It's time to solder the strips. This will take a bit of patience and care so give yourself some time, put on your favorite podcast, and don't rush it. You'll want to test each LED strip as you solder and be sure your solder points are rock-solid since one bad pixel or bad joint can make all the LEDs downstream simply stop working.
The 120/m strips are quite a bit easier to solder than the 90/m strips because of the way the pads are laid out. With either kind of strip, we'll use the "sacrificial pixel" method of cutting since the pads are so tiny. This means that instead of cutting through the center of the pad, and trying to solder wires to a half-pad on both ends, we'll cut one pixel out entirely leaving full, intact solder pads on each side.
Start by connecting the in end of your first strip to the Circuit Playground. Cut off the connector and the additional ground wire. Solder the red wire to VOUT, the white wire to A1 and the black wire to GND.
Decide whether your first strip will be facing up or down on the corset (determined by which way you want the lights to face). Use some hot glue to secure the wires and the top of the strip to the back of the Circuit Playground. Pin the Circuit Playground to the center front of the corset. Measure to the bottom with the LED strip and cut, leaving an entire solder pad on the end of the strip.
The easiest way to determine the correct length for each strip is to pin it carefully to the corset through the silicone sleeve. Pay attention to both the data flow direction and to which way the LEDs are facing as you lay the strips out. We'll connect them together in a serpentine layout. This means the data IN is at the top for the first strip (connected to the Circuit Playground) and at the bottom for the second strip, to keep the wires as simple as possible. You can mount the strip either face up or face down to control which way the lights shine.
Cut each strip to the perfect length, remembering to leave a full solder pad at the bottom AND at the top of each strip. You'll sacrifice a few pixels, but your fingers will thank you later.
For now, leave the cut strips pinned to your corset. This will keep them organized and make it easy to determine the right length of wire for the connection points.
We'll solder the right side strips together, then add the on/off switch and battery connector, then solder the left side, ending at the front. This will place the battery and switch right at the back of the corset where it's out of your way.
Putting the battery in the middle of the LED strips is a great idea since we have so very many pixels. Power can travel either direction through the strips (though data only flows one way). By placing the battery in the middle of the strip, none of the pixels end up really far away from the power source. If power has to travel too far, it tends to get weaker, which means your pixels could "brown-out". Nobody likes browned-out pixels.
Prep your ribbon cable. We only need 3 wires, so look closely and find the striped wire. This will be our POWER wire. Pull on the non-striped wire on the opposite side of the cable and strip it off, leaving a 3-wire strip. Save the extra black wire for another project.
Separate the three remaining wires about 1/2", and strip a tiny bit off the end of each. On the bottom end of your first LED strip, solder the striped wire to +, the middle wire to DO and the remaining wire to G.
Cut your ribbon cable so it's the right length to hop over to the next strip on your corset. The IN end of the pixels should be at the bottom on this strip, so that means you'll only need a few inches. Cut it to length and solder to the new strip the same way: striped wire to +, middle wire to DI and remaining wire to -.
Time to test the strip! Plug a battery into your Circuit Playground and be sure both strips light up.
If everything is working, it's time to secure the end of the strips. We'll use clear heat shrink and hot glue to make the joints rock-solid, so they never wiggle apart while you're wearing the corset.
Cut a small piece of 1/2" clear heat shrink and slip it over the end of the strip. Squirt a little hot glue inside, and use a heat gun to shrink the heat shrink while the glue is still wet. This will create a solid plastic housing for your solder joints that will be virtually unbreakable.
Continue with the rest of the strips going around the right side of the corset. When you get to the back, solder on a long (at least 12" or longer for a larger corset) piece of ribbon cable to the end of the last strip. It's time to add the battery cable and on/off switch.
About halfway down this long piece of ribbon cable, separate the three wires and clip the two outer ones, leaving the middle wire intact. Strip a little off the cut ends and twist each wire back together with itself -- striped wire to striped wire, non-striped to non-striped. This bit of silliness will give us a connection point for the switch.
Plug the battery into your JST extension switch and notice which side you used. Leave this side alone! This is the male side, and it's for plugging the battery in. Unplug the battery again.
Cut off the other end of the JST extension cable (the female side). Separate and strip the wires. Solder the red wire to the striped wire connection point and the black wire to the non-striped point, remembering to slip on some heat shrink before soldering.
Plug in your battery and click the on/off switch. If all goes well, your lights and Circuit Playground will come on. Hooray! Be sure everything works right, leave another few inches of ribbon cable, and continue with soldering, testing, and sealing the rest of your NeoPixel strips.
Add a rubber band around the battery, trapping the leads inside. The connections are really delicate and will break if you don't provide some strain relief.
Page last edited March 08, 2024
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