I'm working on an Arduino project that, among other things, has an HC-05 bluetooth module. When completed, the truck will only start if my phone is within range and paired, or a key sequence is entered on a hidden button (valet mode). Also, the truck will only run for 1 minute without being paired or being in valet mode.

If you want to avoid using a micro controller, why not use a simple 555 timer circuit?

 

Look, this circuit is flawed for this main reason: If you are in the car and driving, and if you stop on a traffic light for example and someone points to you a gun and demand that you come out of the car and then the thieve drives way, you do not want the car to stop, neither you would touch anything to deactivate the vehicle and raise suspicion from the thieve. you simply get out of the car and the thieve drives away, then the car stops say a couple of minutes after and does not turn on anymore.
I designed and patented a circuit that does that way back in the early 70s.
The system worked like this: You get in the car, when when you sit on the driver's seat, a switch is activated that turns on a circuit, then the driver presses a hidden button that will enable the ignition to be turned on. then you drive normally. If the car is hijacked, then the guy will drive away and you are safe. What happens is that when you get out of your seat, the circuit is now reset (because of the switch under the seat), but keeps the ignition on. Because the hidden button has not being pressed, then a timer will start and when it times out, it kills the ignition and the car does not start anymore.
This also is true if the car is parked and someone gets in it and try to start it. It will not turn on, meaning the starter will turn the engine but there is no ignition to run the engine.

 

If the car is hijacked, then the guy will drive away and you are safe. What happens is that when you get out of your seat, the circuit is now reset (because of the switch under the seat), but keeps the ignition on. Because the hidden button has not being pressed, then a timer will start and when it times out, it kills the ignition and the car does not start anymore.

I would like the idea better if from under the seat an electro-mechanically activated hook, like a giant fishing hook, suddenly nailed the guy to the seat by the gonads.

Or, if that is too complicated maybe a spike that shoots through the seat impaling the hijacker.

Many moons ago, when I was a wee kid, back in the middle ages, my father had installed under the seat a hidden valve in the fuel line. If you did not know to turn it on there was enough gas in the carburetor and line to take you a couple blocks.

 

I now improved the circuit even more... see the details:

 

Out of desperation I kept on pondering about a "delayed, automatic car immobilizer" circuit, within my realm of electronics knowledge and finally succeed, as you might agree. Please help me to perfect it... for it might only require a couple of simple timers to replace the super cap?

I now improved the circuit even more... see the details: View attachment 94122

 

Is your car insurer happy about modifying the car's electrics? You don't want your insurance invalidated.

Once I have a good circuit, I build it and then ask the Nissan electrician to wire it up. That won't invalidate the car insurance.

 

Do you have a regular problem with getting car jacked?

Yes, here in St'go de Chile it's a daily "fun for drugged teens". Here we got 12-year pistol kids hijacking cars!
Soon, I'll be living in tropical Australia and (sadly) there too, drugged criminals hijack cars. - Lucky you, that you that in your living space drug problems of this sort still don't exist! - Maybe I should move to your place, instead?
The thing is, I don't want to argue and struggle with drug addicted monsters and just peacefully hand over the car keys...and let the thief know ...that the car got mechanical problems (!!) Inside the car, I screwed onto the chassis a locked box in which I hide the car's documents and spare keys...
That's the idea! Got it?

 

Lucky you, that you that in your living space drug problems of this sort still don't exist! - Maybe I should move to your place, instead?

We have winter that tries to kill us for 6 months a year and Mosquitos that try it for the other 6.

As for drugged up fools that steal vehicles they tend to disappear without many questions being asked. (lots of wide open plowed fields make for great unmarked untraceable grave sites.)

 

I finally made it! - Alec-t's kick, started me experimenting ...until I finally found what I was after. Please check my result in case I should change something for safety reasons:, but it really works to my expectations. It's very small, consisting of two Mini Reed switches inside one winding and I (UHU) glued all electronic directly onto an automotive 30A relay. It fitted into a neon bulb housing. It also got a hidden emergency switch in case the car goes to technical check,repair or in case the circuit fails to work.

 

I do kinda feel like im cheating But on my "weekend/trackday car", the immobilizer consists of a hidden fuel pump switch (which looks like a fog light switch), once switched over you'll get about 2 mins idling or 20 seconds moving before the carbs float bowls empty of fuel and the car stalls.

Big advocate of the KISS principle

 

I do kinda feel like im cheating But on my "weekend/trackday car", the immobilizer consists of a hidden fuel pump switch (which looks like a fog light switch), once switched over you'll get about 2 mins idling or 20 seconds moving before the carbs float bowls empty of fuel and the car stalls. Big advocate of the KISS principle

Down here, drugged pistol kids confront drivers and such a situation makes one forget pressing hidden buttons and requires an automatic anti hijack system.

 

Down here, drugged pistol kids confront drivers and such a situation makes one forget pressing hidden buttons and requires an automatic anti hijack system.

You and your neighbors need to run over some"drugged pistol kids" with your cars regularly. Pepper spray them too. Oh yes, it does work.

 

You and your neighbors need to run over some"drugged pistol kids" with your cars regularly. Pepper spray them too. Oh yes, it does work.

I used to be a soldier... and all I know is that a pistol bullet is faster ...then a car runs over a shooter or get pepper sprayed.
You see, that's the problem I try to deflate with this car immobilizer, which offers me to get away safely and get the car back, too.

 

I think there is quite a bit more exaggeration and paranoia behind this than being truthfully divulged.

If drugged up gun wielding kids were stealing cars here for joy rides here there would be a good deal of dead drugged up kids with bullets in their heads at the local morgue.

 

..... try to deflate with this car immobilizer, which offers me to get away safely and get the car back, too.

Yes and I believe non confrontation is a very good way, but you also need community actions to stop something that has obviously really gotten out of hand.

 

How about some type of NFC tag you wear as a braclet. Your could get a raspberry pi tag reader module and program it to open the fuel pump relay or ignition coil relay or even ground the crank position sensor signal circuit after you leave the driver seat for 3000mS.

Rugger also sells an anti car jack devise.

 

Here in St'go de Chile these drug addicts steal everything you got on you... wallet, rings or any jewelry, cellphone, house keys etc. So, best is not to argue with sick gangsters and be prepared. My device offers me the best chance to get away unharmed, for I hand them the car and just tell them that the car is bad, having starting problems, which they too will confirm in about 2 Min.and hopefully walk away and the insurance does the rest.
Here the justice is bad, policemen get shot, taxi driver drive off with your suitcases or shopping, most gangsters have 40 criminal records and still on the streets! They lack jails. - Jeez, it's time for me to get away from this horrible place. Don't ever think of visiting "beautiful Santiago" for it's all the contrary of what the travel offices tell you! Chilean politicians shower themselves in big salaries and age pensioners live in terrible poverty.

 

I finally made it! ... it really works to my expectations.

Interested in the results, a few months later. So... did it work?

 

The proposed circuit by jjj have a few flaws:
- One cannot place a 13V zener directly across a blocking diode, since the battery voltage reaches 14.5 VDC when the engine is running, "it would release its precious smoke that makes it work", meaning it would burn up, because there is no current limitation after the
blocking diode !!!
- The Mosfet transistor would pick-up the power relay as soon as the power is provided to the circuit, imobilizing the the vehicle immediately !!!
- This circuit needs more work and more thinking !!!

Good luck

 

The proposed circuit by jjj have a few flaws:- One cannot place a 13V zener directly across a blocking diode, since the battery voltage reaches 14.5 VDC when the engine is running, "it would release its precious smoke that makes it work", meaning it would burn up, because there is no current limitation after the blocking diode !!- The Mosfet transistor would pick-up the power relay as soon as the power is provided to the circuit, imobilizing the the vehicle immediately !!!- This circuit needs more work and more thinking !!! Good luck

Thank you for your good advice. For a professional like you it should be an easy task to perfect it. I have only hobby electronics knowledge and so, you suggest I have to struggle myself to perfect the circuit? - At 74 it's not that easy my friend, but anyway I have no alternative...
I must have looked up the placing of this 13V zener wrongly...
Please be so kind to continue to at least verify/ criticize my solution to the problems, so that I can finish my project successfully.
My solution to the problems is:
1) ... to replace the Zener with a 12V positive regulator and that should limit the voltage to the circuit at +12V.
2) ... and with the voltage +12V limit I also killed the second ("fly") problem you mentioned, for at stable voltage the circuit will be stable!
Thanking you, (apparent email address removed by moderator -dc)