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Car Immobilizer problem

amidis86

Jul 17, 2012
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Hello, i just follow simple circuit to make car ignition cut off, in this circuit when button press, relay will give signal to second relay, and the second relay will self hold. But the problem is, when i start car ignition switch, the self hold relay terminated.

Ignition.jpg


So i replace self hold relay supply with direct battery, the problem is i need to add some switch to cut the hold relay. Anyone have circuit that off delay switch will so i can apply to cut off the direct supply line?
 

mechtronics

Aug 7, 2011
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which relay do u want to decouple the 12 volt supply relay or the other one? and do u want to do this automatically? after a certain time?
 
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amidis86

Jul 17, 2012
47
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Here is my idea :

Ignition.jpg


Ok here the process:

When i press the switch(This will be my ignition switch), first relay on top will on, and then second relay on bottom will self hold.(This self hold relay will be connect ignition coil wire)


But when i put ignition switch to start, the self hold relay that hold ignition coil line automatically lose power and not hold any more.

Then i replace self hold relay supply with direct 12vdc from car battery, but i need to put some switch to reset the self hold relay. What i want is i dont want to use reset switch, i want the self hold relay automatically reset when i switch off the ignition switch
 

mechtronics

Aug 7, 2011
153
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so while you have the ignition switch on the self hold relay will hold. and you want to break the circuit to turn off the self hold relay while you still have the ignition switch active?
 

mechtronics

Aug 7, 2011
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i may have an idea that involves another 4 pin relay and a 555 timer circuit that might be able to be added to it. i will put up a block diagram and show you if you want?
 
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amidis86

Jul 17, 2012
47
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i may have an idea that involves another 4 pin relay and a 555 timer circuit that might be able to be added to it. i will put up a block diagram and show you if you want?

Yes please,i want it. i can try it, any possible circuit will be so thankful :)
 

mechtronics

Aug 7, 2011
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is your ignition switch just going to be on for a few seconds or what? according to the diagram it has to be contantly on?
 
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amidis86

Jul 17, 2012
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is your ignition switch just going to be on for a few seconds or what?

I'm sorry, my bad explanation, here the full description on my project.

1. Ignition switch pull to ON position, RFID System ON, engine cannot start

2. The switch on picture will be rfid scan signal,, when i scan rfid card, 12v will be supplied to top relay, and automatically bottom relay will self hold. <--bottom relay hold using direct battery

3. After bottom relay self hold, i able to pull ignition switch to START position. engine start. If i switch OFF ignition switch engine stop, but the hold relay not reset until i disconnect the supply.

Any suggestion how to make the hold relay reset automatically when i switch off ignition switch without using switch?
 

mechtronics

Aug 7, 2011
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how will the relay be able to self hold when u pull up the ignition switch that cant be possible. it will disconnect anyway
 

amidis86

Jul 17, 2012
47
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Jul 17, 2012
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i may have an idea that involves another 4 pin relay and a 555 timer circuit that might be able to be added to it. i will put up a block diagram and show you if you want?

Can Timer 555 use as, when got supply the timer is ZERO, but when no supply, it hold a relay 15-30second then de-active the relay?
 

mechtronics

Aug 7, 2011
153
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what i mean is when u scan rfid this switch will have to be contantly on to keep battery supply going through the relays.
 

mechtronics

Aug 7, 2011
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in your diagram is your ignition switch in the top left corner the same as the one u have pointed out going to the battery??
 
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