Door Security Alarm Circuit using Magnetic Reed Switch

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Introduction

In the modern era where everything relies on technology, using a simple lock key for security is insanely backward. Even the intruders of today’s world use technology. Therefore, we must have to use some kind of lock circuits that can secure homes, offices, banks, lockers, and places that needs security. And, not just secure it but also enable the user to get the update or news through the alarm when anyone passes by. Hence magnetic reed switch can be used for this purpose. So, in this article, we are going to make the Door Security Alarm Circuit using Magnetic Reed Switch.

The magnetic reed switch is the electrical switch operated by the magnetic field, that controls the flow of electrical current in the circuit. The reed switch has two types. For the first type, when there is an applied magnetic field, the contacts become part of this magnetic circuit. Hence the contacts make opposite poles and attract each other. Thus, called ‘Normally open contact’. The second type of switch is closed in normal conditions and gets opened while the applied magnetic field is. Therefore, called ‘Normally Closed Contact’.

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2$ PCB Prototype

Hardware Required

S.no	Component	Value	Qty
1.	PCB Board	–	1
2.	Reed Switch	–	1
3.	Resistor	680ohms, 10K	1, 1
4.	Capacitor	22uf	1
5.	LED	–	1
6.	Transistor	BC547	2
7.	Power Supply	9V	1

Circuits Diagram

Working Explanation

Build the Door Security Alarm Circuit using Magnetic Reed Switch according to the above diagram. For a video tutorial, click the below link.

When there is someone around the reed switch device, the magnetic force gets generated parallel to the sensor. This magnetic force builds the whole magnetic circuit and gives opposite polarities to the contacts of a reed switch. Hence they attract each other, and the current starts to flow in the circuit. As a result, the buzzer beeps, and LED glows.