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I've purchased a small WS2811 5050 RGB LED strip. I want to light them up without any controller currently. But I'm struggling to do that.

The strip I'm using:

http://www.ebay.co.uk/itm/201709948864?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

I've got a 12V Switching Mode Power Supply (L06BR) connected to both positive, and ground of the strip (both sides). And I get nothing?

Not sure what I'm doing wrong here, do I need a controller to simply power it up? Maybe the Amps are too low? Running off 1.7A - but I gathered I don't really need that many amps to power a 48 LED strip.

I would like to eventually hook this up to my Arduino and get some colour changing on the go! :)

Thanks.

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Those LEDs need a controller to do anything, their default state is off.

You send them a serial data stream of 24 bits (8 bit Red, Green and Blue) per LED. The first LED in the chain takes the first 24 bits and uses them to set its color, it then outputs any further received data to its data output pin which is connected to the data input of the next LED. This way you can have a theoretically infinite length chain of LEDs, each set independently, driven from a single pin.

If the data line is idle for a 50us the data pass through mode resets and you are back to setting the first LED in the chain.

The timings required for reliable data transfer are fairly tight, on most micro controllers you generally you either need a library written in assembler or you can use an SPI bus interface and play some games with the data format to generate the correct timings on the output. There are libraries for the Arduino and other platforms that will handle the timing for you.

It would be possible to set them all to white and full brightness using a PWM output if you set the duty cycle and repeat period correctly. I have a 300 LED strip (with a little bit of coding they make good Christmas lights), all on full brightness pulls about 7.5 A so your power supply should be good for 48 of them.

The full data sheet is here: http://www.world-semi.com/details-106-4.html

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  • \$\begingroup\$ Hello, thanks for your reply, very informative. Will I still be okay running from 1.7Amps on 12V? \$\endgroup\$
    – Oliver Jones
    Dec 16, 2016 at 14:06
  • \$\begingroup\$ Yes, your supply should be ok. \$\endgroup\$
    – Andrew
    Dec 16, 2016 at 14:13
  • \$\begingroup\$ thanks for your feedback. I shall keep my power supply as it is. Now, regarding the controller (in my case Arduino), I am very much a newbie, and I'm using this project as a learning curve. So I apologise if I come across rather idiotic. But is there an Arduino script example I can use so I can play with it, and see how it all works? I don't really understand the timings, and data transfers. Thanks. \$\endgroup\$
    – Oliver Jones
    Dec 16, 2016 at 14:14
  • \$\begingroup\$ You'd probably have better luck asking on the arduino forum but learn.adafruit.com/adafruit-neopixel-uberguide/arduino-library would probably be a good starting point. These LEDs were branded as NEOPixel by one distributor and the name seems to have stuck, especially in the arduino community, any searches you do you may have more luck using that name than WS2811. \$\endgroup\$
    – Andrew
    Dec 16, 2016 at 14:21

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