Nowadays security is the more important role in our day to day activities, in general, we protect our door using a hardware lock system.
Most of the time thieves can easily break or open your door lock and entering in your house when you are not present at your house or you are alone in your house.
At that time the door security alarm system is more useful and that can save your time and money.
They are small rechargeable battery-operated devices so no need for any active AC source connection.
What is the Door Security alarm system is?:
In this project door security alarm system, we will see when the door will open then the alarm will ring through the buzzer.
Magnet operated Reed switch connected to the circuit operating buzzer.
The switch placed on the corner of the frame of the work and magnet fixed on the going part of the door using adhesive.
We need the following tools and components for our project.
- Dotted PCB —– Amazon
- Buzzer———– Amazon
- Normally Open Magnetic switch– Amazon
- Battery cap
- 9v Battery —– Amazon
- Electronic capacitor 2uF 50v —- Amazon
- Resistors R1=1M ohm and R2 = 333 ohms —- Amazon
- Transistors (2) BC547 — Amazon
- LED 5mm—- Amazon
Door Security Alarm circuit Description:-
What is totem pole circuit?
The totem-pole output is also known as a push-pull output, its a type of electronic circuit. and usually realized as a complementary pair of transistors.
It’s connected in such a way that the emitter’s first transistor is connected to the base of the second transistor.
- In this circuit, there two totem pole transistor connections (Q1 & Q2).
- In Q2, the transistor keeps used to drive other transistors Q1.
- When the door closed, the circuit is in rest condition and the reed switch is close and when the door opens the circuit is in ON condition and the reed switch is open.
There are two types of reed switch :
- Normally open (NO)
- Normally close (NC)
In this project, we used a normally opened reed switch.
In normally open switch, the switch kept open as a normal condition. and when the magnet comes nearer to switch will be close.
Steps of Working:-
- Place the component on dotted PCB as per the circuit diagram of the door security alarm system.
- Make a hole in the plastic box for external connections, we use a plastic box for our door security alarm system.
- Connect reed switch to the circuit
- Connect buzzer and battery connected to the circuit and
- The circuit is ready.
As we see the introduction, this project is helpful in simply safety entry and also used as a doorbell.