[simpits-tech] Small CRTs (Was: Just a quick update.........)

[Cris Harrison]

On 4/13/2012 10:25 AM, Gene Buckle wrote:
> On Thu, 12 Apr 2012, dabigboy at cox.net wrote:
>
>> ---- Gene Buckle<geneb at deltasoft.com>  wrote:
>>> Just be aware that a pc keyboard does not use a diode isolated switch
>>> matrix, so you'll only be able to hold 3 or 4 "keys" down at once before
>>> the keyboard stops responding to inputs.
>> Yep, I'd noticed that. That's why I've only ever considered it for the
>> FMS or another keypad'ish task, where I will probably never be pressing
>> more than one button at a time.
>>
> You can add diodes yourself like so:
> http://www.geneb.org/ematrix.png
>
> This is for the EPIC input matrix, but it would be essentially the same
> schematic for hacking a keyboard matrix.  Once you identify the row&
> column lines it's easy.
>
> Alternately, you could just grab an Arduino and a Centipede Shield and
> skip the whole keyboard mess to begin with. :)
>
> g.
>
>
gene.. I like your position but its a white herring.. On most avionics 
keyboards you cant get an N rollover problem.. with you idea about using 
a matrix, is ok but you need either hardware (with out the arduino, just 
some counters, and a timer) or you do it in software...
did you look at Matt's CDU no room to get N-rollover.. arduino is almost 
plug and play.. + you get the pc's keyboard for  debug and running the pc..
Enjoy the dark side..
Cris H.