Create the Gem
It's time to make your crystal gem! The gem is made from laminated cellophane gift wrap. You can cut it out by hand or use a vinyl cutter. Here is a full tutorial on how the gems are designed and made, so you can customize your own. You'll want to be sure it's large enough that the Circuit Playground board fits neatly inside the base of the gem.
If you're in a hurry or don't have a cutting machine, you can buy a pre-made crystal gem here.
The gems in the tutorial linked above are perfectly symmetrical. For this project I wanted a slightly asymmetrical gem, so it looks a little more rugged and "natural". The video tutorial in the Crystal Gems project will show you how to customize your gem using Fusion360 and Slicer. Or, you can download the files below to get the exact same gem I'm using.
Print them out and trace the pattern onto your laminated cellophane sheets, or upload the images to your vinyl cutter. I had the best success using the "stencil film" custom setting on my Cricut vinyl cutter.
Sizing: My gem's side panels are 4 1/2" tall when fully assembled. If you customize yours, it's a good idea to print it out on regular paper and assemble before making the final one, so you can be sure the Circuit Playground will fit neatly in the base.
Assemble the Gem Setting
The transition between the staff and the crystal gem is a cone shape made of a cardboard tube. The bottom of the cone should fit as snugly as possible onto the top of the staff, and the top of the cone should line up with the bottom crease on the crystal. I made the cone from two toilet paper tubes taped together with aluminum tape, and covered with translucent polymer clay.
Be sure your gem fits neatly in the top of the cone. My cone has a bit of a point on one side to help hold the crystal in place, while leaving the USB port on the Circuit Playground accessible on the other side. I covered the entire cone in a layer of aluminum tape.
Decide where you want the on/off switch and cut a hole in the cardboard that's the right size. Remember that the switch is pretty tall, so be sure you've got enough space inside the cone for the body of the switch and all the wires.
Test fit all your components before you decorate the cone. First thread the wires coming from the switch through the hole from the outside. Plug the 2-pin JST connector and the battery connector from the switch into the Circuit Playground. The 3-pin connector (for the NeoPixel strip) and the male end of the battery connector should reach comfortably out the bottom of your cone.
Roll out enough clay to cover the cone. Be careful not to make it too thin, or the clay might crack after it's done baking. Add some details until your crystal setting looks the way you want. Be sure to leave the hole for the switch uncovered. Resist the urge to extend the clay beyond the cardboard's edge -- it is pretty brittle and any exensions will likely break off.
Follow the manufacturer's directions on your polymer clay and bake it so that it hardens. For the Sculpey brand clay I'm using, I baked at 275 degrees for 15 minutes.
Assemble the electronics inside the cone, securing the switch with the hex nut you removed earlier so it stays in place. Be sure the male side of the battery connector and the 3-pin connector going to the NeoPixels reach out the bottom of the cone.
Use a small pair of scissors to cut the bottom point out of the gem, leaving flaps all around (don't cut all the way to the crease). Slip the Circuit Playground in place, with all the wires coming out the bottom, and use hot glue to glue the tabs to the bottom of the Circuit Playground.
If you want to be able to update the programming, use a utility knife to cut a small hole in the gem so the USB port is accessible. I found it helpful to be able to update the code after the staff is assembled, so I can tweak brightness and mode triggers while using the staff.
Use hot glue to secure the gem inside the setting.
Make the Staff Tube
To diffuse the NeoPixel strip inside the main part of the staff, I used a white marabou feather boa. I spiraled the feathers around the 1/2" tube containing the NeoPixel strip, then slid the whole thing into the large outer 1" tube. The feathers keep the inner tube centered and do a pretty good job of diffusing the light.
I wrapped a piece of gaffer's tape around the top edge of the staff, to give the crystal setting cone a nice tight fit.
The NeoPixel connector should stick out of the tube by a couple inches. The cylindrical battery fits inside the top of the tube as well, right alongside the connector.
I added a few more feathers and a leather cord for decoration.
I wanted a bit more diffusion, and also to take the shine down on the plastic, so I used a piece of 80 grit sandpaper to sand the tube all along the outside. The sanding combined with the feathers makes an absolutely beautiful diffusion.
Plug the connectors from the crystal assembly into the battery and NeoPixel strip. Slide the crystal assembly onto the top of the staff. You may need to add some more tape or padding inside the crystal assembly so it doesn't wobble. You want it secure, but removable -- you'll need to take the head off in order to charge the battery.
I made a second cone-style assembly for the bottom of the staff using the same cardboard, aluminum tape and polymer clay method. Slide the cone onto the bottom of the staff and cap the staff with an end cap to hold the bottom cone safely in place.
Decorate the staff with feathers, leather cords, bones, runes, or whatever other magical design elements your character requires.