Re: Need help with parallel port input design-follow up question

Lloyd:

I'm nearly clueless on this stuff. Am I right in assuming that a
Motorola MC14069UB is the same as the 4069 you refered to? (It's
what Google found). If so, am I right in assuming that VDD should be
set at 5 volts and VSS as ground? Can I use the PC 5 volt supply?
(otherwise, I've got to figure out how to use the Vregulator,
probably no big deal though). Does the 10K resistor pack go to
ground? And if so, from the input side or the output side? The
diagram on the spec sheet also shows a capacitor on the output side
to ground. Is this required (and if so, what's a good value)? Sorry
to sound so lame, but haven't done this before.

Regards,
Jeff


--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Lloyd Leung" <lloyd@l...>
wrote:

> Jeff,
>
> I think an opto-isolator is overkill. I would suggest using a 7404

or 4069

> hex inverter, to accomplish the same thing. Both are very cheap.

Download

> the PDF (google, "7404 pdf" or "4069 pdf") and see what pins are

what.

> You'll figure it out.
>
> Use a 7805 voltage regulator to get the power from the 12V source

down to 5V

> as well. And to clean up the power, place a 10uF cap across the

output and

> ground after the 7805.
>
> A resistor network of 10k ohm will help pull up the current to 5V

as well.

>
> Depending on how quickly you want this board, I would recommend Dean
> Coullard's break out board. It's well made and clean, and simple.
> http://members.shaw.ca/axxus/db1v20.htm . I asked him last week,

he was out

> of stock, but will be getting some in soon.
>
>
> I bought one, and am very happy with it. It made things a lot

easier to

> wire up.
>
>
> Cheers.
> Lloyd,
> Toronto
>
>
>
> -----Original Message-----
> From: washcomp [mailto:jeff@w...]
> Sent: September 15, 2003 4:50 PM
> To: CAD_CAM_EDM_DRO@yahoogroups.com
> Subject: Need help with parallel port input design
>
> I'd like to provide opto-isolation to the 5(?) input pins on a
> parallel port used to monitor limit switches. I understand that

I'll

> also have to provide some resistors? What's the easiest way to do
> this? I looked at the Digikey catalog and they offer about 4

million

> opto-isolators of all types, but I'm kinda clueless about which to
> use or an actual circuit to make use of the right one. Any help
> would be appreciated. I've bought an 8 port parallel relay board

and

> figure I can retrofit this to the input pins (they are currently

not

> connected on the relay board, but it has a 12v DC supply built on).
>
> Thanks and regards,
> Jeff