My wife and I were attending a gothy vampire ball pretty close to our wedding anniversary so I needed to make sure we could accessorize in a romantic fashion!
I created a pair of outlandish gothic necklaces that sense one another and glow blue when they are far apart and warm as at they get closer together until they glow red when they are near one another. I cast the necklaces in pewter from high temp silicone molds of 3d prints. The casting required a bit of trimming and sanding which is awfully annoying with pewter because it gums up files and resists cutting more than I knew. I patinated them by soaking in Pewter Black and then thoroughly polished them back out to get a really perfect antiqued finish as opposed to the bright silver metallic of the fresh pour you can see in the picture below..
The internals are an esp32 with an integrated screen. They use a low energy approach to infer their distance based on the power of the other’s bluetooth signal. The screen is illuminated with the distance-appropriate color with a brightness point gradient such that it fades to black at the edges. I also took advantage of an onboard accelerometer to implement a physics engine such that as it bounces from walking or it swings from side to side, the center of the light seems to be jostled exactly as though it were floating within it.
The whole thing is topped with an enormous large glass cabochon that I sanded the back of, applied black ink to, and then spritzed with isopropyl alcohol to create a fantastic mottled pattern that is subtle but truly makes it read as an antiqued gemstone.
I strung them with an oversized stainless steel chain that is threaded with a very thin black silicone wire to connect the battery pack that is strung on the back of the necklace. Despite some clever ways to cut power draw, the screen and bluetooth have a bit of draw so I unfortunately couldn’t hide a suitable sized battery as part of the design. I took the opportunity to make the battery compartment part of the overall aesthetic and by hanging it in the back it also balances the heavy weight of the amulet so it isn’t pulling on your neck as hard, which was actually very convenient. The compartment is modeled after an Egyptian cartourche and I was able to come up with some hieroglyphics that were fitting and, quite literally, could fit by not being too long.
Translation: “My beloved, come to me!”
Finally here are some CAD design images used for the molds:
