Comments on: LED lighting, part 2

By: joel

joel — Sun, 28 Mar 2010 00:51:01 +0000

Dude I’m humbled by your awesome geekitude. But if you’re suggesting a DIY-off then I accept!
We miss you around here man. But it sounds like you’re doing awesome things in L.A. Hope it keeps going well, and your path leads you back to Boston some day…

By: Adam

Adam — Wed, 24 Mar 2010 20:30:45 +0000

Joel, you are a friggin’ animal from another planet. I thought I was getting pretty geeky over here, but you’re taking this to a whole new level. We need to have some kind of “outrageous DIY projects” competition, similar to the ‘stache contest. You may have beaten me out on the facial hair front, but I refuse to be out-geeked by a pretty boy like you… Consider the gauntlet thrown, and if you were here, I’d slap you across the face with a Nintendo Power Glove.

By: joel

joel — Sat, 20 Mar 2010 19:08:46 +0000

Hi Patrick- Thanks for reading! Yeah there’s some info on batching in the Rebel datasheets, which I didn’t really understand until seeing the videos Beth linked to in the comment above. I’m going to try prototyping a fixture with some warm white Rebels, stay tuned…

By: Patrick

Patrick — Sat, 20 Mar 2010 14:13:13 +0000

I’m into quality of light and I have been using filters to manage the color temperature of compact fluorescent lights in my home. I got the idea from when I used FL-D fluorescent filters on my camera to help remove the green from the lights on daylight film, and now I purchased some high temperature ones used for movies and it makes the light the correct balance. It’s basically adding cyan and magenta. I’m not sure, due to the nature of an LED, if it can produce the color of light you are looking for. Have you considered the type of semiconductor material it is made from, there may be purity differences from one batch to the next. Well, good luck and I hope to keep seeing great work from you.

By: joel

joel — Fri, 19 Mar 2010 12:25:02 +0000

Hi Beth- Wow, I think I really bit off more than I first realized here in terms of color/illumination theory, and that first video really made it clearer… thank you so much for the links! You’re right– it looks like the red-green-blue solution won’t work for illumination, unless you add in the other colors as well (per the Mona Lisa example in the video… hmm).

Stay tuned, I hope my project here helps you find a good solution!

By: Beth.

Beth. — Thu, 18 Mar 2010 22:20:16 +0000

Hi Joel, I had just seen your site via hackaday (I previously was here seeing your 55 gallon big black thing ), and you are doing a fantastic work.

Nowadays I’m finishing my home and I always had in my mind using leds for lighting. But with the little free time I have doing some research is hard.

There is a lot of information, led suppliers, electrical and mechanical design considerations, led properties, etc, etc.

And is nice to see your work, as hey I must to do the same before I decide something, I really don’t want a blueish or cold white on my lights.

The low CRI of some leds, high prices of others and such things make me feel lost in these sea of leds, strips, drivers, cri, color temperatures, lumens, lumens/watt, lumens/price, china, … aarrrgg.

Well friend, before boring you, I don’t know if you had seen that but I find it interesting, I got some useful conclusions from that videos:

http://www.national.com/analog/nationaltv

There are a lot of interesting videos there but for leds, “Driving High-Power LEDs Without Getting Burned – Part 1″ and “Driving High-Power LEDs Without Getting Burned – Part 2″ maybe useful for you.

On the first one, the second man starting from the left (green led man at http://www.national.com/nationaltv/abdshow6/index.html , sorry but I don’t remember his name), give a nice explanation about light theory and why colors are not seen the same with led lighting than with sun light.

Also they recommend for RGB applications, using an RGB led for color mixing and a white one when we need white light.

That’s all, nice work and thanks for helping me, this 2700K Rebels seems to be warm enough for me ( I must try them ).

Best regards from Spain, Beth.

By: Matt

Matt — Thu, 18 Mar 2010 19:07:29 +0000

I really like this skillet reflow idea. I’ve been wanting to get some Rebel LED’s, but didn’t think I could handle the SMD soldering.

I’ll definitely kick the idea around now. Any chance you can throw the PCB files up?

Thanks!

By: Jeff

Jeff — Thu, 18 Mar 2010 18:51:53 +0000

You might want to look into the Cypress Semiconductor “EZ Color” LED color “mixing” chips (see: http://www.cypress.com/?id=1579&source=header). They’ll drive bucks or LM3402′s and the firmware and PC interfaces make it really easy to mix R/G/B LEDs into specific colors.