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Fluorescent Lights Magically Activates iMac?

Posted by Cliff on from the weird-goings-on-here dept.

bats asks: "In my computer room at home, I have several machines -- and a fluorescent desk lamp. Among my various boxen is an iMac DV (slot loading) circa 1999. Its configured to go into power saving mode, but respond to wake-on-lan packets. The weird thing is this: If I flip on the fluorescent desk lamp, the sleeping iMac will suddenly wake up! This happens with 100% consistency. The desk lamp is plugged into a power strip and into the wall. The iMac is plugged into a UPS and then into the wall. The network switch for the room is near the desk lamp (1-2 feet) but the iMac is some distance away (8-10 feet). My question is: WTF?! How the heck does the iMac know when the light comes on? It seems like it must be some power spike in the AC or noise on the network interface. However, the power strip and the UPS should block an AC spike and the chance of electrical noise in the cat-5 looking like a wake-on-lan packet seem more than miniscule. So again I ask you, dear AskSlashdot reader, WTF?! I await conspiracy theories, pseudo-science, wild rantings, and hopefully, the right answer."

3 of 108 comments (clear)

  1. Does it have IR port? by marat · · Score: 4, Interesting

    Probably it's receiving some nonsence data when you switch on the lamp. Also, UPS might be trying to tell you something via it's COM port connection or whatever. Network interference via switch is also possible. Plug out one by one and check.

    My PC turned on after any phone ring (very disturbing while installing some new hardware :( ) though they was not 'Wake up on ring' option in BIOS. Turned out that 'Wake up on LAN' also works as 'Wake up on ring'.

    BTW does you mac have external modem? Probably your modem tells RING each time you turn on the lamp. Easy to check with any terminal program.

  2. Mobiles phones by cowbutt · · Score: 4, Interesting
    I woke up early one morning to the sound of my electronic metronome going tick-tick-tick-tock quite loudly. My first thought was that I'd somehow managed to leave it on before going to bed and sleeping right through it. When I checked, I found that my old Nokia 6150 was charging right next to it and the aerial was pointing right at it.

    My guess is that one of the periodic cell checkin transmissions induced enough of a current in the on/off circuit that the metronome decided to switch on. Spooky!

    --

  3. Your UPS is sending a heads up ... by kousik · · Score: 4, Interesting

    Is your UPS connected to the network
    so that it can inform the machines
    when there is a change of status of
    power line? Maybe when the light is
    turned on, the power surge makes UPS
    send a packet to your network? Just
    guessing.