3D Scanning

Werner Almesberger werner at openmoko.org
Sat Jul 24 03:25:43 EDT 2010

James Xakh Lynch wrote:
> why don't we just put a kickstand on the top of the screen,

Hmm, wouldn't that be fumbly and easily breakable ? What may help
a bit is to move the rear feet back a bit. E.g., by extending the
lower shell under the hinge, one would gain about 2 mm and
something like 20-40% of the torque needed for balance.

> It seems sort of pointless to make a counterweight, and waste
> valuable internal space.

In this case, the internal space is already wasted. I'm just trying
to put it to good use :)

But I agree that a counterweight isn't optimal. A cleaner solution
would be to reengineer the case. This can of course get expensive.
A lump of lead is cheap and RoHS is for wimps anyway ;-)

One could try to make the display's inside lighter (e.g., avoid the
large PCB, which should add at least 5 g for the bare PCB alone),
reduce the weight of the display case, maybe remove the metal at
the top of the display case, maybe rearrange the internals in the
bottom case such that everything heavy is closer to the front.

Here's a weight breakdown:

- display module plus PCB, 26.7 g
- bottom shell and outer display shell, 32.7 g. The assembly's center
  of mass is about 9 mm into the display shell, so I'd estimate the
  weight of the display part at about 20 g.
- display front plastic, 4.6 g
- display sticker (glossy black/transparent), 2.9 g
- battery cover, 3.8 g
- keyboard frame, 2.3 g
- main PCB, 20.7 g
- battery 18.6 g

The keyboard is in the scanner. I'll weigh it later. It feels quite
heavy, maybe 20 g or more.

The Giantplus data sheet doesn't specify the weight of the display
module. Do we have that information somewhere ?

- Werner

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