[sdiy] Duplex LED controller, was iPod click wheel

[harrybissell]

If I had to take a guess, I'd say that they were using the LEDs and a
matrix with
one (or more) LEDs on and the rest as detectors. Who knows how fast they
may
be multiplexing them.  They can probably detect the backscatter directly
through
the finger... If you press an LED to your finger, it will glow (red) like
ET, na ???

The LEDs would all be at the same relative temperature with fast
multiplexing, so
that would eliminate the temperature problem.

If you watch the movie CAREFULLY you'll see that the LEDs light up as rows
at power
up. I'd guess that they light one row at a time in the X axis, and look at
the adjacent
rows for a detection. Then they could scan the Y axis in the same way. That
would give
you an X,Y coordinate for each finger or spiral penis you apply to the
array.

VERY cool idea. Let's clone it.  Only problem is 'what do you control with
the output'?

H^) harry

Metrophage wrote:

> --- Sumanth Peddamatham <peddamat at gmail.com> wrote:
>
> > If you are interested in an alternate, but equally cool haptic
> > interface implementation, visit:
> > http://mrl.nyu.edu/~jhan/ledtouch/index.html
> >
> > I am trying to duplicate Jeff's effort using a few LEDs and a micro.
>
> That appears to be very interesting to me! Thanks for the link,
> Sumanth. I had no idea at all that LEDs also act like photodiodes. Also
> I have never used photodiodes so I am not even familiar with their use.
> Doing some web searching on this is slow going. One page I just found
> mentions duplex LEDs for emitting and detecting, but it sounds like
> they are talking about on fiber with a separate LED on either end.
> < http://www.fiber-optics.info/articles/detector.htm >
>  How does this work using an array which are all doing both functions?
> I wonder if there is a current change when I put my fingers over LEDs.
> Also I wonder what sort of LEDs work best for this sort of application.
>
> Time for us to clone the Technos Acxel!
> CJ
>
>
> __________________________________
> Yahoo! Mail - PC Magazine Editors' Choice 2005
> http://mail.yahoo.com