IT can be done with one parallel port or two serial ports. Parallel ports are
quicker, but require some fancy programming. Serial ports are easier, since you
can hold CTS, DSR, etc high for any length of time. Pick up a book on serial port
programming; it'll explain how to do it. I don't know enough about Linux to tell
you if Linux allows direct hardware control, though.
Serial ports may give you enough current to drive a small, IC-type relay, though I
can't guarantee that that won't toast your ports. I'd experiment with a $20
add-on card, not the mobo ports.
I've done this sort of thing under DOS - since it was so ignorant of the internals
of the computer, some things were actually easier.
Yan
> On Sun, 11 Oct 1998 20:19:59 -0400, G. Georgiev did spake:
> > The problem is how to connect this in/out relays to the computer?
> >- is there some not too expensive way to do it? Two input sensors (relays)
> >and three - four output relays shall be enough.
> You could probably do it with the parallel port actually, relatively
> easy (with a basic bit of hardware & software knowledge.) With the
> parallel port you've got a basic 8-line I/O?
> I can't believe there's not something on the net that gives
> instructions out on how to do this sort of thing!
> One potential complication is that you'd almost certainly have to
> give whatever circuitry you'd have attached to the parallel port it's
> own power.
> Ta-ra,
> Julie.
> --
> To reply by e-mail use the supplied Reply-To: address from the message headers
> (your software should do this automatically). There is no need to edit that
> address, it is correct as it is. Alternatively, if that address gives you
> problems, you can instead use my first name as the user part of the address.
by