Color Changing Bling Ring

This 3D printed ring holds an illuminated, color-changing "gem" to brighten your night!

Materials:

• (1) CR2032 Coin Cell Battery
• (1) 4x3x2mm color changing rectangular LED. You can also use a 3mm round LED, but it won't fit as easily against the ring.
• Transparent PLA Filament
• Opaque PLA Filament (a silver grey looks nicely "metallic" here)
• Small amount of clear epoxy or similar glue

Tools:

• 3D Printer
• Fine nosed pliers
• Wire cutter/flush cutter

Print the body of the ring using opaque PLA filament from the STL file, "LEDRingCR2032.stl." To capture small details set the printer resolution to a 0.1 mm layer height or smaller.

The rectangular compartment in the front of the ring holds a CR2032 coin cell battery. The legs of the LED thread through the holes in this compartment so they contact the battery and complete a simple circuit. Viewing the ring from the front, the positive LED lead passes through the holes on the left side of the battery compartment and the negative LED lead passes through the two holes on the right side of the compartment. The next section goes into more detail on the technique for attaching the LED to the ring.

Gather the printed ring body, the color-changing LED, and a pair of find-nosed pliers. Identify the shorter (negative) leg of the LED. It is important that the LED leads are inserted into in the correct holes in the ring, or it will not light up. As shown in the first picture, bend the very end of the negative lead into a small half-circle about 8 mm in diameter. Thread the negative lead through the two holes close to each other in the front of the battery compartment as shown in the picture. It may take a bit of fiddling and re-bending the lead to get it to thread into the first hole towards the middle of the ring and out the second hole on the side of the ring. Once you get the tip of the leg pointing out the second hole, use the pliers to firmly, but gently pull it through a bit more so that it won't slip back. Don't pull it all the way through yet.

Next, push the tip of the positive lead through the hole in the left side of the battery compartment and push it straight through until it exits the hole through the opposite side in the compartment. Once both legs are threaded, use the pliers to pull them through their holes until the LED sits very close to the front of the ring. Gently bend the head of the LED upwards until it is oriented vertically against the front of the battery compartment. Bend both leads where they exit the battery compartment, and trim them just past the bend using the flush cutters.

Test the assembly by inserting the coin cell battery into the compartment with the negative side facing the LED. The first time inserting the battery may require a moderate amount of force. It may help to invert the ring over the battery on a tabletop and press the ring down until the battery slips into the compartment. Once the wires are settled, subsequent insertion/removal of the battery will be easier. If assembled correctly, the LED will light up. Now remove the battery before the next step.

Using translucent filament, print either the heart or star-shaped gem, using 0.1mm layer height. Place a small drop of epoxy or other clear glue on the end of the protrusion inside the gem, and slip the gem onto the ring so that the protrusion sits between the prongs on the ring body. Allow the glue to dry according to the directions on the bottle.

Once your ring is finished, insert the battery into the compartment and slip it on any finger (the slot in the ring lets it expand to fit a range of finger sizes). Enjoy wearing your new glowing jewelry!