NeoPixel Strip 60 LED burned first pixel problem

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ispyab
 
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NeoPixel Strip 60 LED burned first pixel problem

Post by ispyab »

Hi,

We are working on a project where we are going to use 7 x 1m NeoPixel strips (60 led per meter) connected to a Flora. However we are having huge problems with the stips bought from Adafruit last week. We solder everything up, everything works great, then randomly it stops working. Cutting the first pixel out has fixed the problem two times however every time we cut the first pixel, we also need to cut a pixel of the other strips.

This is how its all hooked up:
Overview of the connections
IMG_2672.jpg
IMG_2672.jpg (270.79 KiB) Viewed 2665 times
Close up at power side
IMG_2674.jpg
IMG_2674.jpg (318.86 KiB) Viewed 2665 times
Close up of other side
IMG_2673.jpg
IMG_2673.jpg (301.05 KiB) Viewed 2665 times
We are currently powering everything with 3 AAA batteries (4.5V) and are only running code that lights up a couple of LED:s at a time to test that all pixels work as they should. As mentioned above it all works for a while, and then the first pixel dies. When it stops working we have tried to jumper over the dead pixel, but we have never succeeded to get it to work without cutting the pixel out.

The battery holder that we use (included in a Flora start pack) always has the power switch OFF when connecting or disconnecting, and we use a 330Ω resistor on the data line.

Any suggestions?

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adafruit_support_bill
 
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Re: NeoPixel Strip 60 LED burned first pixel problem

Post by adafruit_support_bill »

Read through the "Best Practices" page of the Neopixel Guide: http://learn.adafruit.com/adafruit-neop ... -practices

The resistor on your signal wire should be at the neopixel end, not at the Flora end of the wire. And connections should be soldered.

Battery power is usually pretty clean so the capacitor probably won't help much. But do observe the cautions regarding making connections and guarding against static discharges.

ispyab
 
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Re: NeoPixel Strip 60 LED burned first pixel problem

Post by ispyab »

Thanks for your answer, we have read the guide however missed the part where the resistor should be on the neopixel side. Our strips did have resistors at the first pixel from the beginning, but we had to cut that pixel out because it died, so I guess it didn't help that much.
Is there any way to jumper over a dead first pixel without cutting it out? We have tried to connect a jumper from Data IN on the first pixel to the Data IN on the Next one, but it never works.

Also we handle all the strips with antistatic wrist strap to minimize ESD and our soldering station is ESD-safe.

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adafruit_support_bill
 
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Re: NeoPixel Strip 60 LED burned first pixel problem

Post by adafruit_support_bill »

We have tried to connect a jumper from Data IN on the first pixel to the Data IN on the Next one, but it never works.
Have you tried just moving the wire to DIN on the second pixel? That usually works.

Do the failures occur at startup, or during operation of the pixels?

ispyab
 
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Re: NeoPixel Strip 60 LED burned first pixel problem

Post by ispyab »

Moving the signal from the Flora to DIN on the second pixel does not work (or any other pixel in the chain) The only way to make it work again is to cut out the first pixel.

The failure is at startup. When it has failed it simply does not start up (no blinking or other signs of life). It has never failed when operating. We also have a 8x8 NeoPixel matrix that works perfectly every time we connect it to the same Flora with the same battery-holder and resistor.

Very strange...

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adafruit_support_bill
 
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Re: NeoPixel Strip 60 LED burned first pixel problem

Post by adafruit_support_bill »

The failure is at startup.
I'd try adding the capacitor then.
We also have a 8x8 NeoPixel matrix that works perfectly every time we connect it to the same Flora with the same battery-holder and resistor.
That's an interesting data point. The matrix does use a slightly different variant of the chip. I'll run this by our neopixel experts.

ispyab
 
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Re: NeoPixel Strip 60 LED burned first pixel problem

Post by ispyab »

Thanks!

1chicagodave
 
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Re: NeoPixel Strip 60 LED burned first pixel problem

Post by 1chicagodave »

We are working on a project where we are going to use 7 x 1m NeoPixel strips (60 led per meter) connected to a Flora.....
.....We are currently powering everything with 3 AAA batteries (4.5V) and are only running code that lights up a couple of LED:s at a time...
7 strips x 60 NeoPixels/strip == 420 NeoPixels

My 1 meter 30 Neo Pixel strip consumes 32 mA of current with all pixels 'off' and data line disconnected. That's about 1mA/NeoPixel just sitting there without any data being sent.

IF that number is consistent in greater multiples, there is a chance that your setup requires at least 400mA. I'm not sure what the current limits of your AAA batteries are....but that may be a factor here?

ispyab
 
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Re: NeoPixel Strip 60 LED burned first pixel problem

Post by ispyab »

Hi and thanks for your suggestion.
We know that the power source is a small, but we have been running all strips with 3 AAA batteries and also turning a lot of pixels on without problems, even with old batteries. When it all dies we cannot get it to work with fresh batteries. However we are going to replace the power source as soon as we can get the strips working reliably.

I have been looking at the 8x8 panel and the single Flora RGB pixels that we have been running and noticed that it uses a different led chip with 6 pins. The strips uses a chip with 4 pins. Is the chip with 4 pins more sensitive than the ones with 6 pins? My thought was to cut the first pixel in the strip and replacing it with a Flora RGB pixel to see if that works better.

ispyab
 
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Re: NeoPixel Strip 60 LED burned first pixel problem

Post by ispyab »

So we cut the first pixel out and replaced it with a Flora RGB pixel (with 330 ohm resistor on input). Only the first pixel works.

We are about to loose our client because of this, so we will be ordering new strips because we don't have the time to trying to find out why our strips is constantly failing and we honestly can not deliver a product to our client that we cannot trust. Looking at images the white strips use the 6 pin LED chip. Are you having the same problems with this strip or is it isolated to the black strips with 4 pin LED chips?

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adafruit_support_bill
 
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Re: NeoPixel Strip 60 LED burned first pixel problem

Post by adafruit_support_bill »

Looking at images the white strips use the 6 pin LED chip. Are you having the same problems with this strip or is it isolated to the black strips with 4 pin LED chips?
Looks like the black strips are using the "B" version of the chip while the white strips are still using the "A" version. Looking back over the issues reported, I do see that some have had trouble driving the black strips from 3.3v processors (of which the Flora is one). One solution is to buffer the signal with a 74HCT245 chip. Strips based on the "A" chip (such as the white ones) work fine with 3.3v signals. We have not correlated strip color with any dead-pixel problems.

If you contact [email protected] with a link to this thread we can try replacing the black strips with white ones. Please observe all the Best Practices when wiring these up.

[Edit - The A type strips are no longer available]

ispyab
 
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Re: NeoPixel Strip 60 LED burned first pixel problem

Post by ispyab »

adafruit_support_bill wrote:
Looking at images the white strips use the 6 pin LED chip. Are you having the same problems with this strip or is it isolated to the black strips with 4 pin LED chips?
Looks like the black strips are using the "B" version of the chip while the white strips are still using the "A" version. Looking back over the issues reported, I do see that some have had trouble driving the black strips from 3.3v processors (of which the Flora is one). One solution is to buffer the signal with a 74HCT245 chip. Strips based on the "A" chip (such as the white ones) work fine with 3.3v signals. We have not correlated strip color with any dead-pixel problems.

If you contact [email protected] with a link to this thread we can try replacing the black strips with white ones. Please observe all the Best Practices when wiring these up.
Thanks!

ispyab
 
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Re: NeoPixel Strip 60 LED burned first pixel problem

Post by ispyab »

We have now confirmed with the support that there are no strips left with the 6-pin LED version. All strips are the newer ones. Could you please advice how we can get these to work with the Flora without breaking? We are handling all strips according to the best practices guide and are feeding them with 4.5V battery power so they should be working without problems.

I must say that we are very disappointed whit this....

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adafruit_support_bill
 
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Re: NeoPixel Strip 60 LED burned first pixel problem

Post by adafruit_support_bill »

You can try the 74HCT245 buffer chip described in this post: http://forums.adafruit.com/viewtopic.php?f=47&t=48908
Another possibility is to lower the supply voltage. The newer chips appear to prefer a signal level much closer to the supply level. My experience with 3.7v LiPos has been good.

I will consult with our neopixel experts to see if they have any further advice.

ispyab
 
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Re: NeoPixel Strip 60 LED burned first pixel problem

Post by ispyab »

Thanks Bill, we will try that and cross our fingers that it works! :)

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