Adding the Clasp
Thread the two long black wires through the top of your pendant. I wound a piece of jewelry wire around the neck of my turtle to hold the wires in place and help with strain relief.
Hold your necklace in place around your neck and decide how long you'd like it to be. Add an extra inch or so to the wires and snip.
Strip the wires that full inch -- you want a lot of bare wire here -- and slide a short piece of heat shrink tubing over the ends.
Slip the bare strands through the hole on each side of your magnetic clasp, just about all the way up to the wire shielding. Wind the bare ends around and around and around until the necklace clasp feels secure. If you can, thread the wires through the clasp's hole a second time. You want a lot of metal-on-metal connection here.
DO NOT SOLDER these in place! A weird property of magnets is that if you heat them up past around 500 degrees, they will lose their magnetism. Sad Christmas! So wind the wires around really really well, then add a dab of hot glue and slide the heat shrink over while the hot glue is wet, then shrink it on down. Pull gently on the wire and the magnet to make sure they're firmly in contact while the glue setsup so you have a good strong connection.
Add a little hot glue around the inside of the pendant and press your lights in place. Try it on! How does it feel? (If the JST connector is a little too prickly and cornery for you, sand down the edges a bit)
If that JST connector is just too bulky (and it's amazing how bulky a JST connector can be), advanced users can desolder it from the charging backpack and solder the wires from the battery directly to the JST pads. Be sure not to mix up positive and negative battery wires or the whole thing might just catch fire. Cover up the connections with some hot glue to secure them in place.
Care & Feeding
Enjoy your necklace! To charge, simply plug a micro USB cable into the port on the Trinket for a few hours. The charger has an indicator light to tell you when it's done. Depending on how you decide to set the brightness in the code, this necklace will glow all night long -- and when the battery dies, the glow in the dark polymer clay will take over!