Does this product (#1612, http://www.adafruit.com/product/1612) use the WS2812B variant?
Those look pretty cool. I may have to order some, darn it!
NeoPixel Strip with Dead NeoPixels
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Please be positive and constructive with your questions and comments.
- adafruit_support_bill
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Re: NeoPixel Strip with Dead NeoPixels
Yes. It uses the WS2812B.
-
- Posts: 7
- Joined: Mon Jun 13, 2011 10:06 am
Re: NeoPixel Strip with Dead NeoPixels
Hello all,
same happened to me TWICE last week: two dead Neopixel Stripes with 144 RGBs (!)
I thought I've done everything right: Lab-power supply, resistor in the data line, and a 1000µF condensor
and I'm still killing my Neopixels: First WS2812B is dead.
I'm not sure whether just one big capacitor is enough:
Big capacitors handles low frequency ripple and mains noise and major output load changes.
Small capacitors handle noise and fast transients
I assume that the problem is the fast transients - what means a big and a small cap should be connected in parallel.
Maybe a Zener diode would be also useful.
Adafruit, could you please investigate this and come up with the component suggestions? Maybe you can add an already built circuit board to your store.
Thanks a million !
Juergen
same happened to me TWICE last week: two dead Neopixel Stripes with 144 RGBs (!)
I thought I've done everything right: Lab-power supply, resistor in the data line, and a 1000µF condensor
and I'm still killing my Neopixels: First WS2812B is dead.
I'm not sure whether just one big capacitor is enough:
Big capacitors handles low frequency ripple and mains noise and major output load changes.
Small capacitors handle noise and fast transients
I assume that the problem is the fast transients - what means a big and a small cap should be connected in parallel.
Maybe a Zener diode would be also useful.
Adafruit, could you please investigate this and come up with the component suggestions? Maybe you can add an already built circuit board to your store.
Thanks a million !
Juergen
- adafruit_support_bill
- Posts: 88088
- Joined: Sat Feb 07, 2009 10:11 am
Re: NeoPixel Strip with Dead NeoPixels
Hi Juergen, Can you tell us a bit more about your system? A photo would be helpful too.
What processor are you using to control the Neopixels? What is the distance between the processor and the first pixel? What other components are in your system?
We do keep our Best Practices page up-to-date, and will update it with new information as we get it. http://learn.adafruit.com/adafruit-neop ... -practices
What processor are you using to control the Neopixels? What is the distance between the processor and the first pixel? What other components are in your system?
We do keep our Best Practices page up-to-date, and will update it with new information as we get it. http://learn.adafruit.com/adafruit-neop ... -practices
-
- Posts: 7
- Joined: Mon Jun 13, 2011 10:06 am
Re: NeoPixel Strip with Dead NeoPixels
my system looks like this:
Arduino Mega 2560, USB-powered, signal cable lenght 2 ft, dia 0.25mm², resistor already in stripe; power cable 0.50mm², 1 ft, Lab power supply 5.03V (20A); 1000µF 50V cap.
The stripe is normally fully inserted in the aluminum profile.
Here I have 'injected' the signal line right after the first LED
Works ! - means I have blown the first LED
Q: does the first WS2812 blow because of a surge on the signal line (Arduino is powered off my PC) or because of a voltage spike?
If voltage spike: why only the first LED ??
Observation: both times the stripes froze while running the sample sketch.
When disconnected they did not light up anymore.
Hope that helps
Juergen
Arduino Mega 2560, USB-powered, signal cable lenght 2 ft, dia 0.25mm², resistor already in stripe; power cable 0.50mm², 1 ft, Lab power supply 5.03V (20A); 1000µF 50V cap.
The stripe is normally fully inserted in the aluminum profile.
Here I have 'injected' the signal line right after the first LED
Works ! - means I have blown the first LED
Q: does the first WS2812 blow because of a surge on the signal line (Arduino is powered off my PC) or because of a voltage spike?
If voltage spike: why only the first LED ??
Observation: both times the stripes froze while running the sample sketch.
When disconnected they did not light up anymore.
Hope that helps
Juergen
-
- Posts: 7
- Joined: Mon Jun 13, 2011 10:06 am
Re: NeoPixel Strip with Dead NeoPixels
Here is a suggestion how a voltage swing suppression could look like
(Thanks to Andrew from Toastedcircuits.com)
Would this work?
(Thanks to Andrew from Toastedcircuits.com)
Would this work?
- adafruit_support_bill
- Posts: 88088
- Joined: Sat Feb 07, 2009 10:11 am
Re: NeoPixel Strip with Dead NeoPixels
We are not entirely sure. We have not been able to reliably reproduce the problem here. Some users have reported success using the capacitor on the power supply. Others have reported success using the resistor on the signal line, so at this time we are recommending both. The cautions about making connections before power-up and connecting the ground first are just good practice overall.Q: does the first WS2812 blow because of a surge on the signal line (Arduino is powered off my PC) or because of a voltage spike?
If voltage spike: why only the first LED ??
That is an interesting data point. Most users have reported that the problem occurs at startup or when re-connecting. I have not heard of issues with freezing while running.Observation: both times the stripes froze while running the sample sketch.
When disconnected they did not light up anymore.
I think it is worth testing. If you could give that circuit a try (injecting the signal into the second pixel) and let us know how it works for you. I will forward your observations to the rest of the engineering team and see if we can identify the root cause of the problem.Here is a suggestion how a voltage swing suppression could look like
(Thanks to Andrew from Toastedcircuits.com)
Would this work?
Thank you for your cooperation in this matter
-
- Posts: 7
- Joined: Mon Jun 13, 2011 10:06 am
Re: NeoPixel Strip with Dead NeoPixels
What confuses me is that if it is a voltage problem I'd expect all LEDs to blow out. If only the first LED is dead it points towards a problem with the data line.
That would explain why the series resistor in the data line helps other users.
Do you have information on the capacitance of the WS2812 ?
Andrew suggests three possible approaches:
a) A fast-response diode from the data lines to ground, reversed. This will ensure that if the data line wants to go below zero (i.e. the GND line rises due to current issues) it can't fall too far.
b) A low value series resistor and then a zener (in parallel -- i.e. to ground) on the data and clock inputs.
c) A voltage divider to drop the data line voltage to about 3.5v...
Could you please discuss these solutions?
Thanks a million !
That would explain why the series resistor in the data line helps other users.
Do you have information on the capacitance of the WS2812 ?
Andrew suggests three possible approaches:
a) A fast-response diode from the data lines to ground, reversed. This will ensure that if the data line wants to go below zero (i.e. the GND line rises due to current issues) it can't fall too far.
b) A low value series resistor and then a zener (in parallel -- i.e. to ground) on the data and clock inputs.
c) A voltage divider to drop the data line voltage to about 3.5v...
Could you please discuss these solutions?
Thanks a million !
- adafruit_support_bill
- Posts: 88088
- Joined: Sat Feb 07, 2009 10:11 am
Re: NeoPixel Strip with Dead NeoPixels
Thanks for the input. I'll review these with the team
- Kramy
- Posts: 1
- Joined: Sun Jul 30, 2017 5:17 am
Re: NeoPixel Strip with Dead NeoPixels
Sorry to be a thread BANNED, but was there a verdict on what to wire in and how?
I got an RGB LED strip, turned it on and ran a sketch... had some neat colours happening, and then the first LED turned off. It wouldn't come on again until I left it off for a while. Now it's alive again, but I don't want to risk killing it, so I'm looking into what parts I need to wire in before it to keep it going.
I got an RGB LED strip, turned it on and ran a sketch... had some neat colours happening, and then the first LED turned off. It wouldn't come on again until I left it off for a while. Now it's alive again, but I don't want to risk killing it, so I'm looking into what parts I need to wire in before it to keep it going.
- adafruit_support_bill
- Posts: 88088
- Joined: Sat Feb 07, 2009 10:11 am
Re: NeoPixel Strip with Dead NeoPixels
Our current recommendations are in the Best Practices page: http://learn.adafruit.com/adafruit-neop ... -practices
The capacitor is strongly recommended when powering with a plug-in power supply to suppress any start-up spikes.
The resistor is recommended when there is a long run (substantially more than 8") between the processor and the first pixel.
Note that the resistor needs to be mounted as close to the first pixel as possible. Many people put it on the processor end, or somewhere in the middle where it doesn't do any good.
The capacitor is strongly recommended when powering with a plug-in power supply to suppress any start-up spikes.
The resistor is recommended when there is a long run (substantially more than 8") between the processor and the first pixel.
Note that the resistor needs to be mounted as close to the first pixel as possible. Many people put it on the processor end, or somewhere in the middle where it doesn't do any good.
Please be positive and constructive with your questions and comments.