Eight-way wireless anti-theft alarm system

Relevant key device information applied in this article: HL911L TWH8778 KD9562 FDD5 JDD5 (a) Shown is the alarm monitoring and transmitting extension. KD9562 consists of eight alarm monitoring and transmitting extensions through eight trigger terminals. The pyroelectric infrared detection module HL911L forms an anti-theft monitoring circuit. When a theft occurs, the ① pin of HL911L outputs a high level to connect the internal circuit of the electronic switch circuit TWH8778. The high level output from pin ③ of TWH8778 enables the relay. K is energized and closed, the contact switch KS connects the transmitting component FDD5 to the working power supply, and FDD5 starts to work. The 5V power output from pin ② of TWH8778 enables KD9562 to obtain working power. The analog audio signal output by its output terminal is input to FDD5 through pin ③, and is transmitted outward after modulating the carrier frequency inside FDD5. KD9562 can emit eight different analog sounds through eight trigger terminals, representing eight different monitoring points. (b) shows the alarm receiving host of the system. When JDD5 receives the alarm signal sent by the alarm extension, through internal demodulation processing, the output terminal outputs an analog audio signal, and the alarm sound is emitted through the speaker.