Luxeon K2 LED show-off

A friend (Matt Kocsis) and I purchased some Luxeon K2 LED emitters from Lumileds and I’m looking forward to building some constant current PWM drivers for them. I’ve found a couple of constant current driver schematics, but I’m planning on pulsing the outputs (which can draw up to 1.5A), so I want to make sure that the circuits will work with the high-frequency PWM. Matt and I are also working on a heatsink that will effectively cool these LEDs. The plan is to create a programmable high-intensity RGB spot/wash light with pan/tilt and optic (i.e. focus) control. We’ll see how this project pans out, but in the meantime, playing with these incredibly high intensity LEDs has been quite fun.

The LED emitters pictured below are:

3 x LXK2-PD12-Q00 (Red)
3 x LXK2-PM14-U00 (Green)
3 x LXK2-PB14-N00 (Blue)
3 x LXK2-PR14-Q00 (Royal Blue)
2 x LXK2-PR12-L00 (Royal Blue)
2 x LXK2-PW14-U00 (White)

1 x LXHL-MW1D (White Luxeon Star)

Here are a couple of pictures comparing the different LED emitters:

15 thoughts to “Luxeon K2 LED show-off”

  1. freeride – I just posted some information on the Royal Blue Luxeon K2 flashlight that I whipped together recently. I’ve also made a random RGB color mixer, but I still have to take pictures and video of the setup so that I can upload information about it. The next step is working with my friend Matt to create a full-scale RGB color wash/spot light.

  2. I’m very interested. I’m reasearching for a 12V mobile Luxeon K2 project as an automotive customization. I have two blue luxeon K2’s that I want to use to test. I’m looking for an applicable enclosure and heatsink currently, and I’ve found the one here interesting:

    http://www.ledshoponline.com/MR16K2_led.htm

    It appears to be an enclosure and heatsink. I would like something with optics to focus the output and it also needs to be waterproof. Then comes the task of creating the driver which is a whole nother can’o’worms.

  3. freeride – Ohh, trust me, I do have lots of ideas about your project; the biggest problem is implementing them! I’ve really enjoyed playing around with these Luxeons, but there are a couple of obstacles (some which you you mentioned) that Matt and I still have to overcome.

    The first obstacle that we’ve had to deal with is the driver. Before we go further in the project, we want to have an efficient dimable constant current source for the Luxeons. The most efficient route would be a buck/boost driver. I’ve considered picking up some of the high current LED drivers from Linear Technology, but they all require inductors, which are a pain to find and make (depending on the inductance). In addition, we’ve wanted to breadboard the design before getting a PCB made, but most drivers are surface mount packages. So right now we are considering using LM317s as constant current sources and using MOSFETs to PWM the output.

    The second problem is optics. For your application, are you planning on using both Luxeons as a single emitter source? If not, you can always use separate culminating lenses for each (i.e. Luxeon Collimator, Fraen Focusing, or L2 Lenses) and pot the Luxeon, PCB, and the bottom of the lens in epoxy to waterproof it (permanently!). Our problem is that we want to mix multiple Luxeon K2s (2 x Red, 2 x Green, 2 x Blue, 2 x Royal Blue, 2 x White) in a single spotlight with a single lens. This is turning out to be pretty tough because we need to mix the colors (possibly using a diffuser?) before the primary lens.

    As for the heatsink, we’ve found that using thin PCBs with a copper pour on the opposite side lets us mount small heatsinks to the back of each emitter. We also have some other ideas about using a single active heatsink with multiple emitters mounted to it, but this idea is still in its infancy.

    I’d love to hear how your project progresses. Keep me posted!

  4. Sorry I haven’t gotten back sooner. I’ve been really busy with work and school and haven’t had much time to think about the LED project. It’s still been in the back of my mind though. Are you still around?

    Thanks for the ideas, thats great, you’re helping get my creativity flowing again. Possibly you could mount the LED’s on the inside of a concave structure, maybe using seperate PCB’s for each unit or…

    one PCB with leads from each unit and a seperate heatsink on each unit or…

    possibly the concave structure could act as a heatsink itself. This would allow all of the LED units to point towards one focal point where your optics are located and eliminate the need for a diffuser?

    This may make for a larger unit than what you’re planning on creating but then again it may be able to be done in a relatively small space. I’m just trying to keep the ideas bouncing back and fourth.

    Like I said, I haven’t thought about it in a while so most of the stuff I’ve learned about the project needs to be refreshed. I’m planning to build a seperate unit for each LED. Permanently sealed and 12V compatable so I can mount them anywhere with just a pair of leads to each lamp. Now I haven’t decided whether each unit will have a driver or I will use one driver for all 5-7 units.

    I’m thinking it will save space to use one driver board in an enclosure mounted in a remote location, then the lighting controls can connect to this one unit?

    I understand a little bit but my electronics expertise is rusty. If I could just copy an existing design, then purchase the componets seperately wholesale and solder and produce the replica PCB’s myself then I could make a few of these for my friends which is all I really want to do.

    There are a couple guys that sell drivers on ebay. What do you think of these:

    http://cgi.ebay.com/Multi-LED-Driver-PWM-Timer-Program-0-8A-K2-Luxeon-Watt_W0QQitemZ230068021192QQihZ013QQcategoryZ66948QQrdZ1QQcmdZViewItem

    http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=230108282601&fromMakeTrack=true

    Do either of those look like a realistic approach to a quality product to you?

    I’ll watch for your response.

    Best wishes

  5. Wow, those are amazing! I’m totally jazzed about these Blue XR’s and XR-E’s. I’m working on getting some, I’ve found some optics and drivers for them. Where are you at in your projects? Do you have any of these XLamp LED’s?

  6. Hey, most if not all of your questions can be answered on CPF (Candle Power Forums). It’s the biggest led and flashlight community. Feel free to contact me there. My name there is bombelman. Cheers !

  7. Hey,

    i am in the process of building a super small portable projector. ive been looking into high power led’s as a light source, but ive been coming short on the numbers. according to wikipedia, a 100W incandescent pumps out 1700 lumen. most of the luxeons can do a bit less than 200 lumen, so would i need to band together a couple (like 10), and if so what do you recommend?.

    most of my calculations were based on area that i was hoping to project on (3 foot square screen). assuming that 70 percent of the light passes through the lcd as light, i was aiming at 1000 lumens for pre-lcd power. is this way off base?

    your site’s awesome and ridiculously informative, keep up the great work

    -Dane Kouttron
    http://www.dklabs.co.nr

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