Vehicle Immobilizer Circuit Explained

If you own a car and still haven’t incorporated any security system in it or perhaps your old security system is out of order, you can quickly opt for a cheap yet effective security option for your car or any vehicle by installing the proposed circuit. It will cost you not more than a dollar.

Circuit Operation:

The circuit can be easily built over a small piece of vero-board by soldering all the components with reference to th shown circuit diagram.

After making the simple vehicle immobilizer circuit and housing it appropriately, the unit can be integrated to your vehicles ignition for the required immobilizing actions.

Let’s understand the circuit with the following points:

Referring to the above simple cheap vehicle immobilizer circuit, we can see that the whole circuit is fundamentally comprised of only a single passive component a high voltage capacitor (10 uF/400V).

As we all know capacitors have the property of grounding any signal that is made up of some kind of frequency, or rather a capacitor will always allow an AC to pass through it. This property is well exploited here to get the required security feature from the proposed circuit.

All vehicle system primarily utilize their ignition system for starting and for sustaining their engine movements. Thus the ignition system becomes the heart of the vehicles as far as their working is concerned.

The ignition system works by igniting a fuel mixture inside the ignition chamber through consistent high voltage arcing. This high voltage arcing is generated from the ignition coil.

Therefore, finally we know that it’s the high voltage arcing that needs to be inhibited to stop the vehicle or for making it completely immobilized. By introducing a high voltage capacitor across the main ignition high voltage source and ground, we can easily terminate the passage of the high voltage pulses to the spark plugs and completely disable the ignition process.

As shown in the figure this is simply done by connecting the capacitor leads to the relevant points. However if you wanted to override the system you could easily do it by disconnecting the capacitor from the system, simply by activating a hidden switch.

This switch can be placed somewhere inside the bonnet or in some hidden place that would be known only to you. For the installation of the entire wiring, you can take the help of a professional cat electrician.

About the Author

I am an electronic engineer (dipIETE ), hobbyist, inventor, schematic/PCB designer, manufacturer. I am also the founder of the website: https://www.homemade-circuits.com/, where I love sharing my innovative circuit ideas and tutorials. If you have any circuit related query, you may interact through comments, I'll be most happy to help!