[WIP] Case and hang tag for Waveshare 2.7" NFC display module

This is a case and hang tag for the Waveshare 2.7" NFC-powered display module.  It is designed to be water-resistant by having a TPU piece act as a flexible gasket and hang tag.  It was inspired by my lovely neighbor Bruce, a transit enthusiast who wanted a reusable bike hang tag for CalTrain trips.  

The bottom shell and top faceplate/bezel are printed with normal plastic (I like PETG for its ease of printing and durability) while the middle gasket/hang tag is printed in TPU with. The TPU tag is designed to perfectly fit on a 256x256 mm build plate, such as the Bambu P1/X1.  The file can be edited to fit larger plates, but anything significantly smaller will have issues keeping the tail long enough to wrap around a pole or bike frame.  Infill is only used for some parts of the bottom shell, but keep it >30% to protect against crushing.  The TPU should have a moderate infill of 20~30% so it compresses as intended.  

To assemble, insert the display into the bottom piece, making sure the recess lines up with the bottom SMD components on the module.  Then slide the hang tag part of the TPU layer through the hole from the inside.  Finally, push the bezel straight down on the TPU layer to compress it and create a seal.

This project is unfinished.  The TPU layer needs tweaking so it can be compressed enough to seal out water without popping the bezel back out.  The snap-in bezel could also use tweaking to be as secure as possible.  The PCB part in the file is not intended to be printed, just used as design reference.  The overlaps with the PCB are intentional to allow for the gasket to compress and create a water-resistant seal.  The minor gaps are also intentional to allow for some tolerance; they aren't big enough to impact waterproofing.  This was completely made in FreeCAD 1.0 and you will have to export the parts from the FCStd file for printing.