A fire alarm system is a device that makes a loud sound to warn people when there is a fire. In this project we have designed a simple and inexpensive fire alarm circuit by using a transistor BC547 and an IR receiver sensor. This fire circuit alerts through a buzzer sound whenever any kind of fire is detected in the air or an environment. It can detect any kind of fire, such as radiation, heat, etc. Depending on the type, a sensor that matches an application is selected. In the market, most of the circuits are expensive and difficult to buy. An infrared light sensor, on the contrary, is sensitive and very easy to use.
Block Diagram of Fire alarm circuit
Components Required
The list of necessary component items required for the fire alarm circuit:
- Infrared IR LED
- LED for indication of any color
- Transistor c945 or any NPN
- Buzzer
- 3.7V Battery
- Breadboard if needed
- some pieces of wires for connections
Fire alarm circuit diagram
The circuit diagram of this device is given below.
Fire Alarm circuit Diagram for 9v
You can operate this circuit by using a 9 to 12 V battery with a slight change in the circuit. We have to use only 1 resistor with the LED because the LED will burn without a resistor if we use more than 6 volts.
Working Explanation
The working of a fire alarm circuit is very easy. An IR sensor is an electronic device that is used to detect infrared radiation falling on it. The heart of the fire alarm circuit is an infrared receiver and infrared transmitter. In default operating conditions when infrared light is shining from the infrared transmitter, it will have low impedance. So the voltage at the base will be very low and the transistor will remain in off position. In case a fire is detected, the infrared beam will not be able to pass to a receiver. The resistance of the receiver rises, and the voltage at the base will become positive, and the transistor turns on. The buzzer and LED connected with the transistor will also be on.
Application
Some important applications of Fire Alert circuit are as follows:
- Industries
- Hospitals
- Banks
- Homes
- Security departments
Advantages
Some advantages of fire alarm system are given below
- Early Fire Detection
- Decreased Risk of Fire Damage
- Discounts on Insurance
- Home Fire & Life Safety
Classes of Fire Alarm
There are a total of seven classes of fire alarm systems. These classes don’t show how to wire anything; these classes show what happens when things go wrong.
- Class A
- Class B
- Class C
- Class D
- Class E
- Class N
- Class X
For full detail of these classes, please click