skinny mini neopixel strips bad?

EL Wire/Tape/Panels, LEDs, pixels and strips, LCDs and TFTs, etc products from Adafruit

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mohawkpiper
 
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skinny mini neopixel strips bad?

Post by mohawkpiper »

Are the skinny mini neopixel strips more fragile compared to the regular neopixel strips?

I recently purchased a few strips of these and i have had already a few issues with some pixels on the 144/m strip in particular where a color in an LED goes out. Green died on one pixel and it seems as if Blue might be going out on another (although right at this moment it is working.)

I am assuming maybe heat is killing them.

A little info on what I am doing...

I have been making led mushroom lamps for a little while now and I embed the LEDs into polymorph plastic. I have been working with the regular thickness strips solely until now, I was trying to design some different shroom types that the skinny version of the neopixels greatly helped get them in there.

I noticed when soldering the skinny version strips they heated up a lot more than the regular strips.. i dont know what temp my soldering iron is at... it just has numbers like 1-5 and i use it at about 2 3/4.

I test every strip after soldering before embedding it in the plastic because removing the plastic later if i did a bad job is almost impossible.

So they all work after testing.. i embed them in plastic by melting the plastic in just below boiling water (low melt temp plastic) which should be about 200*F?

Again i've been doing this for a little while now and never had an issue with the regular thickness strips. But the skinny version i had one go bad once i got the plastic on.

Then just last night I was adding some plastic to one already finished mushroom that came out ok, and after heating up the cap of the mushroom and adding plastic another LED went bad. After letting that one cool completely it seems to be working again but I am concerned.

So far out of skinny 144, skinny 60, regular 144 and regular 60 the skinny 144 is the only one i am having issues with.

It kinda sux when that happens because I am not losing just 1 led out of the strip, depending on the mushroom i put it in i am loosing 4 to 12 leds.

in the pics you can see the green in the LED on the right of this shroom is not working.
Image Image Image Image

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adafruit_support_bill
 
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Re: skinny mini neopixel strips bad?

Post by adafruit_support_bill »

Haven't had any reports of problems with these. Mechanically, the narrower flex-backing would make it somewhat easier to over-flex and crack a solder joint. But if these are failing once they have been embedded in plastic, heat is the most likely problem.

Heat dissipation can be an issue - even with the regular width 144/meter strips. Embedding them in plastic does not help matters. Most plastics are not particularly good at conducting heat, so it has nowhere to go.

You will probably get longer lifetimes if you decrease the output level of the LEDs.

P. S. Nice looking lamps!

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mohawkpiper
 
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Re: skinny mini neopixel strips bad?

Post by mohawkpiper »

Okie dokie. I'll just do my best to be more careful with the heat... and thanks for the tip on the decreased output levels... i'll do that for this new one. I am noticing the larger cap shrooms and flat shrooms are a tad warm... (those ones have a lot of LEDs in them.) I didn't want to use the 144 strips because it's a lot of LEDs but with the 60 and anything else you can really see the spottyness of the LEDs which I didnt like.

I'll watch this new one for a while and see how it does.

The other ones with my first shroom type only have two LEDs per shroom... and they have been doing great for a month ish now?

Here are some full pics of the lamps...
Image Image Image

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adafruit_support_bill
 
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Re: skinny mini neopixel strips bad?

Post by adafruit_support_bill »

Yea, a smaller shroom has a higher ratio of surface area to mass for better heat dissipation. And with only 2 pixels supplying heat, they should run cooler.

Some of the casting resins have additives you can use to increase diffusion. But they are not quite as easy to use as the low-temp melting plastics.

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