This project was a commission for Christian Joy Costumes. I happily soldered up this circuit on top of a headband she created.
Parts used (~$160):
Step 1: Solder LED Strips
To attach wire to the input end of a NeoPixel strip, tin the outer pads and the ends of the wires. Then solder one wire to each of the two pads you just tinned. Flip the board over and tin and solder the remaining wire to the center pad. Use flush diagonal cutters to trim the wires if they extend beyond the pads. Alternating sides of the board helps prevent short circuits.
Step 2: Attach LED Strips
The design has NeoPixel strip "dreads" inspired by Phil Burgess' technique used in his Cyber Falls Wig. The combo of hot glue and heat shrink tubing helps reduce wire strain.
Sew some small bits of elastic to the crown ring and use zipties to attach the strips. I ran the wires through the existing accent strips so that they are hidden from view and potential snags. Now when the performer shakes around and the strips pull, the elastic stretches before pulling on any wires.
Step 3: Test LED Strips
It's important to test a project like this at key milestones. Solder all the power wires together, all the ground wires together, and all the data wires together and temporarily use alligator clips to hook the strips up to an Arduino compatible microcontroller for testing (NeoPixel strandtest is sufficient).
Step 4: Build Front Motif
The front motif of this headpiece is just a bunch of NeoPixels hand wired together. Rings have single pixels at their center, bridged with pixels cut from a larger strip. This was very fun and satisfying for me to build, but you may find this part tedious. At least we can agree it's great soldering practice.
Test the circuit after adding significant elements, and use clear nail polish to coat the exposed contacts as you go (to help the circuit stand up to sweat).
Step 5: Finalize Microcontroller Circuit
Once I verified that the circuit was operating properly, I tidied up the wires and routed them to a single place where I soldered them to a Feather 32u4 Basic Proto board. A switch toggles the power connection to all the NeoPixels, so that the battery may be charged without the LEDs on.
Step 6: Battery & Code
Since this project was for a client, I included a charging kit with a USB cable, micro lipo charger, extra power supply, and extra battery. The batteries have a little E6000 adhesive squished into the tape where the wires join, to help prevent them from getting fatigued and broken.
The final design we settled on was a pink and yellow gradient across the front and down the crown strips. The NeoPixel code is based on Bill Earl's multitasking base code. I created arrays of pixel IDs from across the front motif to create an even gradient across.