Want flashing LED to stay on for 10 seconds

Thread Starter


Joined Dec 22, 2011
I am making a small box that has LEDs on the inside and the outside. I am using a reed switch to make the LEDs inside the box come on whenever the door is open. I have one small flashing LED on the outside that I would like to come on for 10 seconds each time the door is closed. Any advice?


Joined Mar 1, 2009
If it's just a single LED on the outside, I suppose it's possible that if the current draw on that LED is small enough, a fairly large capacitor could be discharged through it which would keep it lit for roughly 10 seconds. Wont be precise but probably one of the simplest solutions considering the component count/cost.


Joined Dec 6, 2011
Can you use a time delay relay? Use the timer for an off delay. I am more into industrial electronics so I hope I'm not talking nonsense to you.


Joined Dec 23, 2011
wjpirates - to clarify -

You want, upon opening of a door (trigger signal), an LED to flash on and off for a period of ten seconds. Is this correct?


You want, upon opening of a door, an LED to stay LIT for a period of ten seconds, at which point, it shuts off.

Do one of those statements accurately describe your problem?


Joined May 11, 2009
yes i want this Led on and off 10 or 5 seconds plz help me:(.
Do not hijack threads! Start your own and post a link as reference if needed. I think your problem can be solved using two 555 timers. One acting in one-shot mode controlling the other that produces the blinking intervals.


Joined Aug 7, 2008
Here's one possible solution. Operating V unknown so some values missing. When SW isclosed, LED's light, C1 charges turning on U1 & U2 which powers up U3; R6 & C3 keep U3 at reset for a blink of an eye untill P2 stablizes hogh. When SW opens, LED's V falls below 1/3 +V, triggering U3 for 10 sec-- I think.