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3 Watt $8 Mini Strobes


RoadRanger

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(Moved from another topic a few days ago) :

I've ordered up some generic versions (from fleaBay) of these $15 strobes to attempt to convert to continuous operation - red, blue, and yellow:

http://www.amazon.com/Chauvet-Lighti.../dp/B004A8ZNC8

I'm hoping I can just short out the strobe switch transistor in them or ? Maybe red on one side and blue on the other, with the yellows for front lighting turned down somehow - maybe pull some of the LED's?.It'd be way cool if I could convert the strobe speed into a dimmer smile.png .

We don't really need/want much light (older guys LOL) - maybe put a couple SlimPar 38's on the floor in the back on auto, uplighting the banner like I normally do elsewhere...

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Got them in. I didn't delve into the circuit but it appears to be a simple scr running off the raw output of a bridge rectifier driving the 24 LED's (all in series) with a (1 w ?) 30 ohm "ballast". So, my tentative plan of raising the strobe frequency range to simulate a dimmer wouldn't work and I'm not ambitious enough at the moment to convert the circuit into a true dimmer so I just shorted out the scr and tried it. All was fine until the LED array started smoking after a while eek.gif. So, I lifted one of the diodes in the bridge rectifier to reduce the average current in half and so far it's working although the left over odor of smoking plastic would mask any pending doom facepalm.gif. I did verify that the ballast isn't getting even warm - probably the "right" thing would be to increase the value of that and leave the bridge operational? The increased flicker of running at 60 Hz vs 120 Hz is noticeable but not obnoxious.

 

The first one converted is a blue one and the output is pretty low, no need for any dimming. The spread isn't as wide as desired but if needed I can replace or overlay the clear plastic front with some sort of diffusor.

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Oops, found the source of the smoke on the second one (which smoked even with the bridge diode lifted) - there's another series resistor (1/4 watt ?) tucked away on the LED board where you can't quite see it. Unfortunately that board is hot-glued in so a bit of a PITA to get at the resistor to change it out for one of the proper rating and/or to move it a bit so it doesn't touch the plastic case. OTOH this is promising to let me up the brightness and frequency back to "normal" smile.png .

 

LATER> Looks like I can bypass that resistor and either add another between the flasher and LED boards or just change out the main 30 ohm one on the flasher board. I do see that the LED board has a "3K" marking for the one there...

 

Oh, and the second one was a yellow one - yellow LEDs have a smaller voltage drop than the blue ones on the first so that would explain the difference in smokability wink.png .

 

Anyways I ordered up some 5W 3K resistors (60 cents each) . Lots of empty space and ventilation in these so shouldn't be a problem to mount them smile.png .

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  • 2 weeks later...
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Well, those sure are the dimmest lights ever LOL. About 1.2 actual watts. I haven't quite made up my mind if they are usable as front lighting - they'll end up used for something else if not. Turns out that series resistor was a 2K on them and I used a 3K - but since I am running continuous that's right at the 20ma the LEDs are probably rated at. The blue ones have a higher drop so a bit less current but they are actually significantly brighter that the others...

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