DIY Pyroelectric Infrared Sensor Kits Anti-Theft Circuit Electronic Soldering Practice Board

Description:Power support: AC 6-12VSize: 82 x 44mmTexture of material: Two-sided 1.6mm FR-4 boardLong life Low ESRFunction:Pyroelectric infrared sensor security circuit consists of pyroelectric infrared sensor PIR, integrated operational amplifier LM358, voltage comparator LM393, 110 alarm circuit and boot delay circuit, etc.. The circuit can be used as home security. When the family leaves room, the switch K1 is closed, the circuit starts to work. As long as someone enters room after a period of time, it will sound alarm.1. The circuit is energized, the pyroelectric infrared signal of infrared sensor PIR to detect the front radiation of human body, from the signal PIR 2 feet output weak, after amplification transistor VT1, through the C2 input to the op amp IC2A 3 foot high gain low noise amplifier, and then by IC2A the 1 foot output signal.2. IC2B in the circuit as a voltage comparator, its 5 pin voltage reference is provided by R10, VD1, IC2A when the 1 foot output signal to the IC2B 6 feet, 5 and 6 foot input voltage is compared, if at this time the 6 foot voltage ratio 5 feet high, 7 feet of IC2B from high level to low level. The C6 through the VD2 discharge, the IC3 2 feet into low level, if the voltage reference voltage of 2 feet than 3 feet of a resistance R14, partial pressure of R15 with low IC3, the 1 foot into a high VT2 transistor conduction music chip IC4 the 2 foot voltage, output audio signal after amplification transistor VT4, buzzer driver BELL issued 110 al