This is topic Laptop touchpad wackiness in forum Film-Yak at Film-Tech Forum ARCHIVE.


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Posted by Leo Enticknap (Member # 534) on 09-17-2018, 05:59 PM:
 
I'm currently on a trip doing an install in Petoskey, MI. In my hotel room, my laptop touchpad is utterly unusable. As soon a I put my finger on it, the pointer wobbles around the screen like it's been smoking crack. When the laptop is in the booth of the theater where I'm working, three miles away, it's totally OK - as if nothing had ever been wrong with the touchpad.

I'm guessing that there must be a source of EMI in or close to my hotel room, but I'm buggered if I can find it. I've tried moving from the desk to the couch to the bed with it - no difference. I've unplugged literally everything in the room that plugs into an outlet: again, the mouse pointer still vibrates. No difference if I pull the power supply and run the laptop on its battery. But as soon as I'm out of the hotel, it's as if the problem never existed.

Of course, after the first evening, I ordered a replacement touchpad on Amazon, which it now looks like I'm not going to need. Working now with a wired mouse from the Walmart across the street without any problems. But I am very curious as to what could be causing this. I can't see any obvious source of trouble near the building (e.g. a cell tower), either.

Anyone else encountered this?
 

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Posted by Rick Raskin (Member # 1561) on 09-17-2018, 06:06 PM:
 
I've had laptops behave strangely in hotel rooms too. I don't think its poltergeists but maybe related to proximity detectors that some hotels have. Or, as one of my college professors used to say, IPIO (the Inherent Perversity of Inanimate Objects).
 

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Posted by Carsten Kurz (Member # 5396) on 09-17-2018, 06:13 PM:
 
Maybe talk to reception. Chances are they heard about it before.

- Carsten
 

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Posted by Leo Enticknap (Member # 534) on 09-17-2018, 07:22 PM:
 
I just did, and it's a new one on her. She's had consistent complaints of poor Sprint cell reception ever since the hotel opened three years ago, but none about laptop touchpads acting up.

If it is a poltergeist, (s)he has a unique sense of humor; that's for sure.
 

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Posted by Harold Hallikainen (Member # 5405) on 09-17-2018, 09:37 PM:
 
The poor cellphone reception is an interesting issue. Perhaps the weak signal is causing your cellphone to run higher power and getting into the laptop.

I had an issue in a theater where there was a cell tower across the street from the theater. RF was getting into the HI output of the sound processor. On high level audio, the mute button would flash and then eventually mute. I had to go to the site near Las Vegas NV to figure that one out.

Harold
 

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Posted by Leo Enticknap (Member # 534) on 09-18-2018, 06:22 PM:
 
I think you cracked it! I just tried shutting my cellphone completely down, and while that didn't totally stop the wobbling pointer when the touchpad is operated, it did calm it down to only just shaking a tiny bit. Booted the phone back up, and it was snorting crack again.

Presumably, the small residual wobble is from phones in the rooms around me (the walls in this place are paper thin, as I discovered at around 2am on my first night here, when I was woken by a lady in the room next door threatening to beat her mother-in-law "to a bloody pulp" at the top of her lungs).

Thanks!
 

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Posted by Marcel Birgelen (Member # 6801) on 09-20-2018, 02:14 AM:
 
I've never experienced cellphones to be interfering with touchpads, although you sometimes hear them interfering with badly isolated low-voltage sound circuits. Actually, you would expect modern touchpads to be designed to cope with expected RF interference, everything else could be considered a design flaw.

It's also interesting that it stopped the moment you turned off your phone. Because, in order to save energy and bandwidth in the ether, mobile phones usually only communicate with the cell-towers around you if there is something to communicate.

Obviously, modern smart-phone gizmos with a lot of internet connected stuff running on them tend to be quite chatty, but unless they're constantly downloading huge chunks of data, there should be significant periods of radio-pause.

It would be interesting to see an RF spectrum analysis of that particular room.

RF interference can have some strange sources. I once lived in an apartment where the crappy, leaky microwave oven of one of my neighbors caused the WiFi in the entire building to collapse. We eventually bought her a new microwave oven to get rid of the problem.
 

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Posted by Randy Stankey (Member # 64) on 09-20-2018, 08:08 PM:
 

quote: Marcel Birgelen

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RF interference can have some strange sources.

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In a house I used to live in, internet was only available by dial-up. (This was in 1999.) The connection wasn't bad but, when somebody flushed the toilet, the modem connection would go down.

After lots of head scratching, I finally figured out the cause.

The house's water supply was from a well. When a toilet was flushed, the water pump would turn on. The electric wires for the water pump were about a foot away from the incoming phone line, and running parallel. The interference from the pump was drowning out the modem's signal.

I ended up re-wiring the phone lines, making sure they were well separated and running at 90 degrees from any electric wiring wherever possible. Problem solved.

But it's still weird to think that flushing a toilet could cause your computer to malfunction!
 

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Posted by Monte L Fullmer (Member # 2797) on 09-21-2018, 04:23 PM:
 
I use a wireless mouse with my laptop. I can get more accurate. Yet, depends on the laptop if the mouse and touchpad wants to argue.
 

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Posted by Dave Bird (Member # 490) on 09-22-2018, 02:07 PM:
 
>>>But it's still weird to think that flushing a toilet could cause your computer to malfunction!<<<

From the days of limited bandwidth and lots of users in the house, I still accuse my kids of "clogging up the internet".
 

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Posted by Leo Enticknap (Member # 534) on 09-22-2018, 02:10 PM:
 
I don't like the hassle of having to carry a mouse around with me, and, thankfully, am comfortable with a touchpad (as long as all the annoying "features," such as it thinking that you're right-clicking if you press too hard on the pad area, are disabled).

quote: Marcel Birgelen

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It's also interesting that it stopped the moment you turned off your phone. Because, in order to save energy and bandwidth in the ether, mobile phones usually only communicate with the cell-towers around you if there is something to communicate.

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quote: Marcel Birgelen

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It would be interesting to see an RF spectrum analysis of that particular room.

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