I have controlled a big led screen using PHP remotely. It is almost the same problem, the way I managed this task is launching a system monitor that is monitoring certain files for changes (in your case for example, angles to update the camera) and this monitor "eats" this files, so php knows if the last instruction is applied.
Problems:
-Apache must allow "interactive" process (apache configuration)
-The monitor should be singleton (just one instance to avoid port sharing issues)
-The monitor should "monitor" files in such an elegant way like the filesystemMonitor object in c# to keep polling out your system
The monitor resides in the www folder (php just 'exec' init_monitor.cmd then edit the bin/screen files):
http://screencast.com/t/Mjc3MTEzODk
The files generated by php contains a special format for each line of the lcd screen, also the delay to send the next one (I use .temp extension files to work first from php because data is extracted from db with some delays and I don't want the monitor opening my files until I copy the final file with .screen extension):
http://screencast.com/t/MDcxYzRh
And voilá, a cute monitor icon with a little eyecandy 
(it blinks a little while sending a new screen):
