Re: Sending Multiple Scattered Logic Level Signals To a Processor

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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