Okay I know this topic has been covered in a few ways but I haven't seen any with remotely controlled web servers. My question is... Is it possible to use a web server to control an arduino on a client computer? My idea includes opening and closing a valve connected to an arduino when a client selects a certain valve to open. If so how will the server running php most likey communicate with the usb on the computer? Also if possible I would like to avoid using an Ethernet shield if possible.
If so how will the server running php most likey communicate with the usb on the computer?
The arduino USB connection is seen as a serial port by the computer to which it is attached. Thus you have your application running in conjunction with the web server communicate with the arduino via the serial port.
zoomkat:
The arduino USB connection is seen as a serial port by the computer to which it is attached. Thus you have your application running in conjunction with the web server communicate with the arduino via the serial port.
This is true if the drivers are installed on the PC to make the USB port look like a COM port. I know the drivers are available for Windows, don't know about other applications.
To the OP, if you have a computer running its web server, you can write code that will send commands to the Arduino based upon what a user does with the web page. This is pretty easy actually, and there are many ways to do it. As zoomkat said, you can just talk to the Arduino via a computers COM port.