How to control you hardware from a webpage

jon_newcomb wrote on Friday, December 10, 2010:

….using FreeRTOS, Ajax, prototype.js, HTTP POST and a static filesystem

Hello folks,
A while back I searched for AJAX under FreeRTOS and didn’t find anything, so I thought I’d start a thread to share with the community what I have so far…
I have started a project that uses AJAX calls to send and receive JSON data to update a web page / control hardware. Uses HTTP Post
I make use of the FreeRTOS / prototype.js / Protosockets / uIP 1.0 / AT91SAM7X
PHP is emulated on the target.

If you are interested in this sort of thing… Consider joining me to work on the device it is going into…

There is no external filesystem used. All the JavaScript libraries are compressed – and using content encoding in the response header, the web browser decompresses them on the fly. It saves lots space!
You can see all the types of HTTP Headers I have used… cache connection and so on…

So far… this a hosted version of what I have done – and got working in FreeRTOS / uIP

The zip file is the uIP webserver and associated html files

I use XAMPP to develop the HTML, then when I’m happy I use of and then hardcode the PHP support into the target – so the supplied PHP files are for your test server, not your target.

I can’t support the project, but if you are trying something similar, consider it as a push in the right direction. Check back from time to time as depending on feedback, I wish to update the files in the links.
It’s not a whole project as such, just the directories where I have made modifications.

As uIP works within its own thread, you must be careful when linking events generated within uIP to your application. Critical sections can be used for reading and writing to variables shared across tasks…
The uip_post.c  is used as the link between uIP and your FreeRTOS application code

uIP also has relevant discussions, search for AJAX.


davedoors wrote on Tuesday, December 14, 2010:

Very nice. Did you make many changes to uIP itself? I don’t see uip.c in the archive. Could you add it?

jon_newcomb wrote on Thursday, December 16, 2010:

Dave, It does not change uIP.c 1.0 - as its all an extension of the webserver application.
Its the webserver application makes calls to uip_post.c where the handlers are located. That goes with application code… (that’s why there is a lots of undefined function calls…)

Anyway, I have updated the webserver and zip file to the latest release I have, see above links.
Switching development to other things for now…

If anyone else is reading and likes what they see… please consider joining me where I work - and take part in its development…

jon_newcomb wrote on Thursday, December 16, 2010:

Forgot to mention, the page now supports coloured tags that change from red to green depending on state…
click of checkboxes updates LEDs.
You can look at the hosted demo above using Firefox with the Firebug plugin to see the underlying AJAX calls