[Tfug] Most stable laptop video drivers

[Bexley Hall]

Hi Zack,

On 1/18/2013 12:28 PM, Zack Williams wrote:
> On Thu, Jan 17, 2013 at 11:37 AM, Bexley Hall<bexley401 at yahoo.com>  wrote:
>> Ages ago, I had built a mouse (trackball) from a bowling ball (!).
>
> If you have pictures of that, I'd love to see them.

<frown>  Unfortunately, most of my career predated digital cameras!
I have "polaroids" of some of the projects that I worked on -- though
they are pretty poor quality (the lack of immediacy in viewing the
result of the snapshot has a huge effect on how many photos you
take and how well you "tune" your vantagepoint, etc.)

They are actually easy to make (especially with the low power MCUs
available nowadays).

I used a pair of 1/2 dia drill rods mounted in "pillow blocks"
to support the ball (parents worked for a company that manufactured
ball bearings so $100 pillow blocks were easy to come by!  :> ).
You put a slotted disc on each shaft driving a photointerrupter
(i.e., open frame opto-coupler).  Then, feed a two bit FSM to
decode step-plus-direction for each shaft.

A bowling ball would be a bad choice, nowadays.  At the time, I
used to work on a tall bench and sit on a very tall stool -- so,
my feet wouldn't even touch the floor, normally.  To do it
over, I'd start with something more like the size of a bocce ball
(not the pallino) and make the enclosure with a sloped "top"
(sort of akin to a footrest).  And, put the two mouse buttons
mounted sideways above the plane of the "ball support" so you
can pivot your foot on your heel and swing the toes left or
right (swinging OVER the top of the ball without contacting it)
to touch the left or right switch, respectively.

[I had the buttons -- *four* of them -- controlled by the other foot.]

But, I'd still opt for a ball made of stone or some sort of
composite material -- not metal -- so it has a fair bit of
heft/mass/momentum/inertia.  I think this is necessary to keep
the ball from "wandering" as you lift your foot off of it.

I'd like to experiment with a "mushroom stick" (think: *stiff*
joystick with a hemisphere attached to the top) as a foot control
but have more important things calling on my time...  :<