+Adafruit Neopixel Tiara on an Actual Tiara- Almost Built

Design change:  I have ruled out the CR1220's (not enough battery life, too hard to change), and the CR2032's (too bulky). +Becky Stern  was trying to push me towards a LiPo battery, and I resisted...but finally realized she is right. The 100mAh version is small and the right size to fit the tiara.

I sewed eacghneopixel to the tiara using silver
thread.  Here's the first, ready to go..
The "V2" on the back side happens to be on the
"data-in" pin, so I started there with each one.

Here's the tiara with pixels shown. I'm still have to clean up the stray threads.

The sewing took me an afternoon (not an expert), but I got it done and it's not too ugly.

Next I soldered the neopixels together (+ to +, - to -, DO to DI), then connected the Gemma to the first neopixel for a test, using alligator test leads--see the video. The soldering took a couple of hours. For each wire, I used calipers to measure the distance between neopixel pads, stripped 14", marked the desired length of unstripped wire (from the calipers), cut the wire 1/4" beyond, and stripped 1/4" off that end.

I did the data bus first, and used stranded wire.  That turned out to be a huge pain--it's too flexible and the ends are hard to deal with.  I switched to 22awg solid core wire for the power and GND busses. Much easier.  I will go back to stranded when I wire the Gemma, because I will need the flexibility.

Also, I discovered (or remembered, not sure which) that Gemma has an on-off switch on board.  That simplifies this circuit (I don't need to add a switch).

Next:

• trim stray threads and wire to clean up as much as possible
• re-sew at least one of the neopixels (some threads got burned during soldering)
• secure and insulate the threads and wires with nail polish
• add the 100mAh battery
• glue the Gemma to the tiara
• solder the Gemma connections to the circuit, attach the battery to the tiara.

Parts list:

• 100mAh LiPo battery
• 26AWG Silicone-coated stranded wire
• 22AWG solid-core hookup wire
• Flora RGB V2 Neopixels (6)
• Plastic Tiara (found a pack of 6 at Party City, which is 50mi away--ordered online)
• Gemma (could also use a Trinket...)
• Needle and thread
• Nail polish 
• Soldering Iron and associated paraphernalia
• A battery charger like this would be helpful

+adafruit Neoplxel Tiara on an actual tiara

This is an ongoing saga. I got the idea to put the neopixel tiara on an actual tiara for my granddaughter's Nursery School graduation in June. I could not find a suitable plastic tiara, and the the metal one I built needed so much insulation that it was ugly. Also, the Gemma and battery back make it unwieldy for a 5-year-old. Here's a video:

I found some plastic tiara's that are not great but the may do the rick. Here's a photo comparing the two:

I took the metal one down for her graduation, and I brought my spare, unwired.  She wore the plain tiara all day every day, but was not impressed by my circuit--as I said, ugly and unwieldy.So, back to the workshop. I'm planning something for her 6th Birthday this Fall.

I got lots of help from Becky Stern of Adafruit, on air on Wearable Wednesday, and on the Adafruit Support Forums. The code is the same as my Twinkling Daffodils, except that I use a different pin on the Gemma than I did on the Trinket for the Daffodils (convenience).

I took out another Gemma and programmed it.  BTW, since I last worked on this the Arduino IDE wend from 1.6.3 to 1.6.5.  I had 1.6.4 installed, with the Adafruit boards added in.  After I upgraded to Windows 10 last week, I upgraded the IDE to 1.6.5.  It was a completely painless upgrade.  I didn't have to reload any of the Adafruit stuff or any drivers, and Windows 10 did not interfere at all.

I plan to glue the Gemma behind the middle of the tiara, sew or glue the 6 neopixels in the loops (as in the metal one), and glue the battery pack to the front of the comb.  I can try CR1220s, but they will provide 40mAh.  With 20A for the Gemma and 20 for the neopixels (varyung colors and brightness and not on at the same time), they might last an hour.  (Thanks to Becky's tutorial on batteries.) The problem is that it's hard to change them.  I may have to glue a CR2032 battery holder, or maybe use the sewable holders.

Anyway, I have a fun project to work on while I'm doing the Robot Cart at the same time...and, Halloween is coming!