given to input pin 3 of Phase-Locked-Loop (PLL) IC LM567 (IC3) through capacitor C4. The normal use of PLL IC (IC3) is frequency decoder so is here in order to drive the load. The tuning frequency is determined by variable resistor VR2 and current controlled oscillator by resistor R12. The tuning...

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