I am working on a project, where i will be able to control ouputs of Arduino over HTTP, but thing is that i don´t know the IP adresses of the Arduinos and routers and firewall will prevent me from sending commands directly to Arduino.
So i need the Arduino to initiate the connection to the web server, but i don´t want the Arduino to poll the web server every 1 second and i will reduce delay in the commands to an absolute minimum.
My idear is to initiate the connection from the Arduino to the webserver, but wait to send the respond to the Arduino, until just before the request times out, leaving the timeout settings as window to send commands to Arduino almost zero delay.
I don´t know what the timeout is, but imagine it could reduce poll request to every 30 sec or so.
I would like to do it HTML and PHP.
Anybody that can help me do that?