Anelok: case design (2/3): interim result

Werner Almesberger werner at almesberger.net
Fri Jul 10 19:55:53 UTC 2015


The case design I have so far looks like this:
http://downloads.qi-hardware.com/people/werner/anelok/tmp/case-interim/render.png

The big yellow rectangle is the polycarbonate "glass". Underneath
it are OLED panel and the sub-PCB with LED and slider. Additional
details like FPC, USB connector, battery, and the mounting holes
for the screws can also be seen. The toroidal lanyard hole is in
the upper left corner.

The overall design is quite similar to what I've shown before, but
there are two noteworthy differences:

- the case has grown to 52.0 x 45.25 x 14.0 mm = 32.94 ccm

- I moved the memory card holder such that it ejects (again) into
  the battery bay


A closer look - first, the bottom half:

http://downloads.qi-hardware.com/people/werner/anelok/tmp/case-interim/bottom.png
http://downloads.qi-hardware.com/people/werner/anelok/tmp/case-interim/bottom.stl

This part is quite simple: left to right, there is half of the
battery holder, with a cut-out in the middle for the memory card,
then the barrels into which the screws (length 8.0 mm) go, and
then three lugs (or whatever one would call such things) that hold
the bottom half in place at the thin side of the case.


The top half is more complex:

http://downloads.qi-hardware.com/people/werner/anelok/tmp/case-interim/top.png
http://downloads.qi-hardware.com/people/werner/anelok/tmp/case-interim/top.stl

There is a cut-out for the head of each screw, and the side wall is
thickened correspondingly to mantain minimum wall thickness (1.5 mm).

There are various "ring-shaped" cut-outs around the PCBs and also
around the panel. They define the horizontal position of these
parts and, in the case of the PCBs, they also constrain vertical
movement in one direction.

The main PCB is supported by little ramps that should snap under it
when inserted. I.e., the PCB shouldn't fall out when opening the
case to replace the battery.


The FreeCAD Python script that generates everything is here:
https://gitlab.com/anelok/anelok/blob/master/me3/case.py

Next: things I don't like.

- Werner



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