Burglar alarm based on human body infrared induction module

[0012] The present invention will be further described below in conjunction with the drawings.

[0013] Such as figure 1 As shown, the anti-theft alarm based on the human body infrared sensor module of the present invention uses a 12V battery GB for power supply. The negative pole of the battery GB is grounded, and the positive pole is connected in series with the switch S to provide 12V power to the subsequent circuit. The subsequent circuit includes Human body infrared induction circuit and sound and light warning circuit.

[0014] The human body infrared sensing circuit is constructed by infrared sensing module HC-SR501 and time base circuit NE555 chip, 12V power supply is connected to pin 1 of three-terminal regulator 7805, pin 3 of three-terminal regulator 7805 is grounded, and pin 2 is connected to infrared sensor Pin 1 of the module HC-SR501; Pin 3 of the infrared sensor module HC-SR501 is grounded, and pin 2 is connected to the base of the transistor Q1; the emitter of the transistor Q1 is grounded, and the collector is connected to one end of the resistor R1 and pin 2 of the NE555 chip. The other end of R1 is connected to a 12V power supply; the 12V power supply is connected to one end of resistor R2, pins 4 and 8 of the NE555 chip, the other end of resistor R2 is connected to pins 6 and 7 of the NE555 chip and the positive electrode of capacitor C1, and the negative electrode of capacitor C1 is grounded. Pin 1 of the NE555 chip is grounded, pin 5 is connected to the capacitor C2 in series and grounded, and pin 3 is output to the sound and light warning circuit.

[0015] The sound and light warning circuit is constructed with Y976 alarm integrated circuit. The 3 pins of the human body infrared sensor circuit NE555 chip are connected to the resistor R3 in series, followed by the 5 and 8 pins of the Y976 alarm integrated circuit and the positive electrode of capacitor C3. The negative electrode of capacitor C3 is grounded, Y976 A resistor R4 is connected in series between pins 6 and 7 of the alarm integrated circuit, pin 4 is grounded, pin 1 is connected to one end of the resistor R5 and the anode of the capacitor C4, the other end of the resistor R5 is connected to the anode of the LED D1 and the cathode of the LED D1 Ground, the negative pole of the capacitor C4 is connected to one end of the speaker BL, and the other end of the speaker BL is grounded.

[0016] When the anti-theft alarm of the present invention is working, the three-terminal voltage regulator 7805 provides 5V power to the infrared sensor module HC-SR501, and the infrared sensor module HC-SR501 works normally. When the infrared sensor module HC-SR501 does not detect a thief entering the monitoring When the area is active, its pin 2 outputs low level, the transistor Q1 is off, the pin 2 of the NE555 chip is high level, the monostable flip-flop constructed by the NE555 chip is in a stable state, and the pin 3 of the NE555 chip outputs low level , The sound and light warning circuit does not work.

[0017] When the infrared sensor module HC-SR501 detects that a thief enters the monitoring area, its pin 2 outputs high level, the transistor Q1 is turned on, pin 2 of the NE555 chip becomes low, and the monostable flip-flop turns to a temporary In steady state, pin 3 of the NE555 chip outputs a high level. This high level is divided by the resistor R3 and then loaded onto the Y976 alarm integrated circuit. The Y976 alarm integrated circuit is energized to work, and the light emitting diode D1 and the speaker BL emit light and sound respectively Warning, proactively deter thieves in advance.