DIY Security Laser Alarm System Prototype

Hello, I wanted to make a simple, yet effective „security“ laser trip-wire alarm system with components that are not „hard to find„. If you plan on making something like this be careful with all the tools, do not mess with electricity, and be careful.

WARNING :

The author of this instructable is not responsible for the way you use pieces of information, skills, techniques shown in this instructable, so once again be careful.

For easier explanation, I wanted to make this build „modular“ so, at the end of it, it would be easier to put together.

Because this build is „modular“ It is necessary to first make a relay photoresistor switch along with a tone regulator. In this build that part is probably the most time consuming.

Contactor

Speaker with amplifier

Switch (230 V AC)

Wires

Relay photoresistor switch

- Relay

- Photoresistor

- Transistor ( 2n2222)

- Resistors

Tone regulator

- NE555 Timer IC

- 0,047 uF capacitor

- Resistors

- Wires

Tools:

Soldering iron, solder, pliers, utility knife

There is not a lot of components in this circuit.

Probably the easiest way to make this is to put all of the required components on board, bend the components leads, and then using the soldering iron and some solder connect them accordingly.

This circuit is even simpler than the one before, so once again I recommend placing components on the board, bending component leads on the opposite side, and then solder them according to the schematic.

When the laser beam gets interrupted relay closes its contacts completing the circuit between 230V AC and contactors electromagnetic coil. When that circuit closes 4 switches also close (L1-T1; L2-T2; L3-T3)+ Auxiliary contacts 13-14.

In the first half of the video that lasts 17 seconds, it has shown the working principle of the relay photoresistor switch and "kill switch" and later the first alarm test. In the second video, I additionally added a 12v lightbulb, so there is not only a "beeping" siren sound but also visible light signalization.