perhaps a transistor and capacitor combo.. it does not have to be precis just a second or two would do

 

What LED current?
What LED Vf?
What supply voltage?
How long an interruption of input power before the next timing cycle?
Can we use R,C, transistor and diode?

 

Arduino?

 

3v (2AA)

yeah i was thinking a resistor/ cap combo would do

using a arduino in this basic application would be like using a shot gun to kill a fly.. it would work but im looking for basic.. as basic as can be

 

... i was thinking a resistor/ cap combo would do...

It will - just experiment. You'll need a relatively large capacitor. If you don't like the behavior you get, you'll have to use something more elaborate.

 

3v (2AA)

yeah i was thinking a resistor/ cap combo would do

using a arduino in this basic application would be like using a shot gun to kill a fly.. it would work but im looking for basic.. as basic as can be

Didn't see in your OP anything about looking for 'basic as can be'. Just responded to what you said with a possibility you could consider based on your stated criterion.

 

Arduino?

Did your last job involve designing modern cars?

 

Did your last job involve designing modern cars?

Nope. Not into plumbing.

 

Nope. Not into plumbing.

Good. I wouldn't want the water in my tail lights to be regulated by a microprocessor.

 

Arduino?

Overkill. A PICAXE would do. 28-pin, of course.

 

Modify the following circuit (you have to adapt it to operate at 3V):

 

use a 2n7002, with a 4.7 M Ohm resistor, a small capacitor will do.

Higher value resistors are difficult to get even though, they exist.

 

hay man it ok.. i should have specified

in fact i'll be using a mp board later in my project

 

Modify the following circuit (you have to adapt it to operate at 3V):

With only 3V, the BJT would probably work well, but at higher voltages I would think a MOSFET would be better.

 

Here is the brute force way, but it has several problems, the least of which is the huge capacitor required. It also has a "recycle" problem, in that it takes a relatively long time for the timing capacitor to discharge to get ready for a new delay cycle after the switch is opened. Note that this is about the best that can be done with this circuit. If you make R2 smaller to discharge the capacitor faster, then it wastes a lot of power while the switch is closed.



Here is a better way. This reduces the capacitor size and improves the recycle time