Your flourescent light operates from a phased AC signal - it's what keeps the light lit. When you turn it off and on, you actually cause a major RF "blip", and it can wreak havok with computers, especially if the lamp is located in parallel or perpendicular to the external peripherals.
F'r Instance:
I have a flourescent black light mounted in the keyboard hutch, above the keyboad and just far enough back that you can't actually see the lamp, but the black light "washes" over the keyboard, and the shirt of the person typing. It's a really cool effect. But with one drawback: When you turn the lamp on or off during normal computer operations, either the keyboard or the mouse (usually the mouse, for some reason) stops behaving properly - or at all, in some cases.
I discovered that this is due largely to the frequencies involved with the mouse (in reality it is a polled device: your internal windoze/linux drivers are what make it event-driven). When the lamp is turned on (or off, for that matter), it produces a noisy (frequency-wise) "burst", which tends to affect some digital equipment, in semi-random fashion. And the kicker: it doesn't always happen, it doesn't always freak out the peripherals. I had to "camp out" at the keyboard with my signal tracer/freq meter trying to figure out the same thing.
But: how do I/we avoid it?
I discovered the use of aluminum foil at the correct junctures (along your cabling) isolates the "antenna" effect. Also finding the electronics in the lamp and re-aligning them to 45° with your peripheral lines (meaning you have to keep them neat and tidy, not sprawling all over creation, like we all do...) will keep occurances down. Since I can't seem to keep my cables neat and tidy, I used aluminum foil (the stuff you get at the store) to isolate the cabling from the back of the PC to my desk, and discovered that it (almost) eradicated this effect.
Hope this helps,
-- The Lurking LongFist |
