Problem when cutting and resoldering NeoPixel strip

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Beno21
 
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Problem when cutting and resoldering NeoPixel strip

Post by Beno21 »

Hello !

I have recently purchased a 4-meter long NeoPixel strip (60 LEDs per meter). My goal is to cut "mini-strips" made of 3 LEDs and reconstitute the whole strip by soldering them together.
I tested the entire strip when I received it and it worked perfectly. Also, when I cut the first 3 LEDs with the connector without soldering anything they worked. But when I connect a second "mini-strip" at the end of the first one only the first mini-strip works... And after that I desoldered the connector and resoldered it in the same place and now nothing works...
I must say that I check that the connections are made in the right order, and I also checked the input/output direction of the strip.
One of my hypothesis is that maybe the soldering temperature I use is too high and damages the LEDs (350°C). Is it possible ?

Thank you in advance.

Benoit.

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adafruit_support_rick
 
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Re: Problem when cutting and resoldering NeoPixel strip

Post by adafruit_support_rick »

Please post clear pictures of your assembly and soldering

Beno21
 
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Joined: Mon Feb 03, 2014 4:31 pm

Re: Problem when cutting and resoldering NeoPixel strip

Post by Beno21 »

Here are the pictures ! The first one is the assembly I want to realize (with more "mini-strips", but I want to make it work with two at first :) ).
PIC_0152.JPG
PIC_0152.JPG (207.57 KiB) Viewed 310 times
The two other pictures are photographs of the connections:
connector to first strip:
PIC_0154.jpg
PIC_0154.jpg (257.19 KiB) Viewed 310 times
end of first strip:
PIC_0150.jpg
PIC_0150.jpg (212.75 KiB) Viewed 310 times

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adafruit_support_rick
 
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Re: Problem when cutting and resoldering NeoPixel strip

Post by adafruit_support_rick »

That should work. Use a multimeter to check the continuity of your connections. You may have a bad solder joint.

350ºC should not be too hot. In fact, it might be a little cold, if you're using lead-free solder.

Beno21
 
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Joined: Mon Feb 03, 2014 4:31 pm

Re: Problem when cutting and resoldering NeoPixel strip

Post by Beno21 »

I have already checked that, the contacts are all good...
I think I will try with a new section of the strip, maybe I broke some pixels without knowing...

Beno21
 
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Joined: Mon Feb 03, 2014 4:31 pm

Re: Problem when cutting and resoldering NeoPixel strip

Post by Beno21 »

Ok, that seems to be it...
I have replaced the "mini-strips" and now everything works correctly !
However I have one more question: since I connect my mini-strips with wires (whose length can change), do I need the 30ohms resistor just before each "mini-strip" ?

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adafruit_support_rick
 
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Re: Problem when cutting and resoldering NeoPixel strip

Post by adafruit_support_rick »

No, you should only need one resistor between the arduino and the first mini-strip.

Beno21
 
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Re: Problem when cutting and resoldering NeoPixel strip

Post by Beno21 »

Ok, everything works ! Thanks a lot for your useful advice !

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