[laptop-accessibility] sdcard slot GPIO

[Jim Gettys]

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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-- 
Jim Gettys
One Laptop Per Child