Re: Sending Multiple Scattered Logic Level Signals To a Processor

When I first started using ESP devices I optoisolated everything but it 
soon became apparent that that was overkill. I've had ESP devices 
directly attached to sensors, etc. in very hostile environments, 
greenhouses, for years with no trouble. Some of the display screens, 
especially the OLED displays, are no longer readable but the devices 
still work. Most send data by MQTT, some flip relays through a driver 
transistor.

For communication I like MQTT because every device can both report and 
monitor.

Allen Mulvey

On 4/28/2025 10:38 AM, Jim Ruxton 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