[Arm-netbook] http://rhombus-tech.net/community_ideas/kde_tablet/news/

[Luke Kenneth Casson Leighton]

On Mon, Dec 8, 2014 at 2:25 PM, joem <joem at martindale-electric.co.uk> wrote:
> On Fri, 2014-12-05 at 16:15 +0000, Luke Kenneth Casson Leighton wrote:
>> On Fri, Dec 5, 2014 at 3:30 PM, joem <joem at martindale-electric.co.uk> wrote:
>> > On Thu, 2014-12-04 at 23:45 +0000, Luke Kenneth Casson Leighton wrote:
>> >> started on a first revision of the tablet casework, as a pyopenscad
>> >> program, using a blender-exported STL as the "ghost" template to work
>> >> out how the case should surround the parts.  it's done as layers so
>> >> may either be made of wooden laminates or 3D printed and assembled
>> >> using screws/bolts.
>> >
>> > I got limited wood veneer about 1mm thick to make own laminate cut with
>> > laser. Let me know where to download the dxf file (or whatever), to try
>> > make something.
>>
>>  http://hands.com/~lkcl/3dcase.tgz - do you know how to take dxf
>> slices from openscad?  if not i'll rework the python code to generate
>> dxf files directly.  don't be confused by the name car_model.py ok? :)
>>  pyopenscad.py is included in the directory so will be imported
>> directly.
>>
>> > My guess is that if its got curved surfaces,
>>
>>  no, and that's deliberate.  i arranged it so it's possible to laser-cut.
>>
>>  ok so only 1mm veneer, hmmm, you can get away with that.  thicknesses
>> are meant to be 1.5mm, 3.0mm, 4.0mm and 2.5mm however you could get
>> away with either one or two 1mm, then 3mm, 4mm and 2mm (just about).
>> base could be 1mm as well.  the1.5mm is a surround for the
>> touchscreen.
>
> Not really a problem - after gluing,
> sand the surface to requirements.

 no gluing required: there are 10 screws, 5 top 5 bottom, which will
hold it together nicely.  i think the top sheet should be 2.0mm not
1.5mm so that it sticks above the top.

> Layering the sheets can generate the required thicknesses.

 i realised

> I got limited thin ply and plenty 4.3mm ply that can
> be laser cut. (Usually only birch plywood cuts well with
> laser.) I got thin sheets of mylar (easy to cut with laser)
> that can be used to increase electrical isolation (in case
> the veneer is permeable to moisture around critical parts).

 *thinks*.... shouuuldn't bee.....

> It should be easy to slice 3D model into dxf files.
>
> (My personal thoughts are that it would be easier to do this
> project scripted in openscad instead of openscad.py
> only about 10 or 20 commands to learn.)

 i'm a software engineer: i looked at openscad and went "this is an
assembly-level set of instructions not a programming language".
pyopenscad i can - and have - defined variables, re-used code, created
parameterised procedures and have been able to keep the code short,
flexible and to the point.

> Any way I have a try to convert to dxf slices and make it.

don't worry for now: i will convert the code to output DXF files
directly, then use the pyopenscad DXF import-then-extrude function to
extend it to 3D.  that way i can double-check it surrounds the
blender-generated STL file properly.

 ... *deep breath*... but.... hold everything, i've never been a great
fan of the 1024x600 LCD panels, and the LG one i *thought* was the
only possibility... but now i realised that there's a way to use the
HSD070PWW1 (which is very popular, even to the point that it's
available on adafruit) by redesigning the PCB so that it is 160mm x
65mm rather than what it is at the moment.

 and, as that's a 1280x800 LCD i will actually *like* it.  that will
encourage me to get this thing right, because i will actually want to
use it myself.  if you've ever tried using a 1024x600 LCD, they're
crap.  the KDE control panel for example doesn't even fit on-screen!

 then, also, i will have [just] enough room to fit a 2nd FPC connector
which will take the 10in HannStar 1280x800 LCD... which funnily enough
is _also_ on adafruit.  i'm currently checking the power output from
the AXP209 because i reallly don't want to redesign that area,
converting to use the AXP223 for example!

l.