A question about an LED circuit

[andrew_94]

The circuit I am hoping to build goes as follows

input 5 volts

illuminate LED for 5 seconds

shut off LED

cycle automatically (with the ignition of a car, i would tap an ignition wire)

what would be the best thing to use? a 555 timer?

 

[y2khawk]

It would be reasonably easy that way.

http://pfnicholls.com/electronics/astable.html

Are you picking 5V for a reason? With proper limiting resistor on your LED, you should be able to use vehicle battery voltage directly.

 

[Rookie2]

they make flashing l.e.d's