Wireless transmitting and receiving intelligent monitoring alarm circuit module

RF cable can be customized for other specifications

Figure (a) mainly uses two CMOS type 555 (or a 556) IC1, IC2, which respectively output 1.5kHz and 35kHz waveforms, wherein the 35kHz carrier is modulated with a 1.5kHz square wave. In the figure, IC1 is connected to a multivibrator with an oscillation frequency of 1.5 kHz, which is determined by the charge and discharge time constants corresponding to R2, R3, D6 and C4. The duty cycle of the IC1 output square wave is 1:3 (160μs: 500μs). The oscillation frequency of IC2 in the figure is determined by the charge and discharge time constants corresponding to R4, R5, and C6, and the IC2 oscillator is controlled by the square wave output from IC1. In order to enhance the infrared power of the emission, the infrared emission tube can be connected and connected in parallel, and the effect of using the concentrating lens is better. This circuit uses CMOS type 555. If bipolar type 555 is used, its output current can reach 200mA. Then, when the monitoring distance is close, the LED can be directly connected to the output pin 3 of the 555 without adding a triode T-push.

Figure (b) is an infrared receiving circuit. The μPC1373 is an integrated device with high gain preamplifier and detection. The 3-pin LC loop has a tuning frequency of 35kHz (same as the carrier). IC3 (567) is a pure tone decoding integrated circuit with a phase-locked loop that stabilizes the frequency at 750 kHz by adjusting W and C.

The alarm circuit can be used for infrared monitoring warehouses, treasury and the like. When it is found that someone breaks into the forbidden zone, the infrared receiving circuit automatically activates the wireless transmitter, and transmits and remotely remotely receives the receiver alarm.