Increasing NeoPixel separation

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kadamr
 
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Increasing NeoPixel separation

Post by kadamr »

I have a few hundred NeoPixel LEDs in 60/m strips. I've connected them up and have everything working fine. Now I want to fix them to a physical matrix with each pixel separated by 2 inches (more than the strip separation currently). This wouldn't be a problem ordinarily, but I need to maintain a strip-like structure with very low profile (except the LEDs themselves sticking out). Regular wires are too high profile for my application. I would prefer to use something like copper tape to join up the three lines (power and data) between the LEDs after cutting them up. Is cutting them apart going to cause any issues? And can I use copper tape and resolder them at 2 inch separation on a new backing tape or will the tape not carry enough current or overheat? It would need to be pretty thin copper tape in height and width. Are there any other issues I might face or a better option? I have 12 lengths of 24 LEDs, I can connect every strip end to a new power line if that reduces current through the whole strip. Thanks!

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adafruit_support_bill
 
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Re: Increasing NeoPixel separation

Post by adafruit_support_bill »

Sounds like a lot of work. You might find it easier to start with the raw chips: https://www.adafruit.com/products/1655
In any case, it should be possible. Feeding power to every row should limit losses due to the strip resistance.

kadamr
 
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Re: Increasing NeoPixel separation

Post by kadamr »

adafruit_support_bill wrote:Sounds like a lot of work. You might find it easier to start with the raw chips: https://www.adafruit.com/products/1655
In any case, it should be possible. Feeding power to every row should limit losses due to the strip resistance.
I've bought these because I have so many it was significantly more cost effective. I was planning to put three long copper lines down and then place the cut out NeoPixels on top of the lines and solder each of the three pads on each side. Would I have to cut the copper tape under the LEDs or they would effectively be connected in parallel, or is that okay...?

This was the tape I was thinking of using. At 6 mm it's too wide. Looks like I would need about 1 mm thickness to match each of the three pads on the NeoPixels - I couldn't find tape that thin, do you know if it exists? I don't know how to calculate if that will cause any issues for a 24 LED length strip at only 1 mm width. I don't want it melting or anything! Is there any alternative way of making low-profile traces? Thanks for your help!

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adafruit_support_bill
 
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Re: Increasing NeoPixel separation

Post by adafruit_support_bill »

I was planning to put three long copper lines down and then place the cut out NeoPixels on top of the lines and solder each of the three pads on each side. Would I have to cut the copper tape under the LEDs or they would effectively be connected in parallel, or is that okay...?
The power and ground lines can be continuous, but the signal line needs to go from pixel to pixel.
Looks like I would need about 1 mm thickness to match each of the three pads on the NeoPixels - I couldn't find tape that thin, do you know if it exists?
The narrowest copper tape I have seen is 5mm. I have seen listings from manufacturers for narrower widths, but the minimum quantities would be a killer. The power and ground runs are on the outside, so they could be a little wider (that would be better for power handling anyhow). The signal line doesn't carry much current, so it can be as fine as you like. You could make signal connections with ultra-thin wire like this: https://www.adafruit.com/product/1446

kadamr
 
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Re: Increasing NeoPixel separation

Post by kadamr »

The signal line doesn't carry much current, so it can be as fine as you like. You could make signal connections with ultra-thin wire like this: https://www.adafruit.com/product/1446[/quote]

Thanks for the advice, I'll give it a try. Out of curiosity, if I were to use wire for the power lines as well then what diameter would you suggest - something like 22 AWG? I'll have to use wire at the ends of the tape eventually. I wanted to use something like the 4-pin JST SM connectors you sell, but there don't seem to be 3-pin versions?

Oh, and is the copper tape easy to cut? I could use a paper guillotine to cut along it's length to make it 1 or 2 mm wide, unless it's very tough?

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adafruit_support_bill
 
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Re: Increasing NeoPixel separation

Post by adafruit_support_bill »

if I were to use wire for the power lines as well then what diameter would you suggest - something like 22 AWG?
That would probably be OK. But if you will be driving them hard (lots of pixels on at once) you should consider powering each strip from both ends.
Oh, and is the copper tape easy to cut?
It cuts easily with scissors.

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