Flashing LED, needed

[planty]

I have a (clifford alarm) led in the wife's car which the alarm has been taken out but they left the led in there, how can i make it flash, Im sure it is a resistor and or a capactor or both, just need to put 12v to it and it will flash, With out taking the led out of the car as it is in pretty tight, it has 2 wires comeing from it, i am going to put it on a relay so when the engine is off the led will flash.
Thanks again, David

 

[Boncuk]

Hi David,

here is a simple flasher circuit. Connect pin 4 as drawn via a relay (normally closed) which is activated with 'ignition on'.

As soon as the ignition is turned off, the LED will blink at a rate of 1sec.

Observe the switch position for ON and OFF as simulated using a yellow LED.

Boncuk

 

[Jarod_C]

The first shcematic Here is a good circuit for flashing LEDs that could make a good flasher for one LED if you just changed the resistor that doesn't have an led to 1k, and short that leg out. And it would still work on 12v.

 

[planty]

Thank you both for youe help, i have tried making one using "Jarod C" but with no luck, will try something else, dont really want to use the 555.
Thanks again, David

 

[HarveyH42]

There are LEDs that have a flash circuit built into them. When you place a regular LED in series with one, both will flash... Cheap ($0.29,or around a dollar at Radio Shack), and a suitable resistor, very simple solution.

 

[planty]

There are LEDs that have a flash circuit built into them. When you place a regular LED in series with one, both will flash... Cheap ($0.29,or around a dollar at Radio Shack), and a suitable resistor, very simple solution.

Cheers for that, will look into it.