Finally did it - Luxeon 3 desk lamp

Bought a TY0L star, stuck the thing on a CPU heatsink and stuffed it into a desk lamp.. /ubbthreads/images/graemlins/smile.gif

I was looking for a power supply for a long time, and I found a couple of unregulated wallwarts that needed an LM317 to provide the correct amount of current to the Luxeons. However, there turned out to be an easier solution, because I found an Iomega Zip power supply from a long-departed Zip. This supply delivers 5V at 1A, is regulated, protected against open/short circuits, in a nutshell, it's all I need. I went with the resistored approach to bring current down to appropriate levels and it works beautifully.

Another feature I added was a Molex connector - I put one on the power supply and one on the desk lamp side, so that I can power the desk lamp by tapping a 5V feed from a spare computer power connector, thus saving myself an AC outlet. Or, if no computers are handy, I have the power supply.

Pix to follow when I get them done..

Great idea. Any plans to make its brightness adjustable? Of course for that you would have to use that LM317 and a pot, but that would be handy.

Great way to reuse unneded tech parts!

It's funny, I've been collecting parts to do something similar, but this would be a 1 watt powered by batts. I was looking at the Fatman board for it. Anyone tried these? Thanks.

DasFX

Another good option is to use a mobile phone charger. I have an Ericsson charger... 4.5V 300mA. Regulated /ubbthreads/images/graemlins/thumbsup.gif There are various chargers with different outputs. Excellent reuse!

I have a 20 led bulb that you screw in from the ccrane company. I like it as it has that bluish color, but it does have a rather spot, not a flood of light. I wouldnt mind seeing you photos if not a beam shot. THis sounds like something i would be interested in. Heck, I spent 70 bucks for that bulb.

The battery powered idea sounds neat too. I have been suing my xpg on low as a reading light. Before hand I used my 20 led light with my inverter on my wheelchair, the 19 led light from ccrane and before that a 55 watt fog lamp mounted on a clip on lamp neck with cooling fans that was powered off my wheelchair too.

I have the 20 LED Ccrane lamp also. I thought the LEDs were horribly under driven and in afterthought, a rediculous price of $60 (or did it cost more?). Also the term "reading" lamp is correct, you really need the lamp close to your source to read. I bought mine a good two years or more so maybe it's changed.

I have been wanting to make an LED light for some time and have heard of using mobile phone chargers as a power source. What do you plug the power source into to split the current to positive and negative wires which feed the luxeon? Maybe the pictures will help.

StanTeate

Wow, I never imagined there'd be so much interest. Now I absolutely have to take pictures. Thanks guys! /ubbthreads/images/graemlins/smile.gif

Just before we get to the photos, the specific replies:

jbev: That's an idea, the lamp may probably get an upgrade later in life. It will also produce less heat for more runtime, and adapt very well to batteries.

hotbeam: That was suggested to me too. A Nokia charger puts out 700mA, nearly 6V on a short circuit. Unfortunately I couldn't spare any of my phone chargers.

General notes:
The advantage of the Zip was a whopping 1A of current so I could really blast this Luxeon along at 1.2A. It will shorten its life, heat up the heatsink A LOT, but heck, by the time two years go by assuming 1 hour of use per day (realistically, it gets 15 minutes on average), LumiLEDs will probably be offering VY0K Lux3 bins or something, so I'm not worried.

You can buy barrel connectors to fit the stock Zip plug, it's a very standard connector that seems to go with everything. However, I chose to chop off the barrel connector and solder on male and female Molex connectors so as to be able to hook this one up to a computer, and other battery packs I use. My first ever project involving a Luxeon was a 1W lantern with 4AA battery pack and integrated resistors that gave me ~320mA of drive current. I should really try that pack out on the lamp. This enables me to be very flexible in my power options.

With an LM317 I can 'dial in' the exact amount of light, right now I am using resistors, additional resistance inline with the power source. 4-cell D or lantern battery with resistor for additional runtime, no resistor for full throttle 1.2A operation.



Never thought taking pics of a lamp would be so hard either.. /ubbthreads/images/graemlins/smile.gif

Some other build notes - the lamp was expensive, all of $4.99. It didn't even come with bulb /ubbthreads/images/graemlins/grinser2.gif but.. but.. I already have a bulb! It just doesn't fit the stock holder! /ubbthreads/images/graemlins/grin.gif

Of course, being a light, it has a switch. I cut the two-pin plug off the end and soldered on the Molex, as shown below, so I can use the factory switch which has a very nice smooth feel to it. Construction of the lamp is quite solid and very reasonable. The head is made of blue plastic.

Initially, I thought of drilling a hole in the side to push a screw through into the heatsink to hold it, but apparently it can be wedged very tightly with some force, and doesn't come out.

That is a 0.56 ohm resistor. Current consumption is estimated at 1.1-1.2A. For those who want to build a custom switch system, it is possible to get two switches, when you open one, it connects a path with one resistor, when you open the other, it connects another path with a lower value resistor (to make it brighter, ie. medium mode), flip both switches to open both parallel paths and get max mode.

I think it would serve quite well as a reading lamp, it's as powerful as the awesome TW0L Mag4D of the OA4D Cookbook, except that with no reflector, it produces a much smoother flood beam. The beamshot shows the desk lit by the lamp alone, it looks brighter in real life. It's nice and bright for reading at up to 3-4ft away.

This does not preclude the use of extra optics or reflectors. I get the full lambertian radiation pattern since it's a HD, yout you could always capture that with a SO17XA to produce a nice concentrated beam pattern that is still wide angle enough to be useful.

The TY0L really brings out the blue color in the surrounding objects. Very cool light. W0 would be fantastic but they're hard to get. I have also worked with TV1Ks before, if you prefer the opposite end of the spectrum.

Per usual, I took a really easy idea and made it harder than it is. A pic is worth a 1000 words. Thank you.
Have you seen the lamps at the Shoppe?
http://secure3.dnsaction.com/~anlighte/shop/product_info.php?cPath=48_71&products_id=310&osCsid=419a26060a9961f0e4391613a06f3257
A bit more expensive but worth considering?

Yeah, the bulb I have does get warm after some use. I tried it else where, but its light is too dim and in a spot like beam to use anywhere else other than a reading light.

Wow, that light looks white and pure. How much does those bulbs run? I see the link points to a 50 buck light.

The loc-line solution at the Shoppe looks very professional indeed, and it would mount in lots of places this lamp wouldn't go. It's smaller, too, if size is important to you.

This is a Y0 bin, and every LumiLEDs Lux3 bin with a 0 is very close to white. However, the Y0's are still classified as slightly off the Planckian locus, they're a little bluer than pure white. It's not bad if you like the cooler color which seems to have slightly better contrast (subjective observation). The TW0L I have looks substantially warmer side-by-side. If you want neutral white, I still recommend a W0 bin, and if you want something on the warm side, a V1 bin. I bought mine from oeo2oo who still has some TY0Ls and TV1Ks.

Another idea which just occured to me, if you are going for absolute maximum light, direct-drive two of the stars off the 5V Iomega Zip power supply in parallel. I have found that without the resistor, I get 1.5A passing through the TY0L, so you could concievably use two stars in parallel and push 750mA through each of them. This would result in more light and less heat, as McGizmo's detailed charts show.

Based on his readings, his setup at 0.75A scores 4296 lux (note: lux readings between his test rig and this lamp will of course not be directly comparable, but the idea is to look at the ratio). Going up to 1.2A gets 5435 lux.

Dual LEDs in parallel would give 4296 x 2 = 8592, an increase of 3157 over spending the extra energy driving a single Luxeon harder. We have a little more room to play with desk lamps than portable illumination.

dasfx: I see you're going for the regulated/dimmable solution. All the best with your project!