I need help with a car anti-theft device circuit schematic

[BoatingJoe]

I'm working on a school project and I have to find and/or make a circuit schematic to a car anti-theft system that will disconnect the car battery shortly after the car alarm goes off. I am new to the electronic engineering field but I can differentiate a few different components on a schematic diagram but I would say that I can navigate simple schematic diagrams with some ease.

 

[berkeman]

I'm working on a school project and I have to find and/or make a circuit schematic to a car anti-theft system that will disconnect the car battery shortly after the car alarm goes off. I am new to the electronic engineering field but I can differentiate a few different components on a schematic diagram but I would say that I can navigate simple schematic diagrams with some ease.

Welcome to PF!

But if your circuit is powered by the battery, won't it stop working when it cuts off its own power? And the battery circuit is a very high-current circuit, so it will take a monster relay to do the disconnect. Can you post the full text of the project assignment? Thanks.

 

[Averagesupernova]

I feel safe throwing out some hints. Yes the battery is a very high current source but there are ways to disable a vehicle without disconnecting the complete battery. The question is: Is there a specific requirement?

 

[BoatingJoe]

I feel safe throwing out some hints. Yes the battery is a very high current source but there are ways to disable a vehicle without disconnecting the complete battery. The question is: Is there a specific requirement?

Well we don't have a specific requirement since we have to come up with a product that has something to do with security and if we make something that already exists, we have to improve it in some way. My group decided with preventing the car from being hot-wired and the whole car being stolen and we want to disable the power completely.

I have not made a circuit schematic with anything but a DC power source, resistor, and LED light. So I have no clue how to do anything complex.

 

[BoatingJoe]

Welcome to PF!

But if your circuit is powered by the battery, won't it stop working when it cuts off its own power? And the battery circuit is a very high-current circuit, so it will take a monster relay to do the disconnect. Can you post the full text of the project assignment? Thanks.

"won't it stop working when it cuts off its own power?" Yeah, that's the idea. After a certain amount of time of the car alarm going off, I don't know how but maybe some kind of IC will trip some kind of switch— like a circuit breaker— that would have to be manually reset after the device system cuts the power.

"Can you post the full text of the project assignment?" Since I'm still in school, so the assignment is for the class to design something that has to do with security and my group decided to prevent the car itself from being stolen. We thought of a suicide circuit that can just disable the car battery so the car cannot be hot-wired and started.

 

[berkeman]

so the assignment is for the class to design something that has to do with security and my group decided to prevent the car itself from being stolen. We thought of a suicide circuit that can just disable the car battery so the car cannot be hot-wired and started.

Well, think this through a bit farther (you may have already done so)... Somehow the car owner needs to be able to reset the system so they can still drive their car after the failed theft attempt. But what will prevent the thief from using the same reset mechanism? If it's just a mechanical reset switch under the hood, the thief will be able to pop the hood and reset it just like the car owner wood.

 

[TonyStewart]

Back in the 80's our Manitoba provincial gov't owned Vehicle Insurance company (Autopac) had the best service and non-profit rates and gave rebates year-end, if they made a profit. I wish we had this in Ontario.

Then due to rising car thefts but modern vehicle anti-theft RFID's but before modern theft tools, they gave a free offer of a wireless Interrupter that would disable the front hood unlock and ignition supply. Older vehicles were eligible.

Now they have cheaper version that just cuts off the fuel pump. So it must be installed where it is hard to guess.

https://www.amazon.ca/dp/B091TPXY3D/