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I purchased a WS2812B 5050 RGB LED Strip from ebay (http://www.ebay.com/itm/121979001999?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT) and I'm trying to light it up to test and make sure it works. To do this I attached the red and green wires (which should be power and data) each to a 5v power supply and the black wire to ground. I attached them to the side with the arrow facing away from the plug since I think that's where I have to plug it in.
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Since this is an individually addressable LED strip I assumed this would turn all the lights up white, but what happened is all the LEDS flashed for a fraction of a second the first time I plugged it in and then turned off. Since then I can't get the LEDS to turn back on. I'm wondering if I blew the strip, but it says it can support 5v so I don't know how. How would I go about just lighting up all the LEDS white(or just any color it doesn't really matter) on this individually addressable LED strip?

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  • \$\begingroup\$ I have an APA102C strip (similar concept but different LEDs) and it does not light up without a data signal. Are you sure yours does? \$\endgroup\$ – immibis Apr 19 '17 at 1:03
  • \$\begingroup\$ Shouldn't hooking the data up to a 5v signal be equivalent to giving it data? My logic behind this is that if I wanted to light them all up I would give an entirely high signal and I'm guessing that's what hooking it up to a 5v power supply would do \$\endgroup\$ – Tyler H Apr 19 '17 at 1:08
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There is no test or all white function on the WS2812B leds. They require a specific timing signal on DIN (Data In) to show anything.

But simply hooking DIN to 5V should not damage them. Your description of a flash may be that they were damaged, or that you accidentally, by a fluke of timing, caused a level shift enough to make it think a real data signal came in.

You need a microcontroller with the appropriate code for the WS2812B protocol to see anything.

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These LEDs are supposed to require a data signal, which you need a microprocessor to generate. Connecting the data line to 5V or 0V will not give it a valid signal.

If you look at the WS2812B datasheet you will see that a 0 bit is a pulse with specific timing, and 1 bit is a pulse with different specific timing.

I have an APA102C strip, and while APA102C LEDs use an entirely different protocol from WS2812B LEDs, the general concept is the same. My strip will sometimes flash briefly when power is applied (I'm not sure if this is a feature to let me know it's connected, or the result of a glitch) but normally it does not light up at all until it's commanded to do so via the data signal.

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  • \$\begingroup\$ Ok that makes sense..... so I need an arduino or pi or something equivalent to light up the LEDS? Should I be able to find a library or something to do that for me? How would I go about finding that? Also do I need to attach the second red and black wires to anything (not the ones on the clip, but the 2 loose ones that I soldered header pins onto)? \$\endgroup\$ – Tyler H Apr 19 '17 at 1:21
  • \$\begingroup\$ The second wires are for an independent power supply. \$\endgroup\$ – Ignacio Vazquez-Abrams Apr 19 '17 at 1:22
  • \$\begingroup\$ @user2417339 googling "your microcontroller" "ws2812b" library. A RPi, or Arduino, or MSP430 Launchpad or any number controllers will work. \$\endgroup\$ – Passerby Apr 19 '17 at 1:22
  • \$\begingroup\$ @user2417339 as Ignacio said the second wires are just extra power connections. If you were chaining several strips together you'd join the connectors at the ends, and you'd also need to connect all the extra wires to a power supply, to avoid voltage drop problems. \$\endgroup\$ – immibis Apr 19 '17 at 1:31

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