[sdiy] Substitute for pin matrixes?

[Tony Clark]

On Sun, Jan 24, 2010 at 11:36 PM, John Mahoney <jmahoney at gate.net> wrote:
> At 09:51 PM 1/24/2010, Tony Clark wrote:
>
>> Maybe I'm not quite envisioning this correctly, but you can simplify
>> this down to just a single layer of PCB with a hole (smaller than the
>> size of the ball)  that has two plated half-rings around the edge.
>> When you drop your ball in, it will connect the one half to the other.
>
> That's like what I was trying to describe in one of my magnet-related
> schemes -- pads made of 2 half circles. I don't see how you can do a
> row/column matrix with a single-sided PCB, though, which is why I spec'd a
> double-sided board. One of us isn't envisioning it correctly, for sure. <G>

Jumpers, DUH!  ;P

I was referring to the number of stacked layers, not so much that the
PCB needed to be single-sided!  :)

> As cool as the ball bearings would look, I wonder if they would make for
> reliable contacts. Also, they could easily be knocked out of position, which
> provides some unusual performance possibilities but isn't the kind of UI
> that I'm looking for. That's why I suggested magnets -- personal bias at
> work.

A ring magnet glued to the underside of the afore mentioned board
would work to hold the ball bearings in place.

I too like the idea of magnets, I've been using reed switches for
years and am always looking for new ways to use them!

Cheers,

Tony

-- 

Tony Clark
Great Lakes Modular
www.greatlakesmodular.com
Design, Engineering, and Manufacturing Services