Serial Communication with Arduino over the Net

Projects Networking, Protocols, and Devices
1

Hello dear Arduino Fellows,

I got an project which is a bit more complex than the usual approach.
The server side is an linux server with the usual lamp stack and I enter data via an webbrowser on an client over html/php forms and store these in the Servers MySQL DB for persistence as well.
Now, I need to enter different data in these forms and send them aswell to an Arduino in an low latency way.
As I only got the usual cheap enc28j60 ethernet shield, I doubt that this would work out reliably - as well as "pulling data" from the Server in form of reloading some webpage every 1s should be the wrong way to do it.
To solve that problem, I thought of using an raspberry pi and connect the Arduino to it via serial / usb so that the rpi could do the data connection and send the information to the Arduino.

But now the big question: How to get the Raspberry Pi to connect to the Server and get information from there in an sort of "twitterish way", so that the server pushes information down to the rpi, instead of pulling data?
I think that should be the better way to do it - or do I miss something out?
Could somebody give me an hint to solve that "connection gap" or has anyone an better ideA?

Thanks a lot!

2

How to get the Raspberry Pi to connect to the Server

And what part of this is related to the Arduino?

If you are using PHP as part of a LAMP stack, get the PHP serial class, and add it to the PHP package. Whenever a PHP script runs to update the database, it can push data to the Arduino.

Of course, you may need to modify the Arduino to prevent resetting each time PHP opens the serial port.

3

PaulS:

How to get the Raspberry Pi to connect to the Server

And what part of this is related to the Arduino?

If you are using PHP as part of a LAMP stack, get the PHP serial class, and add it to the PHP package. Whenever a PHP script runs to update the database, it can push data to the Arduino.

Of course, you may need to modify the Arduino to prevent resetting each time PHP opens the serial port.

Thanks for the answer Paul! (nice to speak to you again, we have been in contact some years ago for an older project of mine, the Ticket Scanner, you recall? ;))

Well, problem is, the lamp stack sits in a virtual server some hundered kilometers away, so I won't be able to connect the serial port directly to the Arduino.