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Author Topic: Just seen on aliexpress...  (Read 1073 times)
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Valencia, Spain
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Check it out!

http://www.aliexpress.com/item/New-Arrival-16-16-Pixels-WS2812-Chip-WS2811-IC-LED-Digital-Flexible-Panel-Ligh-DC5V/909915629.html

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Also this:

http://www.aliexpress.com/item/1M-WS2811-Dream-Color-LED-Strip-Lights-144-Pixel-5050-RGB-SMD-WS2811-IC-Per-Meter/942669737.html
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The strip lighting says that each light can be controlled individually; could something like a TLC5940 be used to control 16 of them?

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The strip lighting says that each light can be controlled individually; could something like a TLC5940 be used to control 16 of them?

No, they don't work like that.

Each LED already has a controller chip inside it ("WS2811"). You communicate with the string/matrix (using a single Arduino pin) to set the color of each LED.

You can also chain strips together and control them all like one long strip.
« Last Edit: June 02, 2013, 03:24:04 pm by fungus » Logged

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Thank you very much; that is some awesome news for me.
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wow they look cool, shame they are not slightly cheaper though!
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slightly cheaper?

32 leds per m is about $10, 64 $20, and these are 144 @ £38.

these are in line for the resolution.

good luck getting efficiency with arduino though...

teensy 3 mind!

 
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26 cents per LED is plenty cheap for these. Those things cost about 50 cents/LED a few months ago.

(and if you order 2 meters or more they work out at 24 cents/LED...that's about as cheap as you can currently get for WS2811 LEDs)

It's a shame the 16x16 panels have a wide border around them so you can't tile them to make huge displays. I guess the next generation will fix that though...

« Last Edit: June 03, 2013, 05:53:33 am by fungus » Logged

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good luck getting efficiency with arduino though...

teensy 3 mind!

An 8MHz AVR can drive a WS2811 strip at full speed...why not a Teensy?

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for clarity, the teensy3 will be able to quite easily... not so much the arduino
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for clarity, the teensy3 will be able to quite easily... not so much the arduino

I dunno. Getting the timing right might be more difficult on a Teensy than an 8/16MHz AVR...
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then you need fast spi 2 which has just been released (rc version anyway!)

makes the timings easy peasy!

http://code.google.com/p/fastspi/

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i have been reliably informed that you can get about 100fps on simple animations, and about 30fps on complicated ones... this is assuming 256 leds in a single string (like these things technically are)
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i have been reliably informed that you can get about 100fps on simple animations, and about 30fps on complicated ones... this is assuming 256 leds in a single string (like these things technically are)

The refresh rate doesn't depend on the host CPU unless your animation needs a lot of processing power (eg. decompressing a video).

The usual bottleneck is the WS2811 chips inside the LEDs, they need to be fed data at about 800KHz, no faster, no slower. It doesn't matter if you're using an AVR or an ARM, the strip refresh rate will be exactly the same.

256 LEDs will take 7.7 milliseconds to update (call it 8ms because you'll always have some small losses because of loops, etc.). If you can update your animation in 2 milliseconds then you'll get 100fps update. To get 30fps you'd have to take 21ms to update the animation, that's 1300 clock cycles per LED on a 16MHz chip, which is a lot of processing...

All that aside, those things are cool...! Who cares if there's an AVR or an ARM driving them?

« Last Edit: June 03, 2013, 01:45:22 pm by fungus » Logged

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Hi! I wrote and maintain the FastSPI_LED library. Working on trying to keep it up to date.
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I can verify that the 16x16 arrays work really well w/FastSPI_LED2 from both arduino and teensy 3 - it's what i've been using as a portable test platform for the past week or two while wrapping up the library.  (I have other led strips/chipsets that i've been using for testing here and there, but the 16x16 is my go to for work right now).

Also - man, 144 leds/meter - this stuff is getting dense! 

I really want something like the ws2811/2 packaging but with lpd8806's performance and maybe with tm1829's ability to do constant current brightness instead of pwm....
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FastLED (formerly FastSPI_LED) -- new home http://fastled.io

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