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  • Security Alarm Circuit

  • Created: Mar 29, 2016

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This circuit is a simple security system that alarms when intruders are detected. The device should be strategically located to optimize its application. It specifically uses the 430453031836 of Wurth Electronics, which is a compact and highly sensitive switch. The device can be placed in front of the locker or mat that whenever the switch is pressed, it triggers the device and produce an audible sound. Its switch can be positioned in two different places that will produce two different sounds.

In the circuit, the two switches used can be placed in two different places. When switch S1 is pressed, diode D1 will conduct so as transistors T1 and T2, which is attached with the resistor. For the oscillation purpose, T1 and T2 get a positive feedback through capacitor C1. The presence of any intruder is indicated by the low tone frequency, which is generated when S1 is pressed and same thing happens with S2 that is being pressed, only that a high frequency tone will be produced. When either of the switches is pressed, the sound will continuously beeps until the supply is switched off.

This security alarm circuit can be used not only to warn users from intruders but it can also be used as a buzzer especially for disabled and elderly people. They can use it right away whenever they need some assistance.



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