Microwave language anti-theft alarm

Relevant key device information applied in this article: RD627 μA741 LQ46-88D 78M12 microwave language anti-theft alarm is suitable for use in homes, shops, warehouses, orchards and other places. As long as someone enters the warning range of the alarm, it will sound "Catch the thief". In order to prevent the alarm from being vandalized, the circuit is equipped with disconnection alarm and automatic AC/DC power conversion functions. The circuit principle is shown in the figure. The alarm consists of two parts: the probe and the host. The probe consists of microwave sensing module RD627 and operational amplifier A1. The output signal of RD627 is amplified by operational amplifier A1 and connected to the host through a two-core shielded cable. The comparator composed of operational amplifiers A2 and A3 in the host circuit identifies the signal sent by the probe; LQ46-88D is a special speaker for voice alarm. It only has a power pin on the outside. After the power is turned on, it can send out "Catch the thief" the sound of.