How hard would it be to add an rrdgraph for modem signal strength?

[Tuckie]

I'm interested in some how adapting this:http://forums.cacti.net/viewtopic.php?t=8688 idea for my sb5100, and I'm wondering how hard it would be to parse the signaldata.html file (from what I can tell, perl isn't installed) and generate data for rrdgraph.  I have no idea where to start and any tips/guidance/help would be appreciated.

[mastrboy]

even if perl is not installed, PHP is installed and can do almost everything perl can (not sure what modules are installed on PFsense though).

So if there is a perl script for this, look at the code and try to convert it to PHP (some help can be found here: http://www.cs.wcupa.edu/rkline/perl2php/)