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Using High Power LEDs to Make Lights

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WooferHound:
For the last week I have been using this little lamp I made to that will light up my computer desk which is also a small workbench a lot of times. It is attached to a lighted magnifier. The wiring is temporary for now but I use this light all the time now.



Basically it's LEDs glued to a CPU Cooler that has been mounted inside of a small 3 inch PVC pipe ring. Two power feeds, one for the LEDs from the buck converter, and another feed from the 12v solar power to the fan through an 82 ohm resister so it is slow and quiet.



There are four 1w LEDs glued into the 4 corners so the light will come from a wide area and soften the shadows that will be created from it. Two LEDs are Warm White and the others are Natural White, wired into a series/parallel arrangement, making it 7 volts at 700ma or 4.9 watts.



I have so much of this LED stuff going on that I have decided to build a box with 4 buck converters in it to power some more lighting that is planned after the Mail runs today with another pile of LEDs to play with.



The picture above was taken using this light and the camera white balance set to Incandescent. You can see  the Soft Shadow effect from the box.

Pete:
Hi Woof, I also have one of those magnifier lamps. I took the flouro tube out of mine and installed LED's. I bought some that were three leds on a strip and they had plugs that allowed them to be paralleled. They came with sticky backs so I just stuck them around the inside of the lamp where the tube was, junked the mains parts and connected it to 12 volts. Works great, probably not as bright as your newer LED lamp though.
Great to see someone having fun
Pete

WooferHound:
Well . . . I thought about it too much and decided not to make a box full of Buck Converters, instead I made some individual boxes that are attached directly to the lighting that they control.

The box on the left has 2 buck converters in it which will control 2 lights on the Lighted Magnifier pictured above, including the PVC Tube Light also in the story above. The other light will be on the Back Rail supporting the magnifier and will face up toward the ceiling for some indirect uplighting. There are a couple of Air Holes drilled in the box for cooling but it doesn't really get warm.



The Box on the right has a single Buck Converter in it and powers a couple of white LEDs that light my Computer Keyboard from above. Two normal 20ma LEDs in series so only 20ma total. Then I tried to set the buck converter to 20ma there was an odd flashing effect. Tried several things to fix it and it finally worked OK at 20ma with a 1000mfd capacitor across the output.

I was having trouble with some projects using the Buck Converters around fans where I could see a slight strobing effect, indicating noise and flashing. Was also getting a high frequency tone through my 12 volt sound amplifier. I have found that a 470mfd capacitor across the LED will stop those problems.

WooferHound:
I have been working a lot lately and haven't done much with the LED lighting, although I have been experimenting with the High Power Colors that arrived in my last package.


Here is 1w Blue and Red Together. Getting ideas for Nightlights here


This is 1w Royal Blue. A really interesting color between Blue and Ultraviolet


And this is a small circuit board with sixteen 5mm Ultraviolet LEDs soldered to it


I also have several projects started which will provide strong White Light. This is a test of a triple-brightness lighting fixture being constructed to mount to the ceiling over my computer desk/workbench. It has a 5 watt LED for the Low level and four LEDs that total 10 watts for the high level. so it can be switched to 5/10/15 watt levels. It sure is bright and competes with Sunlight coming through the window.

 More to Come . . .

solarnewbee:
Hey Woof!

I have installed and repaired many outdoor 100w led floodlights of the Chinese persuasion and they use the case as a heat sink and use thermal paste under the led and screw it down. The led’s are the same like the 20w you show in the pic. I have used a thermal glue to attach waterproof Dallas temp sensors to my inverter and find it works quite well. I just bed the sensor in a glob of it and masking taped it in place for 24 hours. Not as fast as epoxy but I feel like it conducts heat better. Of course the fixtures I installed had a flaw in that the case had minimal fins on the back and the entire surface area was only 10”X10”. This may be why they failed so often or power surges lightning. I did install a a high quality surge protector on the parking lot lighting system and failures have slowed.

I wonder if you were to epoxy a 100w led to a heat sink that it may begin to melt the epoxy? There are scew holes so maybe consider drilling holes. I designed and built a dump load for my windmill and drilled holes in the heat stink, thermal past under the resisters and small screws.

Like your projects. Keep on keeping on bud!

SN

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