WS2811 RGB strip lights up in groups of three

[mfalkvidd]

I have bought a 5m "30 IP20 Whitre PCB" led strip, http://www.aliexpress.com/item/WS2811-led-strip-5m-30-48-60-leds-m-IP30-65-67-10-16-20-pcs/32658513954.html

When I light them, they always light up in groups of three. So they are addressable, but not individually. If I light up only the first pixel, the first three pixels light up (in the same color). If I light up 12 pixels, 36 pixels light up. If I light the first pixel green, second red, I get three green followed by three red.

I get the same behavior NeoPixels and FastLED.

Have I gotten a crap delivery? Or am I doing something wrong?

Since the strip is 12V, it probably has three leds in series, right? So any 12V strip is likely to only be addressable in groups of 3?

[Daniel Oliveira]

Hi,

Looking at the product picture indeed there is only one WS2811 IC per each 3 LEDs. So... I'm afraid the behaviour that you describe is that LED strip can do...

I have around here some WS2801 LED strips and there's one IC per LED.

[Daniel Oliveira]

Just found this in the product description : "LED Type: 1 WS2811 IC control 3 LED Chip,"

[mfalkvidd]

Thanks @Daniel-Oliveira. I read the part about 3 leds but thought that one IC controlled three leds individually. But since WS2811 can only control one address per chip, it makes sense that they light up in groups of 3.

Oh well, you always learn something :)

[Daniel Oliveira]

Well... I'm sorry for you, but at least now everyone that reads this thread will be aware.

Cheers

[mfalkvidd]

@Daniel-Oliveira yup. For me, electronics is all about learning new stuff. Either from other people's mistakes, or by my own mistakes :)

Thanks for the quick answer.

[Tetnobic]

@mfalkvidd So where you buy the right led strip ?
Thanks for your reponse

[mfalkvidd]

@Tetnobic https://www.aliexpress.com/item/1m-2m-3m-4m-5m-ws2812b-ws2812-led-strip-individually-addressable-smart-led-strip-black-white/32682015405.html
I bought 5m 30 black pcb ip30

[Nicklas Starkel]

@mfalkvidd , quite OT, but how do you power these?
I have them as well and when I calculate how much amp they should draw it is quite much!
However, when I check what they actually draw is quite low. Around 3-4A on full bright white.
Do not really know what I should aim for because you can find nice 5A or less quite easily while above this you would have to go with big ugly power supplys.
And it's a shame they work in 5V only as 12V would be much better for me (and get more A out of as well from smaller power supplys)

[mfalkvidd]

@Nicklas-Starkel yep, that is a problem, at least in theory.
However, I have been powering my arcade game screen from a 2.1A USB powerpack without problems. So maybe they don't use as much power as they are specified for.

I am considering buying a good 230VAC->12VDC adapter and use one or a few of these to get 5V: https://www.aliexpress.com/item/5A-XL4015-DC-DC-4-38V-to-1-25-36V-24V-12V-9V-5V-Step-Down/32713638689.html

If you find anything nice, please let me know.

[jack.historia]

You guys had the wrong LED type in the arduino setup:

//   NEO_GRB     Pixels are wired for GRB bitstream (most NeoPixel products)
//   NEO_RGB     Pixels are wired for RGB bitstream (v1 FLORA pixels, not v2)
//   NEO_RGBW    Pixels are wired for RGBW bitstream (NeoPixel RGBW products)

I have the 12V GRB option - one controller connected to 3 leds but it runs smooth as a cat. With RGB and RGBW it doesn't work that well and I see only 3 led chunks. ali express link 12V2811 5m |1 50 leds | White PCB

That is the setup line that works for the WS2811 RGB strip (GRB strip):

Adafruit_NeoPixel strip = Adafruit_NeoPixel(NUM_LEDS, PIN, NEO_GRB + NEO_KHZ800);

I went on this by accident and I thought I should let you know even after 2 years :-) Hope that helps