Designed with TinkerCad.
Printed with ESun3D Transparent Blue PETG filament. I used the standard settings for Generic PET in Slic3r Prusa Edition, but I slowed the first layer to 15mm/s to fix adhesion problems.
The electronics are an Adafruit Feather ESP32 with a 12x6 DotStar FeatherWing. I used headers to stack them. The battery compartment is plenty of room for a 500 mAh LiPo and there's a port for charging the tag without taking it out.
I cut a rectangle out of transparency sheet to use as the window. The loop is for a lanyard and then I added a couple of wholes to run some EL wire through to make it to loop around my neck to make it more eye catching.