Alright, I am working on a project and I have a question. This project will need to have a delay (5-10 sec) after the make. Although, I need it to turn off right after activation, with a very short (about a half second) period that it is on. Is this possible, and what kind of relay should I use?

If you need to know, it will have to be able to support 16 Super-Bright Led lights. I do not yet know the power supply necessary, yet.

-AaronG

 

Can you make clear the desired operation of the circuit?

 

The circuit is to turn on 16 different LEDs at once, then turn them off after ~0.5 sec.

 

what input are you giving to enable the output? How long is that pulse? Is it a HiGH or LOW? and once when you get that signal, how long should it wait to enable the LED's? It is not clear from your request.

 

I apoligize for not being clear. Unfortunately I am a beginner when it comes to circuits and have a fairly limited knowledge of what your asking. I do, however, know that I would want about a seven second delay for activation of LEDs. For the other questions, Im not really sure how to answer because I have no idea what you mean.


Im sorry that im a noob.

 

After the 7 secs delay the Leds will stay on forever?

 

After the 7 secs delay the Leds will stay on forever?

No, they should turn off after a VERY short period of time. So that the LEDS make a flash.

 

Im sorry that im a noob.

Hey, everyone starts as a newbie. Noone is a born expert. So dont worry about that.

And about the rest questions I asked, sorry if you didnt understand, but I got my answers. So you give a signal to the LED's, and they wait for 7 seconds and then blink and turn off?? Should they repeat that again and again or only once for each time you give the signal? One more question, the signal you are giving for that output, is it like a flip to on switch or just a push button like one??

 

what are you trying to make?

 

It should NOT cycle, it should only blink once. The project I am working on is hard to explain, but the switch would not actually be a button or switch. It would be two pieces of metal touching, so think of it working as a toggle switch.

 

So the metal contacts will stay touched for a longer time interval than the timer will count?

 

A non cycling circuit is more complex than a cycling one, thats why I asked. Let me see abt it.

 

So the metal contacts will stay touched for a longer time interval than the timer will count?

If by that you mean, when the contacts touch the timer will start counting, then after the delay the LEDs blink. After the blink the contacts are STILL touching.

 

Two 555's or one 556, first gives 7-10 sec delay, second gives .5 sec. driving unknown load. May need driver if load is more than 200 mA.

 

Next try.Two 555's , one for delay, second for pulse.

 

Lots of people ask for a circuit to generate a pulse after a delay. I only know of using 2 555's, but isn't there any easier way to generate that 0.5sec pulse other than a 555??

 

jj, I've looked also. Trailing edge can be difrentiated and used directly for a neg going clock input or fed into schmitt trigger for a few msec + pulse.

 

I've learned in college of using a schmitt trigger, guess that could be done with a diode and cap right?

 

With diode and cap might make a pulse stretcher, but for schmitt, would use 555 or74C14, 74C914, or 40106.