Several high power LEDs made into pixels

[robt]

I've been dabbling with light strips for a few months, bought two about a year ago, and just recently started having time to learn how to control them. I picked up an e6804 and a few other things that should be here soon.

The strings will be really useful for some things needless to say, but there's an area that i want to learn, but see very little info on, maybe i'm just not looking in the right places. Rather than hijack threads for bits of info here an there, i made this one.

Obviously, these are much higher power than the strips/strings people generally talk about here, it could be that i'll find more relevant info on other pages, any info would be fantastic!

Thanks,

Rob T.

 

[Beefer]

For individual LED control, we rely on a single dedicated chip or integraded circuit for each group of red/green/blue LEDs which is built as part of the pixel strip or string.

What you're trying to do is to is to do something similar by grouping high-powered LEDs into a controllable pixel, which would need its own chip.

Actually building that functionality would be tricky, requiring some pretty decent electronics skills on a very small footprint. And then there's the significantly higher voltage to consider which the chip needs to be able to handle.

I think that's beyond the scope of what we do here, as we use pre-built strings/strips which come with that functionality out-of-the-box.

Unless anyone else has seen something that can do this?



Adam

 

[AAH]

Do you want to use them as a RGB pixel driven off a dimmer board or do you want to hook them into a pixel network and drive them as RGB? If it is the 2nd option then my 2811DC15 or 2811DC30 boards would allow you to drive them. The only issue is that once you get over a watt or so with leds they tend to want/require constant current control. The led you use will govern whether need to do this though.

 

[robt]

This looks pretty nice! You mentioned the leds need to be constant current over 1w or so, no problems running 5 or 10 watts? I want to control them via software in an e1.31 net.

One thing i see, it looks like it will only handle 10, but that's more than enough for some projects, i'll have a closer look at these board tonight. Also, not quite seeing, will they work in an existing e1.31 network? Any links to LEDs that have been tested/used would be great too.

 

[AAH]

There's no problem with the board/s driving 5W or 10W per channel. I have used them with 12V led strip which is 180mA per channel or 2W and that's as big as I had on hand. I had 12W of incandescant lights per channel hanging off a few channels while testing too and there is no issue.
To control these board via E1.31 you need to go through a J1 Sys P2 or similar ethernet to pixel board.
There's all sort of RGB high power led stuff on http://www.aliexpress.com/store/group/LED-Flood-lights-LED-wall-washers/701799_209863523.html depending on what it is you want to do with them.

 

[robt]

I have an e6804 on the way. Here's an example of an led i was thinking about driving, i think this would work. If i have it right, your board would drive up to 30 of them? I'm sure i would need two to three times as many eventually, possibly, but this looks great for many of the projects i have in mind.

http://www.ebay.com/itm/5pcs-3W-RGB-High-Power-LED-Star-3-Watt-Lamp-Light-/160971676423?pt=LH_DefaultDomain_0&hash=item257aa8db07

 

[AAH]

Any particular reason you want to go to this style of led. These are the specific ones that are meant to be driven with a constant current drive. They also need to be thermally bonded to a heatsink to get rid of the excess heat. I don't know what other RGB led types are like but these have a large discrepancy in brightnesses
(Luminous Intensity: Red: 45-50LM, Green: 65-75LM, Blue: 20-25LM).
It is possible to create constant current dimming controls for these high power leds so that you can drive them from lor, lsp etc but it gets complicated.

 

[David_AVD]

Alan is spot on. High power LEDs require heatsinks and constant current drive. You can't just hook them up with a resistor and hope for the best.

 

[ron d]

I own hundreds of similar r/g/b,r/g/b/w and r/g/b/a/w lights similar to what your talking about. I can take a shot if whats inside of one or two if it helps. Everything from 18x3 watt individual leds to 18x12 watt 5 in 1 leds.

 

[robt]

I have several myself, i think as far as the electronics go, they're using their own system..

 

[David_AVD]

Ray Wu sells constant current drivers in 2 and 4 channel DMX variants I think. What you want to do is not rocket science, but it's not trivial for a hobbyist either.

 

[David_AVD]

Putting a pixel chip on a PCB is the easy bit. The constant current driver for the high power LED is trickier. Do you have circuit design experience?

 

[AAH]

I might be wrong but I was of the belief that the E682 is a pixel controller. If it is as I suspect then you can't control that 27 channel board with it. You need either a usb-dmx dongle or an E1.31 to dmx board. Assuming you then get the control of the board sorted then you need to worry about driving the LED array. The array doesn't have any current limiting in in so if you tried pumping 12V into them via 1 of the 27 channel boards it would blow immediately. The super rough method would be to put a 5W or 10W series resistor in the line. This method is massively energy wasteful and doesn't drive the LED at a true constant current but it is cheap and it does allow you to control the array with 1 of those boards. If you are planning on trying to use the E682 then 1 of my 2811DC boards is nearly the only board around that will allow you to go from a pixel controller to a high power element like these leds.
I assume a bit and it often comes back to bite me but I myself would assume that the G+ is the unlabelled pad between the R+ and B+ and the same for the G-.

 

[kane]

Just looking at Ray's store, and noticed these. Only 1.4w, but could be an option for you?
http://www.aliexpress.com/item/DC12V-WS2811-pixel-module-with-6pcs-5050-RGB-SMD-LED-50mm-diameter-20pcs-a-string/580547587.html

 

[robt]

Exactly, the e682 is an e1.31 based pixel controller, the 27 channel controller is DMX, and that's works, probably better, since most of the pre-sequenced type software (like vixen etc) won't allow real time control of the lights, i.e. lights respond to sound, only expensive (out of budget) software will do that, as far as i've been able to find.

So, the 27 channel controller is one option to do it, the e682 (or in my case, i ordered the e6804) is another, dmx or e1.31 doesn't really matter to me, as we use both on live shows anyway.

I saw one of your boards when you suggested before, but the channel count was too low for what i need But somehow i missed the aahmega6o version, i'll have to look closer at that one, it looks like it will work better than the 27 channel controller. With the 27 channel board, i can only have 9 rgb LEDs, with yours, if i have it right, 20 will be possible.

I'm looking through the manual as i write this, the more i look the more i think this is far better than the 27 channel controller. If i read right, i think each channel will work up to 2 amps? This might give me enough i think to work even with 5 watt rgb leds(?), which would be amazing.

I'm looking through your original thread at:

http://auschristmaslighting.com/forums/index.php/topic,1990.0.html

It looks pretty amazing really.

Edit

Thanks kane, those pixels though are still based around 1/8th or 1/4 watt leds, far too dim for what i need.