Re: [Emc-users] OT: 'touch' screen

[Chris A. <alb...@gm...>]

A cheaper way to sense position is the scanners used in store checkout
systems.  There is an octagon shape mirror that spins and a laster is aimed
at the mirror.   Then you need an IR photodiode.   It's cheaper because you
can use a one-pixel sensor.

On Sat, Dec 1, 2018 at 9:44 AM Gene Heskett <ghe...@sh...> wrote:

> On Saturday 01 December 2018 10:17:29 Roland Jollivet wrote:
>
> > I've been thinking about how to implement a touch screen of sorts on a
> > 19" monitor. The TFT displays are too expensive for their size.
> >
> > Then I came across this;
> > https://www.youtube.com/watch?v=2aOYc_GKTHQ
> >
> > Very interesting, and with more scanners and LED's it could be very
> > usable! Next is to explore how easy it is to drive them..
> >
> With the ccd bars from a fairly modern scanner, you would have both in a
> unit but working with white light, not ir, and since both are in the
> same bar, one could theoreticly multiplex them for even better accuracy.
> But even the bars out of my brother mfc-j6920dw, would only give you 11"
> of active area, and I'm sure the white light would be a distraction in
> use, so one would have to make 2 bars of ir emitters, which could be
> made longer increasing the size of the working field at the expense of
> poor accuracy in the corners. 2 ccd bars end to end would solve that,
> giving 22" or more of scanable area vertically. How much $ would you
> have in getting those parts from brother?
>
>
> --
> Cheers, Gene Heskett
> --
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> Genes Web page <http://geneslinuxbox.net:6309/gene>
>
>
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-- 

Chris Albertson
Redondo Beach, California