Strange thing displ...
 

Strange thing displaying active ABS and TC on WS2812B  

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Sigma7
(@sigma7)
Active Member
Joined: 1 month ago
Posts: 6
10/09/2019 8:07 pm  

Dear ladies and gentlemen,

i noticed some strange behaviour using WS2812B leds in combination with active ABS and TC in Assetto Corsa Competizione. I soldered 10 led-chips together as shiftlights and other stuff like yellow flags (this ones: https://www.amazon.de/gp/product/B01DC0J0WS/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1). So everything works fine except abs and tc. Expample: when i show an active abs on led number 3 for example it flickers or light up constantly during braking, so no problem, works as it should. But very often another led in the chain after the 3rd led flickers or light up in the same colour as the original configured abs-led. The same happens with tc.

Is that a problem of the controller chip in the led? it is like the chip is transferring data to another led, but its not configured in the led-screen.

Edit: i use it with an Arduino Nano V3 clone.

 

Thanks,

cheers,

Sigma7

This topic was modified 1 week ago 2 times by Sigma7

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Wotever
(@admin5435)
Member Admin
Joined: 2 years ago
Posts: 25
10/09/2019 8:35 pm  

Hi ! This clearly looks like LEDs going out of sync, usually this comes from soldering quality issues. 

It's also possible but it's more rare that one or more LEDs are defective or bad quality. This is more tedious to detect as it often act at high refresh frequency (like showing TC or abs "ultrafast" changing values) and any test sketch are often slower and won't "reveal" the issue.

So at a first step I would check first the soldering as it's the most common issue.

Also try to change the usb cable, or anything which could transport parasites (usb cable, hub ....)


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Sigma7
(@sigma7)
Active Member
Joined: 1 month ago
Posts: 6
10/09/2019 8:49 pm  

@admin5435

Hey Wotever. Thank you for your reply. I will check the cable and soldering.


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Sigma7
(@sigma7)
Active Member
Joined: 1 month ago
Posts: 6
11/09/2019 12:17 pm  

Hi, i have not had time yet to check the soldering. But i like to talk about this because i really don't get the technical context between bad solder joints and this kind of behaviour. Thus far i thought cold or respectively bad solder joints appear as there is no connection and therefore no power transfer. The behaviour that sometimes it works and suddenly this anomaly happens is new to me.

You think the problem is in the data line soldering joints or could the joints on the gnd and 5v power also be the problem? And further could this be a problem with the power supply itself. In my case the arduino gets the power from an usb 3.0 usb-hub. Do you think an external power supply could fix the problem? Has the thickness of the connecting wire any effect? I used 0.8 millimeter tinned copper wire.

Anyway, i will check your hints (cable, hub etc.)

Cheers!

This post was modified 1 week ago 2 times by Sigma7

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Wotever
(@admin5435)
Member Admin
Joined: 2 years ago
Posts: 25
11/09/2019 10:09 pm  

@sigma7

Actually the data goes very fast on the wire so any "parasites" will randomly break the transmission and cause display issues. That's why like an usb cable chewed by a dog will randomly work, here it will be the same : with a bad connection, it will randomly work and alter the data sent to the leds. It can be direct : the data line being unstable or undirect: power or GND creating parasites like micro voltage drops or data loss. Powering can be an issue too (voltage drops) moreover with usb hubs, to test it simply connect it directly to your pc and bypass any hub, they are indeed a big source of issues. 


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Sigma7
(@sigma7)
Active Member
Joined: 1 month ago
Posts: 6
13/09/2019 2:18 pm  

Okay, a little update on this thing here. I tried different usb ports at the computer itself and different usb cables with no luck. Using an external 5v power supply didn't make any difference too. Same result. So i decided to do some tests with PL9823 5mm LEDs on a breadboard. In this test, the strange behaviour was NOT present. If i am correct, the PL9823 has the same controller as the WS2812B LED-chips. As a result the problem must be the soldering or faulty LED-chips i don't know. Maybe i will solder another 10 of these chips together and test again.

This post was modified 1 week ago 2 times by Sigma7

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Sigma7
(@sigma7)
Active Member
Joined: 1 month ago
Posts: 6
13/09/2019 4:21 pm  

I soldered 2 leds together with small wires. The same problem. I can't really believe i am that bad in soldering ^^. I have to test it again with soldered PL9823.


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