WS2812B LED's

[Yorkie]

I purchased 10 WS2812B LED’s from Ebay but after wiring them all up I found that only the first one in the line will light – any ideas?

[winkleink]

Would need to see circuit and code as well as link to eBay product.
Could be any of these.

[Yorkie]

The Ebay item is:

http://www.ebay.co.uk/itm/10-x-WS2812B-LED-5V-RGB-LED-Pixel-WS2812-Built-in-control-Arduino-Rpi-Neo-pixel-/321930993806?

The wiring was just a ‘daisy chain, D to Din, Dout to Din etc, plus the 5V & 0V connect to + & – on the Crumble.

I could control the first LED but none of the others – sorry I can’t screen shot the code but it was just “Set sparkle 0 to red, wait 1 second, set sparkle 1 to red, wait 1 second”, all inside a ‘Do Forever Loop’

[Joseph]

Hi Yorkie,

From your description, the wiring sounds ok. It could be a faulty 2nd LED, which is preventing data from propagating. Could you try connecting the Crumble to different LEDs on the chain?

Best wishes,

Joseph

[Yorkie]

Yes I tried that.

[Joseph]

Mmmm. If only one of the LEDs works when connected to the Crumble (i.e. if you try to connect all of them as the first LED), then it sounds like the other WS2812Bs may be faulty. If you remove the wiring you’ve added and connect each one in turn, you could be fairly sure if the LEDs are good.

It’s also worth noting that the WS2812Bs no longer seem to have reverse polarity protection (they’ll pop if the polarity is reversed). The Sparkles have an additional protection diode to prevent this.

Hope this helps,

Joseph

[Author]

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