Re: Sending Multiple Scattered Logic Level Signals To a Processor

Thanks Denny,
Ya no microcontroller at the transmitting end unfortunately. Yes 4-20 ma
would be a good way to go if the environment was a bit more hostile or I
had a longer run.
Jim


On Mon, Apr 28, 2025 at 12:44 PM Denny Esterline <[email protected]>
wrote:

> Cat 5 cable is about as cheap as any wire you'll find.
> Signal and ground on one pair @ 3.3 v is perfectly reasonable in a
> non-hostile environment, at very low data rates.
> If you have the pins, using them as a pseudo differential pair can add
> some reliability. In concept, software always sets pin B to the
> opposite of pin A. Feed them into a comparator on the receiving side.
> I suppose that presumes a microcontroller on the transmitting end and
> if you have that, there's probably better protocols. (232, 485, CAN,
> etc)
>
> There's also the old standby of 4-20mA current loops. I've seen them
> covering miles in pretty hostile environments.
>
> -Denny
>
>
>
> On Mon, Apr 28, 2025 at 7:38 AM Jim Ruxton <[email protected]> wrote:
> >
> > I have a project where I want to send about 15 logic level sensor outputs
> > scattered around a room approx. 15' x 15 ' to a processor. The processor
> > could be an ESP32 , Pic or Arduino. I'm just wondering how folks would
> > handle this. Would you want to optically isolate at the sensor end? The
> > processor will be just outside that 15 x 15 foot space? I don't expect
> the
> > room to be particularly noisy electrically. Can I get away with just
> > connecting the logic level outputs to an input pin? The logic level
> signal
> > is very slow just an on or off trigger.  I imagine the longest wire
> length
> > would be about 25 feet. thoughts?
> >
> > Jim
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