Introduction
In this new era where we cannot rely on the old traditional security systems, many modern security devices and systems are coming. And, the laser tripwire alarm circuit is surely one of the best. The circuit can detect the movement of a person at any sensitive place. Hence can be very useful in places like banks, museums, offices, and industries, and even great for homes. One thing which makes this circuit more promising is that it uses few affordable components. Though laser is a major part of this circuit, we also cannot disavow the presence of a light-dependent resistor (LDR). So in this tutorial, we are going to explore How to Make a Laser Tripwire Alarm Circuit.
But before making the circuit, one needs to understand the LDR. LDR is the electronic component in which resistance get decreased as the intensity of light increases. it means that until the light falls on the LDR; the circuit doesn’t work due to increased resistance.
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Hardware Components
You will need the following parts to build this project:
| S.no | Component | Value | Qty |
|---|---|---|---|
| 1 | Laser diode/pointer | 5V, 650nm, 5mW | 1 |
| 2 | Timer IC | NE555 Timer | 1 |
| 3 | Laser Security Alarm PCB | JLCPCB | 1 |
| 4 | LDR | 5mm | 1 |
| 5 | Buzzer | 5V | 1 |
| 6 | Latching Switch | SPDT | 1 |
| 7 | Resistor | 220 Ohm | 2 |
| 8 | Soldering Iron | 45W – 65W | 1 |
| 9 | Soldering Wire with flux | – | 1 |
| 10 | DC Battery | 9V | 1 |
| 11 | Heat Shrink Tubing | – | 0.5ft |
| 12 | Jumper wires | – | As per need |
Circuit Diagram
Working Explanation
To make this Laser Tripwire Alarm Circuit, connect the circuit according to the above-given diagram and give the supply. Now the laser light is constantly falling on the LDR and there is nothing in between. In this normal condition, the resistance of the LDR is higher and no current flows through the circuit. When someone comes between the laser and LDR then because of the presence of the shadow of that person, the LDR observes the darkness. Now, the resistance of LDR gets decreased, current flows through the circuit, and the buzzer beeps.
Applications
- It can be used for security purposes for banks, museums, and military areas.
- Also, can be utilized in home and industrial automation systems.
