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

Voltage Controlled Switch with 555
Latching Continuity Checker
Oscillator Design Guide Structure
15dB UHF Antenna Preamp Circuit
Motorola TPN1154 and TPN1136 Desktop Power Supplies
Xbee doorbell project
Wideband RF Amplifier
Circuit of graphic equalizer of 7 bands using it integrated la3607 of Sanyo
ADA4858-3 used as a PIN diode driver circuit



Top