This document describes an automatic fire alarm circuit using an IR LED and buzzer. The key components are an IR LED, which transmits infrared radiation, a buzzer to sound the alarm, and a 9V battery. When the IR path is obstructed, such as by smoke in a fire, the buzzer will sound to alert of the potential fire. The circuit works by having the IR LED on one side of a door frame and an IR sensor on the other - under normal conditions the sensor receives the IR radiation, but if the path is blocked the buzzer will activate the alarm.

1. AAUTOMATIC FIRE ALARM
using IR LED andusing IR LED and
BUZZERBUZZER

2. Introduction
Components
Discussion about key components
Circuit diagram
Working procedure
Discussion
Conclusion
Contents

3. 1.INFRARED LED (IR LED)
2.BUZZER
3.BATTERY(9V)
4. AND SOME CONNECTING WIRE

4. IR LED

5. IR LED

6. Circuit

8. Working procedure

9. Discussion
IR Sensor
 An IR sensor is a device which detects IR radiation
falling on it. There are numerous types of IR sensors
that are built and can be built depending on the
application. Proximity sensors (Used in Touch
Screen phones and Edge Avoiding Robots), contrast
sensors (Used in Line Following Robots) and
obstruction counters/sensors (Used for counting
goods and in Burglar Alarms) are some examples,
which use IR sensors.

10.  Buzzer Alarm
 This is also based on direct incidence of radiation on
the photodiode. Here, the IR LED is fitted on one side
of the door frame, and the photodiode on the other,
such that in normal condition, the IR radiation emitted
by the IR LED falls on the photodiode directly. As soon
as a person obstructs the IR path, the alarm goes off.
This alarm can be switched on at night, and switched
off in the day, during normal use of the door.

11. conclusion
An IR LED, also known as IR transmitter, is a special
purpose LED that transmits infrared rays in the range
of 760 nm wavelength. Such LEDs are usually made
of gallium arsenide or aluminium gallium arsenide.
They, along with IR receivers, are commonly used as
sensors.

12. and
Subscribe my Channel