How difficult can it be to control the LED of a webcam?
Not at all, at least if you have a Logitech Quickcam (uvcvideo).
Just install libwebcam (
http://sourceforge.net/projects/libwebcam/) and use the following commands:
uvcdynctrl -i /usr/share/uvcdynctrl/data/046d/logitech.xml
uvcdynctrl -s 'LED1 Mode' 0
#to deactivate the led, or
uvcdynctrl -s 'LED1 Mode' 1
#to activate it
# 2 for blinking
# 3 for auto
use -d videoX to specify the device (default: video0)
# print all controls and possible parameter
uvcdynctrl -c -v
see "man 1 uvcdynctrl" for more infos
It should be easy to use the blinking mode as notification (chats, emails, ...)