I'm using solid core wires for all the connections between the boards and NeoPixels, and silicone stranded wires to reach to the on/off switch. The solid core wires will give us strength and stability for the components that need to stack tightly together, and the stranded wires will give us flexibility in terms of the on/off switch placement.
Any type of wires will work, but I found this method to be the easiest to assemble.
Cut two small pieces of solid core wire in red, white, and black.
Cut two slightly longer pieces of silicone stranded wire for the on/off switch, and two pieces of heat shrink tubing.
Connect a stranded wire to the middle leg and to one (it doesn't matter which) of the outside legs of your on/off switch. Solder and cover with heat shrink.
To enable the on/off switch take a knife and scratch the copper trace between the two pins marked Pwr Switch. Solder the two stranded wires from your switch into these two pins. It doesn't matter which wire goes into which hole.
Solder the other solid core wires into the NeoPixel jewel:
- Red into PWR
- Black into G
- White into DIN
I've found it's easiest to insert the wires into the holes from the front and solder on the back of the jewel. It seems counter-intuitive, but it's very hard to reach between the LEDs on the front of the jewel with your soldering iron without damaging the NeoPixels.
Putting It All Together
The LiPoly backpack is designed to sit on top of the ItsyBitsy, but that would make our components stack too thick. We'll place it right next to the ItsyBitsy for a lower final profile.
Place the charger alongside the ItsyBitsy and trim the wires carefully to reach the appropriate holes:
- BAT to BAT
- G to G
- 5v to USB
The wires will cross each other but it's possible to get them into a nice, neat package. Solder them in place.
Flip the ItsyBitsy and charger over - we'll attach our NeoPixels to the back of the boards. Center your Jewel and solder the white data wire to pin A1.
I'm using a 3V ItsyBitsy, which has no more available ground pins. It does have a power pad and a ground pad available, however. There are two copper pads on the back of the board intended for soldering on a JST connector, in case you want to connect a battery directly to the ItsyBitsy. We can solder our NeoPixel PWR and G wires to these pads.
Tin the pads generously, then trim and strip the red and black wires. Attach the red wire to the right side pad (with the USB port facing away from you) and the black wire to the left side pad.
Plug your battery into the battery charger's JST port and test to be sure everything is working. If you've uploaded your code, the NeoPixels should light up in a beautiful shifting ocean palette.
If this is still too big and you want to make it even smaller, you can shave a couple more millimeters off by connecting the battery directly to the charger instead of using the JST port. The technique is similar to the one you just finished - we'll solder directly to the copper pads currently holding the JST connector in place on the LiPoly backpack.
This is an advanced option for a reason! Lithium Polymer batteries can be dangerous if shorted or punctured. They can catch fire and fill your lungs with toxic smoke. So be sure you know what you're doing before attempting this modification. A sloppy solder job could wreck your project.
Flip your power switch to the OFF position.
Use flush cutters to carefully snip through the solder holding the front of the JST connector to the battery charger. You should be able to carefully snip both corners and then gently pull the JST connector off.
Trim off your battery's JST connector by snipping the red wire ONLY, then soldering to the + pad. Then snip the black wire and solder to the - pad.
Don't cut both wires at once as this could short your battery through the metal snips. Cutting one wire at a time, then soldering, is the safest way to avoid a short, which could damage your battery or components.
Make extra sure your soldering job is clean and the two pads aren't bridged before flipping your switch to the ON position.