42/KIT. IR Security system

We live in a world wherein certain times, everyone lives in their home, going through their lives, until burglaries are occurring at home, and so the owner of the house becomes the victim. To make your home protected, you will need a security system, which can detect any intruder breaking in the house, and alert you that an intruder broken into your house.

<Entire system>

This project can alert if an intruder either walks into the restricted area or if he/she touches the item, managing to steal the item. This project is based on the Velleman kit: MK120 IR light barrier. The modification created for this kit is that instead of a buzzer, it uses a 12-volt relay (paired with a diode) to act as a trigger switch.

<Insides>

When the LED emits infrared light from the transmitting circuit to the receiver, the receiver will remain inactive, but once the IR beam is blocked, the receiver will start to activate the alarm, until it senses the IR light again.

Of course, having it trigger on and off only when the IR beam is detected, is not enough for a security system. It needs to have a delay function-When the IR beam is blocked, it activates the circuit, but even when the IR beam is detected again, it still triggers under a certain amount of time before it deactivates. This is when a second circuit is needed, for the modified receiver circuit. A simple delay circuit will consist of a transistor, a resistor, a capacitor, and another 12-volt relay (Paired up with a diode).

<Planned>

This will provide a delay time once the receiver circuit is activated, and will deactivate by a certain time. You can change the values of the resistor and capacitor, to change the amount of time needed to keep the delay circuit activated.

The relay on the delay circuit has an internal switch and can be connected to your alerting source: from a loud buzzer, a recorder, or anything that has a switch to keep it active. Everything for the receiver is housed inside a plastic box, to make it protected.

It's a simple project, but once it is implanted in real-time, you can effectively protect your home, and your belongings, from intruders.

<Test>

<Time Delay Circuit, used as a module in this project>