Introduction
Nowadays safety is a major concern around the World. Many people employ guards for this purpose but many times these guards also get hit by intruders. The IR Based Security Alarm is a safety purpose circuit that gives a warning or signal alert when an intruder or invaders try to invade a home, museum, office, bank, or any other place. It thwarts the robbery and heist. So we have decided that in this tutorial, we will make this effective circuit known as an “IR Based Security Alarm using 555 Timer”
Hardware Required
| S.no | Component | Value | Qty |
|---|---|---|---|
| 1. | Photodiode | – | 1 |
| 2. | IC | LM555 Timer | 1 |
| 3. | NPN Transistor | BC547 | 1 |
| 4. | Speaker | 8Ω | 4 |
| 5. | Potentiometer | 10KΩ | 1 |
| 6. | LED | – | 1 |
| 7. | Resistor | 220Ω, 10KΩ, 1KΩ, 150KΩ | 1, 1, 1, 1 |
| 8. | Ceramic Capacitor | 0.1μF , 0.01μF | 1, 2 |
| 9. | Battery | 9V | 1 |
| 10. | IR LED | – | 1 |
Circuit Diagram
Working Explanation
In this IR Based Security Alarm using 555 Timer, the IC is configured as an astable multivibrator. The 9V battery supply is given at the Vcc pin 8 which is the Reset pin which is further connected with the collector pin of the transistor. The transistor is working as a switch. So, if the Infrared rays are received by the photodiode, the transistor connects the Reset pin to the ground. And, if IR rays are blocked, the transistor connects the reset pin to the positive supply. The output frequency of the circuit depends on the values of the timing capacitor C2, resistor R4, and potentiometer. Thus, you can observe the different levels of sounds by adjusting the potentiometer.
Application and Uses
- The circuit is mainly used for security purposes and to warn and alert others.
