Ideas for LED desk lamp

[vodokotlic]

My primary light source while doing computer stuff is (or at least was, until it died last night) a flexible desk lamp powered by a standard E27 socket 20W 865 twisty CFL.

CFLs death made me think. I've tried searching the forum for DIY LED desk lamp projects but nothing useful came up, and anything factory made is just sad and/or shockingly expensive. Obviously, I'd like to improve on existing setup i.e. equal or higher output, several output levels or even continuous control , CRI in the 80s or better, 5-6000K

Looking through my electronics parts bin I found a switching 12V DC 2.5A power supply, a 120mm computer case fan bolted to a matching Al heatsink (120mm x 120mm x 25mm) and of course the existing lamp.

My first thought was to get a multi mode driver for a flashlight and 2-3 XM-L stars I'd bolt to the heatsink but for starters I'm unsure of what to look for. I've managed to get a hang of tint codes but CRI is a whole another story.

Please enlighten me :grin2:

 

[Steve K]

I did make a desk light using six XP-G LEDs....
http://www.flickr.com/photos/kurtsj00/sets/72157628336517483/

I used an old power supply from a scanner, and made a simple current regulator for it. It works fine, and use it every day.

Since then, I made a replacement for a 100 watt incandescent bulb for a table lamp. It uses three Seoul Semiconductor Acrich2 eight watt modules.
http://www.flickr.com/photos/kurtsj00/sets/72157632507952012/

I've been very happy with this, and I'd recommend the Acrich2 modules for a lamp like yours. It's very simple in regards to electronics. Just add a fusible resistor and MOV for protection from voltage surges, and implement suitable heatsinking.

 

[snakebite]

i have done a few 12vac halogen lamps with a bridge,3300@16 low esr cap,large chipset heatsink from a junk motherboard,and a altilon 1x4.
.27 1w as a current limiter and fuse.i dremel off the top of the shade to suit my heatsink.i then cut the reflector to clear the led.when its perfect the heatsink will sit on the reflector.its thin aluminum.led mounts to the heatsink.i paint the inside of the reflector white.jbweld attaches the heatsink to the reflector to use it as a small heatsink iself.
about 800 lumens+-.
bridge,cap,and resistor in the base on secondary of transformer.
getting ready to do a lightolier "baton" lamp with 2 altilons.
did one up because i was told by several so called pro's that it cannot be done.
and several friends saw it and wanted one.so i built a bunch.all still going fine.
most lamps using the 12v bipin lamp will work as well as older ones using a #93.
biggest challenge is to have it look nice at the end of the job.i lucked onto some old p90 heatsinks that look like a stack of disks.the first comment was that the lamp reminds them of something from the jettsons!

 

[Julian Holtz]

Hi!

Maybe this will provide some inspiration:

http://www.candlepowerforums.com/vb...ith-2x-50W-Epistar-LEDs&p=4157661#post4157661

http://www.candlepowerforums.com/vb...with-awesome-brightness&p=3945157#post3945157

 

[mds82]

There are also plenty of LED bulbs out there that are pretty good and inexpensive.

 

[Tana]

Would this adapter be good for running 3ea XPG's or Nichia 219 in series ???

https://www.fasttech.com/products/1159900

I'm still trying to figure out which power adapter to use to run lights in bathroom above mirror... this seems nice and cheap... anyone has any opinions of it ???

 

[Illum]

Well, I personally find that a single XP-G providing light at 1000mA is the best trade off between heatsinking, efficiency, and light conservation. With a mule setup I can read on a table while providing little to no glare to whoever that's sleeping on the bed behind me.

The foundation of my lamps is the Littlelite® L-series gooseneck, which could be had used for under $10.

The driver is the well known Luxdrive buckpuck.

Surplus heatsink, drill a 1/2" hole to fit the gooseneck, o-rings help keep it snug but still enables turning.

some weights, a spare junction box, and a 12V reglated psu... voila!

CREE XP-G NW R2 bin [112lm/W], puts out just short of 300 lm. The device can run on a 6V lead acid, 7.2V NIMH, 8.4V Li-ion, 9.6V NIMH, 12V lead acid, and 24V lead acid batteries just fine. runtime varies with capacity. With the 8-cell battery pack shown the light will run for up to 5 hours.
The heatsink ever gets past "warm" and if one really wants to, buckpucks can be used with a switched potentiometer to achieve infinite levels of light. Just make sure your switch is "open" at the end of the turn. A "closed" switch turns the buckpuck off.

I have these all around the house, with different tints. Usually XPG NW, but recently using Nichia 219s here