RS-422 (single TX, multiple RX) or RS-485 (multiple TX & RX).
Balanced lines are much better than RS-232 though I have used RS-232 for decades. Other balanced line technologies could work. Network technologies clearly work and they are balanced lines. CAT 5 or 6 cables are pretty cheap. Balanced lines generally radiate less and are less susceptible to external interference.
Charles AE5EW
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--- In Electronics_101@..., John Woolsey <jwoolsey@...> wrote:
I am working on my project. Although I want to make a USB I/O device, I
have realized I just don't have the confidence for it. So I have decided
to buy a USB I/O device and get on with things. I will come back to this
later once I am done more of the project.
So I am trying to find Criteria for the USB device. At the current time
my list is:
Must have Linux drivers (accessible from Java).
Must have Pulse Width Modulation (probably two per device).
Reversible ports would be good Input or output on each pin.
Should have at least 16 ports.
It would be nice if you could time ports to flip on for a short period
(to not burn out solenoids).
It would be used for:
Turning on and off lights. (I think 9V bulbs. Might be 12V).
Sense switches closing.
Firing Solenoids at 48V for short periods so they don't burn out
Holding Solenoids via PWM to keep them fired but not burn them out.
For 48V I am looking to get a power supply and then use a power transistor.
I have looked over the internet and I have found tons of boards that
fit. But I have no experience on which one to choose or what is the
"best board". I am in Toronto ON Can so if there is a supplier there
that would be great.
So advice me please. Any suggestions would be helpful.
thanks
John
