MAXduino case for TZXduino / MaxDuino board from ProjectAVR

I bought this "MaxDuino" board on eBay. It emulates a tape player for retro-computing. As I intend to use the board for my Acorn machines, it was modified to support Motor Control via the 3.5mm stereo plug.

Design

I used Fusion 360 to design a simple case that has a slot for the MicroSD card, a cutout for the OLED display as well as 3.5mm audio out and the mini-USB power connector. All model files are available.

PrusaSlicer settings

• Plater presets: 0.2mm Quality, Prusament PETG
• Print Settings  > Layers and Perimeters > Vertical shells, increase to 3 perimeters
• Print Settings > Support Material > uncheck "Don't support bridges" (Advanced mode setting)

--> By default, PrusaSlicer will NOT create supports under long bridging sections. The results were very poor with this default value.

Supports

• Choose "everywhere" for the supports to ensure the USB / audio / MicroSD ports are printed correctly
• Then, use the "Paint-on supports" feature to REMOVE (right-click) supports from the icons on the buttons

Printing

• I used PETG "Prusament" filament on my Prusa Mini printer.
• Temperature settings etc. are left at default.
• The top case is printed as a single part; the buttons are "hinge-type" just like on the Prusa Mini.
  • This takes about 2.5 hours to print
• The bottom cover takes about 45 minutes to print

Assembly

• The PCB fits quite tightly; you may have to slightly bend the case outward to allow the USB and audio connector to slide in
• The bottom cover plate protects the PCB from short-circuits and other damage; it uses small 3x12mm self-tapping screws

Result

Overall I'm quite happy with this first revision of the case:

There is some room for improvement:

• The MicroSD cutout has large overhangs that do not print nicely, even with full supports enabled.
  • Not sure how to improve this - I'm open to suggestions
• The button icons have fairly large overhangs that are not always printed nicely.
  • Perhaps use outlines instead of cutouts to improve print quality?