I would really love to be able to mouse without leaving the DH. [...] For me the best two options to put a trackpoint-style 'nubbin' would probably be ...
I quite agree with you about the desirability of incorporating some type of pointing
device into the design. It is already supported in a couple different ways by the PCB,
but there is no final or perfect solution identified.
Along with the couple options Turbinia has proposed with his case design
(
http://geekhack.org/index.php?topic=41422.msg1060497#msg1060497 ) ,
I quite like what gator456 did here:
http://geekhack.org/index.php?topic=12212.0I do not believe that packaging will allow your #1 position, though I think it would
be comfortable. I'm not personally a fan of your #2 position, as it seems awkward to
me. I'm also not sure that the parts will be able to fit in that spot.
If you used your middle finger in the same way as you're using your index finger in #1,
I think that could be supportable, and comfortable. ( my understanding is that you're
imagining the "nubbin" to be sticking out of the front edge of the palm support ).
Please note that I have not been concerned with being mechanically compatible with
the existing DataHand PCBs. You might be able to achieve that by tweaking my OpenSCAD
dimensions, but I have not been targetting that. I am targetting a complete replacement,
and therefore new PCBs too. Along with that will come complete control over your layout
and key assignments - the joy of a custom keyboard.
The feel of the center switch (and the others for that matter) is greatly affected by the shape
and mass of steel in the clips to which the magnet is drawn. If you wanted to increase the
force required to release the center key, you could choose to make clips out of 0.020" material
instead of 0.015" material and make them 0.050" wide rather than 0.045" or anywhere
inbetween. This is a wide range of release force. I bet you could be happy somewhere in there.
I have not considered using a cherry switch in the center because 1) MX are too large, 2) I want
to maintain the feel of the magnetic release on the switches.
I was wondering if this design still uses optical switches (which have the disadvantage of potentially not working in direct sunlight)
If it is so, why? Is there a viable alternative?
I am primarily a coder. I work best in the dark, far from windows. I've only ever had a
direct-sun-on-my-datahand experience one time in my 15 years of use, and while I
found it initially confusing, I just had to slightly adjust the horizontal blinds and the
"problem" was solved.
Anyhow, the real answer is that I couldn't come up with a better solution.
This approach allows me to create a reliable switching mechanism in a
funny, small, custom package without the need of making super-high-tolerance
electrical switch contacts. I'm an EE by degree, and a software guy by trade.
I'm sure that the ME's (and people with access to Pro-E!) look at my stuff
here and mutter, but I'm only concerned with getting something that works.
A tangible, working design that will hopefully be improved upon, but can be
used as-is.
However, more to your point: 3D printing allows some easy improvements to
the original in terms of shielding. I have no data to prove it, but I expect that
I have improved on the resistance to ambient and IR light through being able
to have the IR phototransistor snap partially into a box which shields its front
completely and does not expose the eye from above at all. Should be better.