I have attempted serial comm via PHP to Arduono using a WAMP install on a PC...
serial comms seemed to work only one way.. and I was told that this was a PC issue, but on MAC/Linux, PHP serial comm works two ways without issue.
I have previously set up a RPi with Apache, MySQL and PHP...... (for some added support/features in an MQTT set-up/project)
I have never attempted to use PHP serial communication when things were on a Pi.
I will have an Arduino connected to the RPi.....
The RPi will have a webpage served up that I write.
What I would like to happen is upon clicking a link/hotspot in the hosted webpage it to send some serial data upon $_POST to the connected Arduino via PHP... have the webpage sit in an 'idle' state... and when the Arduino is done doing its task(s).. send out a serial message back to the RPi/PHP script.. and then change the display state/view of the hosted webpage.. (waiting for another 'user interaction' so to speak)
Is 2-way serial communication possible with PHP when running on an RPi3?