How to make a LED flash once circuit

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Haunted360
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How to make a LED flash once circuit

Post by Haunted360 » Sun Jun 12, 2011 5:53 am

Hi. How would I make an LED flash ONCE when power is connected.

When power is removed, it will reset its memory.

Once power is restored again, it will flash once and only once.

When power is removed, it will reset its memory.

Once power is restored again, it will flash once and only once.


... you get the idea ...


Can it be done with a 555 timer?


Simple electronics yet I can't figure it out.



Thanks.

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com64
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Re: How to make a LED flash once circuit

Post by com64 » Sun Jun 12, 2011 11:54 am

Haunted360 wrote:Hi. How would I make an LED flash ONCE when power is connected.

When power is removed, it will reset its memory.

Once power is restored again, it will flash once and only once.

When power is removed, it will reset its memory.

Once power is restored again, it will flash once and only once.


... you get the idea ...


Can it be done with a 555 timer?


Simple electronics yet I can't figure it out.

Thanks.
It does sound like something you can do with a 555 timer.

I think I did something where an LED (or another circuit connected via relay) turns on when a button is pressed, then fades out as it is released. I can draw out a schematic for you if you want, and you can play around with it. Maybe you can adapt it. :wink:

The transistor is 2N4401. The potentiometer controls speed of discharge.
Image

Oh, here's an idea: find a random 555 timer blinking LED circuit, get it to work at the same voltage as this circuit, connect them to the same power supply, remove the switch on my circuit, remove the LED on the 555 circuit, then connect those points together (ie. via a relay). Might work.
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Haunted360
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Re: How to make a LED flash once circuit

Post by Haunted360 » Sun Jun 12, 2011 10:35 pm

Thank you!

Very helpful.

I will try this for sure.

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Mario
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Re: How to make a LED flash once circuit

Post by Mario » Wed Jun 15, 2011 7:38 pm

You can do it with a 555, if you like. It's called a one-shot circuit.

Here's a good schematic:
http://www.instructables.com/id/Make-an ... hot-timer/" onclick="window.open(this.href);return false;

Just get rid of the "trigger" and wire it closed.
Image

Haunted360
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Re: How to make a LED flash once circuit

Post by Haunted360 » Wed Jun 15, 2011 7:48 pm

Thank you Mario :mrgreen:

*EDIT* Here is the schematic from the site it was pulled off of (links shown in the image)
Image

Some helpful links
http://www.mds975.co.uk/Content/components01.html

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evilteddy
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Re: How to make a LED flash once circuit

Post by evilteddy » Sat Jun 18, 2011 5:36 pm

Just use a monostable multivibrator. Likely you'll only need components you have hanging around.

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