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Permalink Reply by Dan Sleep on November 22, 2012 at 1:23am

I had seen this one already, but I had trouble sourcing the magic smoke.

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Permalink Reply by Thomas "Duck" Petry on November 22, 2012 at 7:24am

Easy enough, just get a jar of this stuff.

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• lucas service part.jpg, 22 KB

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Permalink Reply by John Robbie on November 22, 2012 at 1:11am

Hey Dan, give this a crack, the pot on the left side controls the time it is activated and the relay switches between solid on and flashing.

The pot on the right hand side controls flashing speed.

It would work with 9v too without an issue.

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Permalink Reply by Rand Moore on November 22, 2012 at 1:14am

Seriously, Naz!

I'd Google "555 timer chip" and check the electronic circuit sites to see what they have that might match what you are trying to do. I did a quick search and came up with this link which describes a basic circuit using a 555 to flash a LED. They are driving the LED directly, and I'm not sure how many LEDs you can drive with a 555. You might need a transistor switch to buffer the 555 output so it can drive more LEDs. The article also gives a formula for calculating the frequency of the 555 timer's output. In any case, you'll likely have to do some experimentation. Wikipedia says the 555's V_CC can be between +3V to 15V DC, so you should not have any problem supporting the circuit with a 9VDC battery.

-Rand.

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Permalink Reply by John Robbie on November 22, 2012 at 1:23am

True, the current draw could kill the 555, also I prob should have added a diode to protect pin 3 of 555, anyway its a starting point.

I have run 555s at 9v, never for too long though really, 6v would be a safer bet for longevity for sure, if Dan is not wedded to using a 9v battery.

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Permalink Reply by Dan Sleep on November 22, 2012 at 1:28am

The LED manufacturer suggested that I use a battery pack that puts out 12v for maximum brightness, so I am leaning that direction, so whatever I use will need to work with 12v.

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Permalink Reply by Dan Sleep on November 22, 2012 at 1:26am

Thanks Rand. I had done quite a bit of reading on the 555s. What I have is a commercial flashing module that I intend to use, so all I really need to do is interrupt the DC voltage for a few seconds.

Instead of using the 9V, I am probably going to opt for a battery pack that uses AA or C batteries. I think that will give me a higher mah rating which should make the batteries last longer.

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Permalink Reply by John Robbie on November 22, 2012 at 1:28am

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Permalink Reply by John Robbie on November 22, 2012 at 1:30am

200ma would be the limit directly driving from the 555, schematic updated to protect 555 and show maximum current draw.

Might come in handy down the track somewhere.

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Permalink Reply by Dan Sleep on November 22, 2012 at 1:32am

I plan on using this module:

http://www.superbrightleds.com/search/led-products/lsc-100b/

with this LED strip:

http://www.superbrightleds.com/moreinfo/top-emitting/wfls-x-bk-seri...

My thought was to connect the switch to the whole unit, so it turns on and flashes when the switch is tripped, flashes for 5 seconds, then turns off.

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Permalink Reply by John Robbie on November 22, 2012 at 1:45am

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Permalink Reply by John Robbie on November 22, 2012 at 1:47am

the pot controls how long it flashes before it turns off, use a 6v regulator to get the voltage down for the 555 and you can run it all off the one 12 supply

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