This was my first (and possibly last) attempt at making a matrix out of

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(Jason Coon) #1

This was my first (and possibly last) attempt at making a matrix out of strips. :slight_smile: I very strongly dislike soldering LED strips, especially the 144 per meter ones I used for this project. Any pointers? I soldered straight break away headers to each end, but had to sacrifice one LED per strip so I had a full pad on each end.

Aside from that, this was a pretty easy build. There are build notes in the pictures, if you’d like more details.

This was a fairly quick prototype build, I hope to rebuild it, and maybe bring the LEDs closer to the shade for a little less diffusion.

Any suggestions from you build pros out there?

Originally shared by Jason Coon

More video and pics, and a peek inside my latest prototype lamp. Source code and more details: https://github.com/jasoncoon/ParticleCoreMatrixLamp

(JP Roy) #2

Hey Jason, this is a very nice assembly !
I will be honest… I have never bought a strip of LEDs in my life !!!

I just bulk purchased ws2812b on mini boards and
another bulk purchase of the 8mm RGB LEDs with ws2811
a while back and have managed to do all my projects
so far with only these 2 package styles. So that was
a lot of soldering but never to strips and I still
have a bunch leftover to do more stuff!

If you dislike soldering to strips that much the only option that comes to my mind (apart from using discrete components like I do…) is to have PCBs made!!

There is of course a higher cost to this alternative compared to using strips and cutting them down to size but there would be significant advantages also…

  1. That PCB can have the shape YOU want, not just straight
  2. You can place mounting holes where you want on that PCB that aligns with the location you are going to mount it.
  3. It is more robust than strips.
  4. You can add a number of other components if that is useful.

OK I stop here, you get the picture…

(Jason Coon) #3

Thanks, JP! That means a lot to me, especially coming from you. Your builds are fantastic and very inspiring!

Yeah, I have to be honest, soldering individual LED boards sounds even less appealing to me than strips. :slight_smile:

I thought about learning to design custom PCBs, and having OSH Park or somewhere make them for me. That’s probably the next step in my electronics journey anyway. I tire of breadboards and perfboard. :slight_smile:

(JP Roy) #4

Just had a thought about re-doing that lamp with LEDs closer to the diffuser as you mentioned…

Why not just spiral a long flexible strip on a wide cone or cylinder shape ?

(Marc Miller) #5

That’s pretty cool Jason. Nice build. I like the header pin idea.

(Jason Coon) #6

Good idea, JP, might have to try it and then figure out how to map it to a grid. The pipe I’m using now was likely too small to wrap around without damaging the strip.

(Jason Coon) #7

Thanks, Marc. I’m not sure the headers were worth the trouble. I might try it without them and compare.

(JP Roy) #8

@Jason_Coon Unless you use a cylindrical shape and make sure that the circumference matches your pixels spacing on the strip such that the pixels align vertically, you will get an irregular grid matrix from that long spiralled strip! it. Would be a (not impossible) challenge to make that work.

(Marc Miller) #9

@Jason_Coon ​ So were they maybe harder to solder then wires? The pin spacing lines up perfectly though (at least on my APA102C strip).
Having to sacrifice a pixel at each cut is indeed a bit of a bummer.

(Mike Thornbury) #10

This might be less painful: http://www.aliexpress.com/item/Free-Shipping-RGB-LED-Strip-Connector-LED-Connector-For-RGB-LED-Strip-5050-3528-LED-Light/1421626588.html?spm=2114.32010308.4.11.Vbl81c

Nice job, though.

(Mike Thornbury) #11

@Jason_Coon , if you want a hand with custom PCBs, give me a shout, I have APA, WS28xx libraries, etc. I have just made a lamp PCB, but with a heck of a lot less LEDs than you used. :slight_smile:

(Jason Coon) #12

Thanks, Mike, I might have to take you up on your offer. :slight_smile: I’ve never done any PCB design, or used Eagle or KiCad, but hope to try soon.

I’ve looked at those connectors before, but I’m not sure they’d work with the 144 per meter strips. There’s just not much space between them, and the pads are tiny. I might have to use the 72 per meter strips next time, might be much easier.

(Reed Morse) #13

Here’s a tip for soldering LED strips:

First prime the strips by tinning each pad. Hold your iron against the pad for 5-10 seconds so it heats up, then melt some solder to the pad. If it isn’t sticking well, you need more heat.

After the strips are primed like this, solder your wires on.

(Mike Thornbury) #14

And use flux.

(Stefan Petrick) #15

" Good idea, JP, might have to try it and then figure out how to map it to a grid."

It’s very simple - just handle it as a non-zigzag matrix. Unless you are going to display GIFs it doesn’t matter that the vertical line might become a diagonal one - it will look cool anyway. Here in my first “spiral matrix” the vertical line basically describes a 360 degree turn from top to bottom. https://www.youtube.com/watch?v=4qiDcKd8xO0 Do you see it, could you tell that the mapping is twisted? (P.S. I avoid soldering strips too, whenever it’s possible…)

(Stefan Petrick) #16

Also: A 144/m strip I coiled successfully arround a german toilet paper roll (arround 5 cm diameter). It was meant to be a destruction test but it worked (and still works) fine. The hardest part was to dare to just do it.

(Jason Coon) #17

Thanks for all the suggestions, guys! I also found these, which look very helpful (but a bit bulky): https://blinkinlabs.myshopify.com/collections/frontpage/products/led-strip-repair-kit-for-apn102-dotstar-strips-10-pieces

Stefan, that looks great! I definitely have to try that now. :slight_smile: Not sure how I missed that video. How many LEDs are in that lamp?

(Stefan Petrick) #18

4m * 60/m = 240 leds in a 20*12 “grid” (coiled on a transparent plexi tube inside the IKEA lamp)

(Robert Atkins) #19

Seconding tinning the pads makes it much easier, but you’re right, on the 144 LEDs/m strips you have to sacrifice a LED on either end so you have enough to solder onto.

(Mike Thornbury) #20

Those blinkinlabs shims don’t look like any APA102 I own - or any WS281x, either.