Finishing Up

These steps mostly apply to the pendant design. If you’re making a votive or other installation, you’re pretty much done with the guide and just need to devise your own mounting scheme (hot glue, tape, or your own 3D-printed support)…but skip down to the bottom of this page for notes about charging.

Apply a small piece of tape to the back of the Pro Trinket board, covering the JST pads and wires. The matrix will sit very close atop this and we don’t want any shorts if something is flexed around.

It doesn’t need to be fancy Kapton tape like this…ordinary masking tape or a couple layers of office sticky tape will work just fine.

Press the power switch into its space in the back of the case, with the slide bit poking out the hole.

A little bit of glue helps secure this in place…5-minute epoxy is ideal, or E6000 if you’re patient…but in either case, do not get any glue inside the switch (those two little notches on the side lead straight in). Use a toothpick and apply glue near the side flanges or down near the legs.

Make sure the switch is straight while the glue sets up…pinch it with something if need be. E6000 needs at least a couple hours to really firm up, so you’ll be taking a few breaks if that’s what you’ve got. Even “5-minute” epoxy should be given more than 5 minutes…15 or 20 is a good start.

The Pro Trinket and LiPoly Backpack are next…various notches and nubbins line up with the mounting holes on these boards, but you’ll need a few small dabs of glue to keep them permanently in place.

Make sure no wires are tangled underneath the boards! Get that all straightened out, then glue the boards down.

Hold this in place with tape or rubber bands or a clothespin or such while the glue dries.

The LED matrix sandwich then sits on top, also with mounting nubbins and a couple dabs of glue. Use tape or rubber bands to hold it while that dries.

It’s normal that the matrix “leans” along the length of the case…it’s designed that way, slightly tapered. But make sure it’s straight in the other direction.

Once the glue is dry, pinch a kink at the midpoint of the battery wire, then tuck this underneath the other electronics…it’s a tight squeeze, but should all fit.

Fit the case front over the matrix, then add two screws (#2-56 x 3/8" or M2 x 10mm).

The screw sockets aren’t threaded…3D printing lacks the resolution for that…you can either add threads using a tapping tool if you have one, or just grind the screws into the plastic ’til they bite, and tighten until the back fits securely and the screw heads are flush below the surface of the case.

If you accidentally strip the threads…well, more glue. No biggie.

Test it once again, making sure everything still works.

Add a fancy necklace chain or a simple nylon or leather cord, whatever suits your style!

Fully charged, the 350 mAh LiPoly battery should provide about 4 hours run time. When it’s nearly depleted, the flame may flash a few times before turning off completely.

To charge, switch it off and plug in a USB microB cable. LEDs on the edge indicate the battery charging status: a red LED indicates charging, while a green LED on the corner (not the one near the USB plug) lets you know the battery is full. A 100% charge from a fully-depleted battery will also take about 4 hours.

If you’re installing this in something other than the pendant, you have the option of using a higher-capacity battery (500, 1000 mAh or more!) with a proportionally longer run time. If you go this route, there are two pads on the back of the LiPoly backpack that can be bridged with a dot of solder to enable a faster 500 mA charging rate. Do this only if using a 500 mAh battery or larger!

Last updated on Apr 15, 2016 Published on Apr 15, 2016