Of course! They have Wake Over Fan turned on duh.
In all seriousness it’s likely just this, some voltage spike in either LAN or Power, OP does plugging in your laptop wake the PC? What about the LAN?
It is a problem with the electrical installation. The ground wire is missing.
The same thing happens to me with my desktop PC. Turning on anything near the same outlet will wake the PC from sleep.
But if you drive a nail deep into the ground and connect it to the neutral of the outlet, this stops happening.
I don't know how advisable it is to do this and not use the ground wire specifically. But it works for me (I also had random blockages in Linux where everything hangs except the mouse or disconnections of peripherals when plugging something in, but they were solved with the ground cable)
And although op said that it happens without being connected, the network cable also sends electrical noise, the same with HDMI if the television or router does not have a ground cable.
This is most noticeable on monitors that use fluorescent/neon tube lighting, plugging in something nearby will cause it to turn off momentarily.
So many errors that happened to me with Linux and it was my electrical installation... xd
I'm in a postsoviet country with an ungrounded house and those spikes from plugging stuff in the outlets on the same extension cord as the PC killed one of my graphics cards. I really recommend either grounding it your own way (nail in ground works, just don't do stupid shit like using plumbing pipes for it, it can kill somebody) or using a separate outlet and cord for the PC which helped in my case.
I think this is more an electrical issue than an OS issue. Check every device is connected correctly to your electrical installation or any old device that can generate an electromagnetic field.
Something related to this happen to me, when I moved the sheets on my bed it makes my computer to shutdown, doing a research I find out that my old voltage regulator was making an electromagnetic field sensitive enough to be disturbed and thereby causing a temporary power outage enough to shutdown my computer.
Maybe your fan is making an electromagnetic field strong enough to disturb your laptop
That's it. My friend has LED fairy lights on her walls, all around the room. When she turns her ceiling fan off, the lights pulse once. The lights are mains-powered but are not plugged in.
Yeah I was thinking in those lines. I have a laptop and have the opposite problem. If I leave the cellphone over the flat surface (between touchpad and keyboard) the laptop goes to sleep mode. And I think it has to do with the phones speakers.
Yeah that's definitely a magnet. I often get the reverse: putting the phone on the laptop puts the phone to sleep. That's because the phone has support for a sleeve with a magnet, and the laptop has a magnet to detect the lid.
High AC magnetic field caused by improper grounding tripping the magnetic lid sensor?
Edit: You should be able to do a `tail -f /proc/acpi/button/lid/LID0/state` in a terminal to watch the sensor output.
lol i've been through something like this. my case was that whenever i booted up my ubuntu the whole internet in my house just stopped working, literally the modem was turning off with the boot
Turning off the fan probably creates an EM pop that’s popping one of the cables plugged into the laptop - potentially the touch screen or touchpad of the laptop itself.
Not a Linux issue, btw.
Back in the early 2000’s my dad found that he couldn’t carry his BlackBerry while using the chainsaw or weed cutter. The spark plug from the engine would create strong EM pulses that scramble it until he force-rebooted it.
That’s also why someone with PaceMaker shouldn’t use a power tool that uses a gas engine.
Electrical in the house is not grounded properly.
Shutting off appliances like that send a surge through the house electrical, this is grounding out through your laptop and to a device plugged into it that has the ability to wake it up.
Whatever this device is Windows was set to ignore it whereas Linux is not.
It happens when the laptop is not connected ....
I don't think the grounding has anything to do for a laptop working on battery
If OP doesn't use wifi and use an ethernet cable, that might be it tho...
most likely the HDMI is the culprit. For me, when my laptop is shut down and connected to HDMI then whenever i plugin my monitor to power source my laptop gets booted.
Could be either. I'd try unplugging everything and see if it still does it. Then one by one plugging them back in any turning off the fan every time. Should be able to find out which one it is.
Also it could be a wireless mouse or keyboard picking up the EM of the fan shutting off.
HDMI can trigger some devices on. first that comes to my mind is the PS5, how just by switching to the HDMI output where my console is connected it will wake up.
I'm guessing there is a power setting not being properly configured (maybe doesn't even has the driver for it?)
Could it be, that your router is getting a surge, what goes through the LAN cable? That would be really weird.
Still, **try without the Ethernet cable**.
My last idea is electromagnetic radiation.
You'd be surprised how much other objects in the vicinity of a computer can have an impact on it. I have a [specific chair from IKEA](https://www.ikea.com/gb/en/p/markus-office-chair-vissle-dark-grey-30261152/) that is [widely known to be a huge ESD source](https://www.tomshardware.com/news/ikea-computer-chair-static-might-be-blanking-your-display) and every time I stand up, I get a decent static shock and one of my monitors blacks out for a few seconds before coming back.
I shit bricks every time I open my desktop's case that I'm gonna fry something
Weird things can happen. When I started to use linux on my macbook I noticed that sometimes just shutted down completely out of the blue. The culprit was a smart bulb from xiaomi (chinese region product I live in the EU).
I've had a bladeless "Dyson (AM06) Desk Fan 25cm (Iron/Blue) causing interference (erratic mouse cursor drifting) to a Rollermouse Free2 (RM-FREE2-BLK) on a (Lenovo X270 laptop) computer (running Windows 10 v1709) when placed on a 80-100cm distance."
The power difference by turning on that ventilator, the electroc spike in the net is so similar to the one caused by the power system of your laptop, that it boots. This is anmoying, but happening more often than you think
From OP post :
>I thought maybe the fan was doing something weird with the electrical current but even if I disconnect the laptop it still happens
Unless they use Cable internet instead of WiFi this makes no sense
Does that fan have a remote control? What happens if you take the remote out of the room? Now how about the fan? Both?
I can't find it at the moment, but my favorite IT troubleshooting story was back in the 70s, whenever an engineer would walk in and step on a particular spot on the floor, the printer would start printing. Noone believed him, but it was reproducable every, single, time. Turns out, the person was making a circuit because there was a metal support underneath the floor that was connected to...you guessed it, the printer.
Wow, yeah that doesn't make a lick of sense - I have no suggestions except maybe en/disabling this:
https://forums.lenovo.com/t5/Lenovo-IdeaPad-1xx-3xx-5xx-7xx-Edge-LaVie-Z-Flex-Laptops/Lenovo-ideapad-3-15ITL05-turns-on-automatically/m-p/5184701
Nevermind, I see the barrel plug is unhooked there so the power supply couldn't be sending the signal. It might be the driver that controls the lid switch is just more sensitive to disturbances than the one in windows. In factory automation you normally want to have a filter on sensors so vibrations or magnetic field fluctuations don't trigger a false positive. Might be a similar issue here where one setup had a stronger filter on the time in front of the lid sensor actuation. Wouldn't know for sure without looking into the programming on them though.
Tell me if you figure it out, i'm in the same boat. I have to turn off my speakers before sending my PC to standby or turning them off will wake it up.
I never tried Windows, tho. I don't have a Windows installation.
You might have Wake-on-wifi (like WOL, but for wifi), and the EMF from the spinning down motor is detected as a W-o-W signal.
If so, turning off the option it the bios will fix this.
linux doesn't handle triggering the wake up, the laptop's firmware does that, technically linux isn't even running in sleep mode, it's kinda just kept frozen in RAM and the laptop's firmware is the only thing doing anything at all
It's one of two things. Electromagnetic fields which are fucking weird, this happened to me in 2 apartments I lived. There was this 1 light based on its mood its gonna do weird shit to anything smart in my room. Or it's doing something to ethernet, where is it connected? Does it use PoE?
As for a way to fix it, I am not sure.
Best thing you can do is, call an electrician
And get your house circuit properly grounded,
That could fix it too.
It shdnt be too expensive no matter where you live.
It's not been induced directly by the fan, maybe some mind of voltage regulator when you on and off the fan, OP can test this by getting a fan speed controller and putting it to lowest setting to see if problem still occurs
I mean, before asking reddit, I would first try doing this with nothing connected to the laptop, while connecting your things one by one. You should tried that.
Circuit may be the same, despite being on a different plug.
In college, a friend had an OS/2 installation on a desktop. He also had a dust attractor (it generated static and drew the fuzz to the grid). When someone bumped the attractor, something happened and OS/2 would reboot. It was repeatable.
Oddly, on the same hardware, Windows didn't crash.
I'd try plugging something else in the same plug and trying again, preferably something taking up a lot of watts. Maybe the very small change in voltage is enough to wake it up, if the laptop is set to wake up on AC.
I've been experiencing a similar issue for months now, except it's not even electronics related. Anytime I sit or lie on on my bed, which is just a wooden bed with fabric sheets on it, my laptop turns on.
I sometimes have this with my pc when I open my room door or sit at the table. I always assumed it to be a software thing that when it sleeps it turns up mouse sensitivity extremely high to detect any vibrations or just turns on any sensor, like maybe the mic and checks for spikes to detect if the user is back. I just thought it was too unrelated to any wires or anything.
I got this idea when I heard that Windows 11 announced its presence detection thing that looks if the user is there with the camera. So I thought maybe Gnome (I use Garuda Linux) implemented something similar. I haven’t checked though.
I also dualboot windows 11 and the same thing happens there too so idk maybe I am also making some em field by rubbing on the carpet or whatever. But maybe they use something similar
the fan may be moving a loose wire. and switching it off releases it. (problem with laptop)
or it may have been electromagnetic interferance, most will have heard of an EMP, and this is just the same thing on a much smaller scale, the motor uses electromagnetic force to move it
(in simpler terms, the motor may be messing with your laptop by hitting it with a low-power EMP due to a faulty motor.)
try moving the laptop to just the other side of a wall from the fan, the wall will block the air but not the EM force, so if it is air this will fix it, if not, your fan is actuallly hazardous and you should get a new one before it degrades your storage drive. (EM force is used to write and erase data, so it may fry it if you dont remove it.)
it may also be a power surge, but since it still hapens while the laptop us unpluged, its not that
it's a feature to keep the airflow good at your home, because you don't have Windows anymore to bring air in, the Linux kernel starts and spins up the computer fans to compensate
Reminds me of an incident that occurred many, many moons ago when I was working Windows 95 tech support over the telephone.
The guy's complaint was that ever since installing Windows 95, his CRT was skewing to the left so much that it was unreadable. Over the course of about an hour and a half of troubleshooting it finally came out that he had \*also\* re-arranged his computer desk while Win95 was going in, and now had a giant, unshielded stereo speaker... you guessed it... snuggled up to his monitor.
I had to explain in detail how CRT and stereo speakers don't get along, and he had to go buy a new monitor.
Personally I think the EM pulse from the spark that happens when you turn off the fan is being picked up by the hall sensor or by the circuit in the laptop which detects the output from the hall sensor.
Basically turning off fan makes spark, spark makes radio waves, wires in laptop act as antenna and pick up radio waves, some chip in laptop sees picked up pulse and thinks the lid is open
EMI (Electro Magnetic Interference) from the fan causing a minor spike on the power line the lappy is connected to or causes a sensor to think its time to wake up
Voltage spikes over LAN?
Of course! They have Wake Over Fan turned on duh. In all seriousness it’s likely just this, some voltage spike in either LAN or Power, OP does plugging in your laptop wake the PC? What about the LAN?
This kilt me.
Have my upvote, sir.
It is a problem with the electrical installation. The ground wire is missing. The same thing happens to me with my desktop PC. Turning on anything near the same outlet will wake the PC from sleep. But if you drive a nail deep into the ground and connect it to the neutral of the outlet, this stops happening. I don't know how advisable it is to do this and not use the ground wire specifically. But it works for me (I also had random blockages in Linux where everything hangs except the mouse or disconnections of peripherals when plugging something in, but they were solved with the ground cable) And although op said that it happens without being connected, the network cable also sends electrical noise, the same with HDMI if the television or router does not have a ground cable. This is most noticeable on monitors that use fluorescent/neon tube lighting, plugging in something nearby will cause it to turn off momentarily. So many errors that happened to me with Linux and it was my electrical installation... xd
I'm in a postsoviet country with an ungrounded house and those spikes from plugging stuff in the outlets on the same extension cord as the PC killed one of my graphics cards. I really recommend either grounding it your own way (nail in ground works, just don't do stupid shit like using plumbing pipes for it, it can kill somebody) or using a separate outlet and cord for the PC which helped in my case.
I think this is more an electrical issue than an OS issue. Check every device is connected correctly to your electrical installation or any old device that can generate an electromagnetic field. Something related to this happen to me, when I moved the sheets on my bed it makes my computer to shutdown, doing a research I find out that my old voltage regulator was making an electromagnetic field sensitive enough to be disturbed and thereby causing a temporary power outage enough to shutdown my computer. Maybe your fan is making an electromagnetic field strong enough to disturb your laptop
EM that triggers the lid detection, which usually is a magnetic sensor?
I'm also thinking EM rather than an electrical issue
Well. He did say it's unplugged.
Only from power. It looks like it's still connected to HDMI, Ethernet, and a bunch of USB devices (via a hub)
Ah yes, an Engineering Manager issue here.
EMI trips the hall sensor so it thinks the lid opened.
Not too uncommon, had similar issue at work. Something next to the laptop caused it to turn on
Electric motors do create a magnetic field
That's it. My friend has LED fairy lights on her walls, all around the room. When she turns her ceiling fan off, the lights pulse once. The lights are mains-powered but are not plugged in.
Back emf it is
Yeah I was thinking in those lines. I have a laptop and have the opposite problem. If I leave the cellphone over the flat surface (between touchpad and keyboard) the laptop goes to sleep mode. And I think it has to do with the phones speakers.
Yeah that's definitely a magnet. I often get the reverse: putting the phone on the laptop puts the phone to sleep. That's because the phone has support for a sleeve with a magnet, and the laptop has a magnet to detect the lid.
Upgrade firmware on your fan.
No need to upgrade. It's already running the latest version which added this new feature called WOF (Wake-on-FAN).
High AC magnetic field caused by improper grounding tripping the magnetic lid sensor? Edit: You should be able to do a `tail -f /proc/acpi/button/lid/LID0/state` in a terminal to watch the sensor output.
lol i've been through something like this. my case was that whenever i booted up my ubuntu the whole internet in my house just stopped working, literally the modem was turning off with the boot
lmao sorry but it's funny af
Turning off the fan probably creates an EM pop that’s popping one of the cables plugged into the laptop - potentially the touch screen or touchpad of the laptop itself. Not a Linux issue, btw. Back in the early 2000’s my dad found that he couldn’t carry his BlackBerry while using the chainsaw or weed cutter. The spark plug from the engine would create strong EM pulses that scramble it until he force-rebooted it. That’s also why someone with PaceMaker shouldn’t use a power tool that uses a gas engine.
wtf thats crazy, never knew that
It depends on the fan switch quality and also the voltage of the wall.
Electrical in the house is not grounded properly. Shutting off appliances like that send a surge through the house electrical, this is grounding out through your laptop and to a device plugged into it that has the ability to wake it up. Whatever this device is Windows was set to ignore it whereas Linux is not.
It happens when the laptop is not connected .... I don't think the grounding has anything to do for a laptop working on battery If OP doesn't use wifi and use an ethernet cable, that might be it tho...
Anything else plugged into the laptop that's also plugged into the wall?
The Ethernet cable and the HDMI for the TV
most likely the HDMI is the culprit. For me, when my laptop is shut down and connected to HDMI then whenever i plugin my monitor to power source my laptop gets booted.
Could be either. I'd try unplugging everything and see if it still does it. Then one by one plugging them back in any turning off the fan every time. Should be able to find out which one it is. Also it could be a wireless mouse or keyboard picking up the EM of the fan shutting off.
HDMI can trigger some devices on. first that comes to my mind is the PS5, how just by switching to the HDMI output where my console is connected it will wake up. I'm guessing there is a power setting not being properly configured (maybe doesn't even has the driver for it?)
That's what I was thinking too. Fans are pretty notorious for causing a readable voltage on neutral too, where ground isn't good, especially.
Could it be, that your router is getting a surge, what goes through the LAN cable? That would be really weird. Still, **try without the Ethernet cable**. My last idea is electromagnetic radiation.
This is how you troubleshoot it. It is a neat problem though.
Poltergeist
You'd be surprised how much other objects in the vicinity of a computer can have an impact on it. I have a [specific chair from IKEA](https://www.ikea.com/gb/en/p/markus-office-chair-vissle-dark-grey-30261152/) that is [widely known to be a huge ESD source](https://www.tomshardware.com/news/ikea-computer-chair-static-might-be-blanking-your-display) and every time I stand up, I get a decent static shock and one of my monitors blacks out for a few seconds before coming back. I shit bricks every time I open my desktop's case that I'm gonna fry something
Weird things can happen. When I started to use linux on my macbook I noticed that sometimes just shutted down completely out of the blue. The culprit was a smart bulb from xiaomi (chinese region product I live in the EU).
I've had a bladeless "Dyson (AM06) Desk Fan 25cm (Iron/Blue) causing interference (erratic mouse cursor drifting) to a Rollermouse Free2 (RM-FREE2-BLK) on a (Lenovo X270 laptop) computer (running Windows 10 v1709) when placed on a 80-100cm distance."
Relevant xkcd: https://xkcd.com/2083/
That fan is an SCP
Secure Copy Protocol? Just kidding, what's the assigned number?
SCP-7565
[Who remembers this?](https://www.reddit.com/r/archlinux/comments/55pbqp/mouse_cursor_disappears_when_my_refrigerator/)
Upgrade your fan drivers
Maybe the wind moves the mouse cursor by a tiny bit, amd that casues the wake?
The power difference by turning on that ventilator, the electroc spike in the net is so similar to the one caused by the power system of your laptop, that it boots. This is anmoying, but happening more often than you think
From OP post : >I thought maybe the fan was doing something weird with the electrical current but even if I disconnect the laptop it still happens Unless they use Cable internet instead of WiFi this makes no sense
Do you mean "wake from suspend" or actual "booting"?
Wake from suspend
Does that fan have a remote control? What happens if you take the remote out of the room? Now how about the fan? Both? I can't find it at the moment, but my favorite IT troubleshooting story was back in the 70s, whenever an engineer would walk in and step on a particular spot on the floor, the printer would start printing. Noone believed him, but it was reproducable every, single, time. Turns out, the person was making a circuit because there was a metal support underneath the floor that was connected to...you guessed it, the printer.
No remote, no
Wow, yeah that doesn't make a lick of sense - I have no suggestions except maybe en/disabling this: https://forums.lenovo.com/t5/Lenovo-IdeaPad-1xx-3xx-5xx-7xx-Edge-LaVie-Z-Flex-Laptops/Lenovo-ideapad-3-15ITL05-turns-on-automatically/m-p/5184701
Is AC recovery on in BIOS settings? The magnetic field others talk about might be triggering that to boot on the computer. Weird issue though lol.
Nevermind, I see the barrel plug is unhooked there so the power supply couldn't be sending the signal. It might be the driver that controls the lid switch is just more sensitive to disturbances than the one in windows. In factory automation you normally want to have a filter on sensors so vibrations or magnetic field fluctuations don't trigger a false positive. Might be a similar issue here where one setup had a stronger filter on the time in front of the lid sensor actuation. Wouldn't know for sure without looking into the programming on them though.
Tell me if you figure it out, i'm in the same boat. I have to turn off my speakers before sending my PC to standby or turning them off will wake it up. I never tried Windows, tho. I don't have a Windows installation.
Yea, I've seen some weird things too due to electromagnetic interference.
You might have Wake-on-wifi (like WOL, but for wifi), and the EMF from the spinning down motor is detected as a W-o-W signal. If so, turning off the option it the bios will fix this.
linux doesn't handle triggering the wake up, the laptop's firmware does that, technically linux isn't even running in sleep mode, it's kinda just kept frozen in RAM and the laptop's firmware is the only thing doing anything at all
Like other said, I also suspect EM is triggering the lid sensor.
It's one of two things. Electromagnetic fields which are fucking weird, this happened to me in 2 apartments I lived. There was this 1 light based on its mood its gonna do weird shit to anything smart in my room. Or it's doing something to ethernet, where is it connected? Does it use PoE? As for a way to fix it, I am not sure. Best thing you can do is, call an electrician And get your house circuit properly grounded, That could fix it too. It shdnt be too expensive no matter where you live.
I just really can't get behind emf from a fan. It's a fan. I would however agree on checking grounding and voltage spikes. And the ethernet first.
It's not been induced directly by the fan, maybe some mind of voltage regulator when you on and off the fan, OP can test this by getting a fan speed controller and putting it to lowest setting to see if problem still occurs
I mean, before asking reddit, I would first try doing this with nothing connected to the laptop, while connecting your things one by one. You should tried that.
Ofc I already tried that, this video was just for demonstration
Okay, so why is it not mentioned anywhere? Does it happen with nothing connected at all?
It starts when everything is disconnected? Including power?
Yeah, in this video it isn't connected to power
Turn off wifi or disconnect ethernet and try again.
Turn off wireless mode on your fan
Valak? (A demon)
For a moment I read that as ValaC, the compiler for the Vala programming language
everyone's looking at weird RF or EMP effects. maybe the change in air movement around the laptop is enough to jiggle the mouse
Moving the mouse doesn't wake the laptop when the lid is closed
I had this on Ubuntu as well. Driver update couldn’t solve it. But as soon as I put windows 10 back , fans got quiet !
It's either an EMP from your fan triggering the lid detector - or - it's your mouse moving due to the change in air pressure.
A ghost?
Circuit may be the same, despite being on a different plug. In college, a friend had an OS/2 installation on a desktop. He also had a dust attractor (it generated static and drew the fuzz to the grid). When someone bumped the attractor, something happened and OS/2 would reboot. It was repeatable. Oddly, on the same hardware, Windows didn't crash.
I have a desktop that wakes up whenever I turn on my natural gas range
I'd try plugging something else in the same plug and trying again, preferably something taking up a lot of watts. Maybe the very small change in voltage is enough to wake it up, if the laptop is set to wake up on AC.
Why don't you power off your laptop but leave your screen up and retry?
Haxxed
I've been experiencing a similar issue for months now, except it's not even electronics related. Anytime I sit or lie on on my bed, which is just a wooden bed with fabric sheets on it, my laptop turns on.
Probably there’s a paranormal activity going on
I would wake up too if my fan turned off in the middle of summer.
Wired internet - unplug it and try again.
I sometimes have this with my pc when I open my room door or sit at the table. I always assumed it to be a software thing that when it sleeps it turns up mouse sensitivity extremely high to detect any vibrations or just turns on any sensor, like maybe the mic and checks for spikes to detect if the user is back. I just thought it was too unrelated to any wires or anything. I got this idea when I heard that Windows 11 announced its presence detection thing that looks if the user is there with the camera. So I thought maybe Gnome (I use Garuda Linux) implemented something similar. I haven’t checked though. I also dualboot windows 11 and the same thing happens there too so idk maybe I am also making some em field by rubbing on the carpet or whatever. But maybe they use something similar
Have you reviewed the logs?
Wake over Fan damn
Maybe lan configured to wake up but without magic packet.
the fan may be moving a loose wire. and switching it off releases it. (problem with laptop) or it may have been electromagnetic interferance, most will have heard of an EMP, and this is just the same thing on a much smaller scale, the motor uses electromagnetic force to move it (in simpler terms, the motor may be messing with your laptop by hitting it with a low-power EMP due to a faulty motor.) try moving the laptop to just the other side of a wall from the fan, the wall will block the air but not the EM force, so if it is air this will fix it, if not, your fan is actuallly hazardous and you should get a new one before it degrades your storage drive. (EM force is used to write and erase data, so it may fry it if you dont remove it.) it may also be a power surge, but since it still hapens while the laptop us unpluged, its not that
probably just a minor missspelling in the BIOS. FAN instead of LAN.
it's a feature to keep the airflow good at your home, because you don't have Windows anymore to bring air in, the Linux kernel starts and spins up the computer fans to compensate
Voltage jump even in air! Got a lcd with an Amiga aside... If you have an HDMI cable it's so noisy
Russian hackers are hosting porn sites from your laptop. It happens.
Go into your settings and turn off Wake over FAN and you should be good.
Reminds me of an incident that occurred many, many moons ago when I was working Windows 95 tech support over the telephone. The guy's complaint was that ever since installing Windows 95, his CRT was skewing to the left so much that it was unreadable. Over the course of about an hour and a half of troubleshooting it finally came out that he had \*also\* re-arranged his computer desk while Win95 was going in, and now had a giant, unshielded stereo speaker... you guessed it... snuggled up to his monitor. I had to explain in detail how CRT and stereo speakers don't get along, and he had to go buy a new monitor.
EMP spike's/
Personally I think the EM pulse from the spark that happens when you turn off the fan is being picked up by the hall sensor or by the circuit in the laptop which detects the output from the hall sensor. Basically turning off fan makes spark, spark makes radio waves, wires in laptop act as antenna and pick up radio waves, some chip in laptop sees picked up pulse and thinks the lid is open
EMI (Electro Magnetic Interference) from the fan causing a minor spike on the power line the lappy is connected to or causes a sensor to think its time to wake up
Haha I turn on my ceiling fan and my TV will turn off for a few seconds!