ignition toggle switch with spdt relay, micro controller, and 5 but transproter style

[Annonymous]

I AM SO FREAKING EXCITED!! Just went to radio shack and bought a bunch of goodies! A spdt(Single Pole Double Throw) relay, 22g wire, a general purpose micro controller, and a 5 button keypad. I am going to hook up the 5 button keypad to the micro controller. the MC to the relay and the spdt relay to my ignition switch. So if i enter the correct code, the relay will close the circuit and enable the ignition. Without the code the car will not start. If you have a non-manual trans you could make it start your car if the code is correct. It should only take a few weeks...HOPEFULLY lol

What do y'all think?

[nonoob]

I don't think a micro controller will power a relay. You may need some transistors and stuff.

[Salem]

Sounds like a cool project.

But you need to see a lawyer and check your insurance before trying it in a real car running on the public highway.

[Annonymous]

nonoob, a micro controller will not power a relay. I have a work around for that.

[Elkvis]

see a lawyer? that seems a bit extreme for just wiring in an extra ignition-disable switch. you're not installing anything that affects the public safety characteristics of the car, so I'd just say go ahead and do it. when the start position in the ignition switch of my jeep stopped working, I just installed a pushbutton. no lawyers, no insurance agents, just a pushbutton.

[Salem]

There is a rather large difference between a passive switch and a bunch of programmable circuitry.

> you're not installing anything that affects the public safety characteristics of the car
Oh really?
Preventing it from starting (when you want) might not be much of an issue.
But suddenly deciding to disable the ignition while driving down the freeway would be a completely different issue altogether.

[Elkvis]

one possible solution to your concern would be a latching relay - one that does not require continuous power to remain in the "on" position. then wire the controller so that it's impossible for it to energize the relay in such a way that it would disable the ignition once it's enabled (a lockout switch), as long as the key is on. regardless, I still don't think that it's especially necessary to get lawyers or insurance companies involved, particularly if you're only doing this to your own car.

[Elkvis]

the even better solution would be just to disable the starter, and not the ignition.