Active your screen or PC via sonar. This can be done if the PC has some speakers and a microphone attached. No additional hardware needed.
I haven't tried this one myself yet but its worth a look
http://stevetarzia.com/sonar/
Cheap (nearly for free) PC control
Cheap (nearly for free) PC control
Yep and the systems there is always someone at the pc, because there is noise in the living room
Alexander
Alexander
Cheap (nearly for free) PC control
The ping have a frequency of > 20KHz so there isn't that much trouble. Also you can modulatie the ping which will cancel out all false hits. Same as for IR. Your remote will not work if the sun is shinning on the receiver unless you modulate the signal.