Wireless Ir Security System

Posted on Jun 26, 2012

This system contains an IR transmitter, an IR receiver/RF transmitter, and an RF receiver/alert beeper. Two IR

Wireless Ir Security System
Click here to download the full size of the above Circuit.

LEDs in the transmitter transmit a pulsed beam of invisible infrared light to the receiver, which contains an IR phototransistor. The phototransistor detects and amplifies the pulse-modulated IR beam. If the receiver section senses that the IR beam is momentarily interrupted by an object blocking the beam"s path, it triggers the transmitter, which outputs a 49.890-MHz carrier that is amplitude-modulated by a 490-Hz tone. Upon receiving the 490-Hz amplitude-modulated carrier, the RF receiver/beeper unit sounds an alarm that alerts the user to the intrusion. The system is not limited to just one RF transmitter. A single RF receiver/beeper can be used to monitor any number of RF transmitters (or locations). However, the receiver/beeper unit cannot discriminate between different transmitter sites in multiple-transmitter systems.

Leave Comment

characters left:

New Circuits



Popular Circuits

Pic-Plot : a GPIB to RS-232 converter
ultrasonic mosquito repeller
studio synth circuit
Why are audio transformers required
overtone crystal oscillator
make these simple cheap home burglar
IR Remote Control Receiver
2X15 Watt stereo amplifier using TDA4935
Digital frequency counter
Sawtooth generator circuit a
Having a cold junction compensation Remote Isolated Thermocouple transmitter circuit diagram ISO102 XTR101
Temperature compensation of the symmetrical power supply 7812 F007C