Introduction: Make Custom LED Strips
I recently made an infinity mirror cube and I wanted to have it be a specific size with a specific number of LEDs. None of the LED strips that I could find had the correct characteristics for what I wanted, so I made my own. These strips are not flexible, but that wasn't necessary for my project. The basis for these strips are custom designed circuit boards. I didn't make the boards myself, but I did design them. This Instructable is about the process of assembling these strips after I received them. I plan on coming back to this Instructable and add some steps about the design concepts.
I don't currently have an Instructable about designing these boards, but I did make a video describing the design. Maybe it could help you design your own if you choose this method. You can view that video here: https://youtu.be/o1eelFdcL0A
I also have a video that shows the steps from this Instructable. This video is actually about the whole infinity mirror cube project, but the assembly of these strips is in there, close to the beginning. You can view that video here: https://youtu.be/tmyQh9ZPkBg
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Step 1: Assembling the LED Side
My LED strips are about 3 inches long with 8 LEDs per strip. When assembling the surface mount components to all of the boards, I tried several things. Here is what was the easiest/quickest method that I have tried so far.
To attach the LEDs I started by putting some solder paste on 2 of the solder pads for each LED. Next I positioned each of the LEDs onto the board. Using a soldering iron with a bit of solder on the tip, I melted the solder paste to attach the LEDs to the board at those 2 connection points. For the other connections I applied some solder flux, then soldered them as normal.
Step 2: Assembling the Connections Side
Since the surface mount capacitors the LEDs need are very small, I needed a way to hold them in place while I soldered them. At first I just held them with my tweezers, which worked well, but took a long time holding everything steady. Here is what worked well for me:
Using a board with 2 screws, tied a string to one of those screws and wrapped the string around the other screw. This let me pull the string tight when I needed to hold the capacitor in place. I slid the strip under the string, put the capacitor in place, then carefully lift the string and position the capacitor beneath it. The capacitor will probably shift a bit, but pulling the string tight let me move the strip to re-position the capacitor. Next I apply some solder paste to one side of the capacitor and solder it in place. Now I could easily solder the other side of the capacitor in a normal manor. You can see that the solder paste leaves behind a bit of a residue, so don't forget to clean that up with rubbing alcohol before using these.
Step 3: Testing the Custom LED Strips
After soldering all of the parts to the strip, it's important to test it out. I connected it to an Arduino so that I could test it and make sure my soldering job works. If only some of the lights come on, there is likely a poor solder connection on the next LED. Re-solder it, then retest it. Make sure all of the LEDs light up before calling that strip good.
Step 4: And That's It!
And that's the custom strips! I'm currently working on an instructable for the infinity mirror cube, I'll add a link here after I finish that. Any tips on making this process easier is welcome. Also, I would love to know what other projects these types of LED strips would be great for. Thanks for checking out this Instructable!