[sdiy] usb keyboard matrix hack

[Dave Krooshof]

>>  How would you suggest throwing the voltage to 0 when the switch is off?
>>
>A 10k resistor to ground (known as a pull down resistor).
>
I tried that, but now the keyboard says "89+" to the computer
when I want it to say "7".

I only have one connection for testing. When I switch everything
on, the keyboard repeats "777777777777".

The keyboard has a fas sequencer. It checks row by row
with this sequencer, and responds to connections to certain
pins to figure out in which column the pressed key is.

 From the diagram I drew of the matrix, I can see the
circuit responds to slow, thus skipping the 7.
8, 9 and + are the next columns. So using the resistor
isn't speedy enough! or the SN74LS08N is too slow.


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groets,

_          >^v<        _

website http://www.dendriet.nl