WS2812B LED Strips
 
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WS2812B LED Strips

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(@russells)
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Joined: 3 years ago
Posts: 2
Topic starter  

Hi, firstly I just want to say how great SimHub is, I'm having great fun playing with Arduino's and LED dispalys etc.

Anyway, I am having an issue that I'm hoping someone can help with.

I am using 3 cascaded WS2812B boards with 8 LED's on each board.  The first two boards are directly cascaded (butted up to each other) to give a continuous strip of 16LED's and then the third board is cascaded off of this but instead of butted up it is at the end of 150mm wires.

The first strip of 16 LED's work fine but I cannot get the ones at the end of the wires to work. I can get all 8 LED's to light up RED but that's about it. If I select BLUE they won't light up at all and if I select YELLOW they light up RED again. In the LED editor if I setup the RPMS to cover all 24 LED's then the first 16 are fine but then the last 8 (on the offending strip) barely light up at all.

I have replaced the offending strip but had the same result and I have replaced the wiring again with no change. If I wire up the offending strip on it's own it works absolutely fine so I know it's not a problem with that.

So I was just wondering if by having the last strip at the end of 150mm wires does it upset the cascade process and do the strips have to be directly butted up to each other to work correctly.

 

Any advice greatly welcome. Thanks


   
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(@admin5435)
Prominent Member Admin
Joined: 7 years ago
Posts: 727
 

Hi ! in theory long wiring is not a big issue, but it looks like data can't flow correctly in your case,
it would be worth re-injecting 5v+gnd straight at the beginning the last strip instead of making go through the first modules to see if it helps.


   
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(@russells)
New Member
Joined: 3 years ago
Posts: 2
Topic starter  

Thanks for that suggestion but it still doesn't work.

I just don't understand this at all. So as you suggested I connected the 5v & GND directly to both the first module and the third module with no change. I also as a test did away with the wires to the third module and connected it directly butted up to the end of the second module to make a continuous 24 LED strip and still the first 16 LED's work fine but the last 8 would not.

Also, just in case it was a power issue, I used an external power supply for the 5v instead of connecting to the Arduino Nano and still it is the same. In desperation I have even swapped to an Arduino Uno just to eliminate the Nano as being the problem but the third module still doesn't work correctly.

As another test I've connected a flexible strip of 144 WS2812B LED's and that works fine. Maybe a little excessive having a 1m long rev bar though.

So in conclusion I think I just have rubbish LED modules. I will order some more from another source and see if they work better.


   
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