Automatic 555 timer, delay off
I hope someone here may give me a little help, I'm building a car and misses a function.
I need a timer, powered by the engine generator signal D+ (12v). When D+ is on, relay should go on. When engine switches off, D+ dissapears and the relay shold be hold for additional 0.5-2minutes aprox.
Would be nice with a LED saying relay activated. And a switch to stop the timer and power off the relay. I have looked around the internet for a cheap kit or something, but most of the kits is either for 230v operation or with switch activated function.
I thing the timer could be made of a very simple circuit board and a 555 timer. But I'm mostly an expert on automotive electrical wiering and not electronics..
Thanks for any help :)