Infrared burglar alarm circuit

An infrared reflective burglar alarm utilizes infrared detection through reflective components, with a maximum detection range of up to 12 meters to trigger an alarm. When an intrusion is detected, a realistic barking sound is emitted to alert the owner of unauthorized entry. The circuit consists of a power circuit, an infrared probe circuit, a speech generator, and an audio amplifier output circuit. The power circuit is composed of a power transformer, a rectifier bridge, a filter capacitor, and a three-terminal regulator (7812). The infrared detection circuit includes an infrared reflection-type probe module, a resistor, and a Zener diode. The sound is generated by an integrated circuit, along with additional resistors and Zener diodes. The audio amplifier output circuit consists of an audio power amplifier integrated circuit, capacitors, and speakers. The system operates on AC 220V voltage, with a transformer and bridge rectifier converting it to a pulsating DC voltage. The infrared probe remains inactive until it detects a human body’s reflected infrared signal, triggering the alarm system.

The infrared reflective burglar alarm circuit is designed to provide an effective means of intrusion detection. The core components include a power supply circuit, which steps down and rectifies the AC voltage to a usable DC voltage. The transformer reduces the mains voltage (AC 220V) to a lower AC voltage, which is then rectified by a bridge rectifier to produce a pulsating DC voltage. This voltage is smoothed by a filter capacitor, ensuring stable operation for the subsequent circuitry.

The infrared detection system is centered around an infrared reflection-type probe module (IC1). This module emits infrared signals, which are reflected back by objects within its detection range, typically up to 12 meters. When a human body enters the detection zone, the infrared signal is reflected back to the module, which processes the signal and outputs a high-level signal. This signal triggers the speech generator circuit (IC2), which produces an audio output, simulating a barking sound to alert the owner.

The audio amplifier circuit (IC3) is responsible for amplifying the output from the speech generator. This circuit includes an audio power amplifier that drives a loudspeaker, producing a clear and loud alarm sound. The circuit design ensures that the alarm is sufficiently loud to be heard by the owner, even in noisy environments.

Overall, this infrared reflective burglar alarm system is an efficient solution for home security, utilizing simple yet effective electronic components to provide reliable intrusion detection and alerting mechanisms. The combination of infrared technology and audio output effectively deters unauthorized access, enhancing the safety of the premises.Infrared reflective burglar alarm, infrared detection using reflective components (maximum detection range of up to 12m) to trigger the alarm, when Pirates of the situation is detected, an alarm will sound realistic barking to alert the owner of "outsiders people invasion. " (1) infrared reflective circuit burglar alarm circuit from the power circuit, infrared probe guillotine circuit, speech generator and audio amplifier output circuit, as shown in FIG. Power circuit from the power transformer T, rectifier bridge pile, filter capacitor C4, G and three-terminal regulator set circuit composed of 7812.

Infrared detection circuit by the infrared reflection-type probe guillotine module IC1, resistor Ri, Zener diode VSI components. Sound by the sound generator integrated circuit IC2, resistor Rz, wind and Zener diode VS2 composition.

Audio amplifier output circuit consists of audio power amplifier integrated circuit IC3, capacitor c] ~ G, G and speakers: B components. (2) circuit works AC 220V voltage by T Buck, bridge rectifier, C6 filtered all the way to IC3 provide 15v DC pulsating voltage; another path roar regulator, IC1 to provide ten 12V operating voltage, + 12V voltage also after the monument island limiting pressure and VS2 regulator, to provide LC2 + 3V operating voltage.

In normal circumstances, IC1 output low. IC2 can trigger work, speakers BI. No sound. When a stranger enters IC1 vigilance probe guillotine area. Ki infrared signal emitted by the human body reflected back. IC1 receives the body reflected infrared signal and the signal to go to treatment, the trigger outputs a high level signal to the IC2 triggered by the work, the output of the audio signal. After this signal by the power amplifier IC7, drive BL loud barking, suggesting master "abnormal situation" took place.