Main > Main Forum
LPT Switch
(1/34) > >>
Trimoor:
Has anyone looked at the LPT switch interface?
One of the latest project announcements used it for their control.
(Or did you skip over it just because it was in Portuguese?)

It's an extremely cheap interface that allows you to connect 60 inputs over the parallel port without ghosting or bloacking.  60!

It's too bad the drivers are windoze only.

Here is the circuit:



Edit:
Here is a translated link:
Translated
Silver:
Are you sure there is no ghosting?

I've had a quick look and it seems to me that say buttons 1,2 and 6 are held down - then there would be ghosting for button 7? (for example) or am I missing something? (quite possible)
Trimoor:
If you remember the KE series keyboard encoders, some of them use matricies.
Ghosting can be avoided by sequentially scanning the matrix instead of waiting for a button to be pressed--interrupt vs. polling.

From the site: (translated)

--- Quote ---it does not have problem of ghosting (keyboard keys ghost), as in hack of keyboard
--- End quote ---
Here is a translated link:
Translated
brained:
Hey that's pretty interesting. I've found the original site, that guy made a home made cockpit. This site also contains the documentation for building the interface

http://users.skynet.be/plipke/PF50HC/

BYOCP :)
brained:
Ohh I've found out that the drivers are open source, so If some one can port it to DOS that will help a bunch :)

Navigation
Message Index
Next page

Go to full version