I am not aware of any libraries in CPAN that give you this functionality, but this might be good excuse to learn XS. If you can figure out how to twiddle the LEDs in C/C++, then just wrap it up with XS so you can call into it with Perl. From a short term practicality standpoint this would probably be a largely futile effort, but from a scholarly point of view, just learning XS would make it worth your troubles.