TWH9250 radar detection module based on the type of alarm (1)

With the substance of constantly enrich and people's standard of living is increasing rapidly, and people's safety awareness continues to increase, many families and units are installed anti-theft doors and Windows, doors and Windows to ensure the security of personal and property safety has played a positive role.

However, like the Treasury, warehouse, laboratory of such important places, relying on simple anti-theft doors and Windows is not enough, you must also install burglar alarm device. Common alarm with infra-red alarm, touch alarm, burglar alarm and magnetic induction alarm, etc.; these common weaknesses burglar alarm is monitoring scope memory in dead ends, as criminals committing provides an opportunity. In order to address the dead angle monitor not problems, using TWH9250 radar detection module [1], designed a new type of Omni-directional microwave alarm no dead ends.

I. composition of burglar alarm

Consider the alarm when the probe to the warning should have a sound and light alarm function, but also on the scene for camera control, so that the design of the circuit structure is used to launch on the subject of cyclic microwave antenna, you should include radar detection module, alarm IC, integrated audio power amplifier circuit, infrared camera control circuit and DC power circuit five parts, the composition of the block diagram shown in Figure 1.

Second, the burglar alarm circuit design

1. detection module TWH9250 introduction

TWH9250 is an innovative radar detection module, the module has the following characteristics:

(1) microwave tube scan launch detection distance;

(2) omni-directional detection; no dead ends

(3) power consumption may be small, battery-powered;

(4) the internal circuit adopts open-collector output terminal with flexible and can be direct drive small relay;

(5) with light kongduan and sensitivity adjustment, meet a variety of occasions;

(6) the external circuit is simple, as long as connected to the ring antenna and Terminal executing agencies, power can work.

TWH9250 module form, pin arrangement and internal circuit function block diagram shown in Figure 2.

Loop antenna transmitting microwave signal form a solid network of microwave warning, when someone in net when walking, volunteers move reflected microwave signals, in which case the microwave generator "circuit will produce as objects move in weak low frequency signal.

The signal level zoom-70dB left, into the Windows comparison circuit voltage and pulse width compared to dual differential circuit. When the confirmation signal voltage amplitude and width are set, the latch circuit to trigger, the trigger signal controlled door to count control circuit for output delay, the delay time is set to 10s and, finally, the last stage power tube collector output. To improve the stability of microwave circuit, circuit of precision, the section of the circuit from 4V and 7V regulator system separate from the power supply. The circuit in the initial power on at the time by the 40s pre stability in order to enter the detection alert, later as long as they do not power off, the circuit at any time at detection status. TWH9250 module working voltage of 12 V. The lead foot function as shown in table 1.

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