[laptop-accessibility] sdcard slot GPIO

[linaccess at yokoy.de]

hello Jim,

there are big improvements in speechrecognition and I won't block the mic input. Anyway, we could get 5 ore more I/O through the cardreader. That could be interesting for other projects, too. In addition the audio A/D is more cpu hungry and slower.
I have read about the idea using the condensor power of the mic jack. How do you switch this power? echo foo /proc/acpi/bar or something?

yokoy


On Fri, 08 Jun 2007 18:38:08 -0400
Jim Gettys <jg at laptop.org> wrote:

> Even cheaper, if you don't need microphone in: just hook a switch up to
> the microphone input (through a resistor), and measure the voltage.
> 
> The machine has the ability to use the microphone input as an A/D
> converter, and with the bias voltage for microphones, you don't even
> have to have a voltage source.
>                               - Jim
> 
> 
> On Sat, 2007-06-09 at 00:19 +0200, linaccess at yokoy.de wrote:
> > hi,
> > the sdcard slots intended purpose is to use it with sdcards, shure. Would it be possible to use some pins as GPIO (generic purpose in out). If so, it would be easy to build very cheap hardware, for example a morse pushbutton for morseall (http://morseall.org/). With this it would be possible to control the machine with one finger.
> > 
> > The idea using the sdcard slot for GPIOs is reverse. On Linksys boards with openwrt you could use the GPIOs to implement a cardreader. Why not vice versa using the sdcard slot for gereral purpose I/O?
> > 
> > yokoy
> > 
> > _______________________________________________
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> > accessibility at lists.laptop.org
> > http://lists.laptop.org/listinfo/accessibility
> -- 
> Jim Gettys
> One Laptop Per Child
> 
> 
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