Here is the case for the ED Tracker DIY version connected with wire jumpers (no PCB). This way it is more compact.
Top and Bottom - the case for arduino pro micro and mpu9250 board
Bottom_curve - the glue-on bottom part of the case matching the headphones curvature (see first photo, blue part at the bottom of the case)
cable_clip - clips to hold audio and usb wires together
headphone_cable_hook - is the hook holding the usb wire (see photo 2) - this part is designed for Sony MDR-ZX770BN headphones, won't fit others.
UPDATE: Added bottom_hooks.stl - this is the bottom part with hooks for the rubber rings. Allows mounting without velcro and on most of the headsets out there.
The top lid should be printed upside down, without any supports.