Wobbly type cover trackpad

[icelava]

For quite a number of months this year, something strange has happened to my SP4's type cover. When I'm carrying it around mobile, the trackpad works steadily. But when I return to my desk, where I have a bluetooth Sculpt Comfort mouse to use, the trackpad sensor goes rather haywire and sends the mouse pointer wobbling all over the screen; can't get any precision movement.

I've been operating this computer since 2016 and never encountered this problem before - both trackpad and mouse used to work (properly) side by side. I'm clueless what type of interference the trackpad is getting when on my desk.

Anybody experienced something similar before?

 

[icelava]

Strange as it may seem, I suspect, this has something to do with my standing fan in the room. When it's switched on and blowing air in my direction at the desk, there seems to be disruption to the sensitivity of the trackpad - wobbly, jumpy mouse pointer; or sometimes can't detect my finger and no movement. Once I switch off the fan, the sensitivity seems to restore some time after the wind is gone.

I have to try more experiments to point out it if it's indeed the ventilation air flow that messes with the trackpad. If anybody has any scientific understanding on physics mechanics of trackpads (particularly the one with the type cover), please educate me on the matter. Thanks.

 

[sharpuser]

This problem is more common than you may think.

One of two things is going on here:

1. The fan may be altering the distribution of humidity in the room, especially if a window, bathroom, fountain, water feature, fizzy soda, of other object which may have elevated moisture content is nearby. Trackpads sense a change in the dielectric property of air, which is sensitive to humidity. This is also why sometimes a very dry finger, or a finger covered by a layer of glue residue, etc.) may not be detected properly by a trackpad.

2. (less likely) The fan (electric motor) may have dirty or improperly grounded electronics, thereby disturbing the dielectric property of the air.

I hope this helps.

 

[icelava]

Well I live in Singapore, region with high humidity. The fan is merely blowing air in my room/home, which I shallowly assumed wouldn't be a so much of a difference simply by circulation. I'm not sure how I can conveniently test the property of air when it's still versus rapid movement.