Bizzare Glitch - Any Ideas Why?

[Yosemine]

Hello, I don't have any clue what could cause this so if you know it would be appreciated.

I'm creating an app that uses multitouch to draw shapes to practice programming. Everything works fine EXCEPT when I place the Nexus 7 either flat on my bed or flat on the carpet. If I put it on my bed or carpet, my app slows down severely and acts as though I pressed the screen quickly in succession. I tried this many times and it is definitely tied to its location!

Really confused, does anybody have any idea what this could be a result of? 

[Yosemine]

Hmm I took a video of it here using a multitouch app:



I was surprised to see that on YouTube, others have reported this same issue. Could you please check to see if this is a defect, or "just the way it works" for me?

[Babyfacemagee]

What if you lay it down and do the same thing on a hard surface like a table?  Does it do the same thing?   Could have to do with the amount of pressure you're putting on the screen.  Since the surface is soft...you're pushing the tablet down a bit into the bedding or carpet and your fingers aren't making as solid contact with the screen at the points further away from your body as the points close to it.  It's basically kind of an illusion you're doing on yourself.  Notice in that video the Nexus 7 is actually hanging partially off the top of the bed.   So it's not really straight and on an even surface.  If you saw it from the side you'd probably see that the top of the tablet was angled down and slightly further away from the user...hence the contact with his fingers was less.   The display therefore feels the closer finger pushing harder than the further finger...causing the anomaly. 

[Yosemine]

That's a good thought, and one I had as well, but I tested carefully when not on camera and I know this isn't the problem. Also, if plugged in to a computer, the issue goes away. I took a video of my application in use to show the problem.

Please ignore the mess. 

[tsruggles]

Perhaps the rotation sensors are playing a part in the issue as well? If the device is constantly trying to figure out what orientation it is in, it could mess with the app. Seems like laying flat would be likely to trigger the sensors with very minute movements. Just a thought.

[Yosemine]

Yep, thought that might play a part too, but I have (off camera) tested it by putting it at a slant against my bed frame. Same issue if it isn't being held.

I should clarify I was wrong about it only glitching on my bed and carpet. The reason for this was that if the device is plugged in, it won't show the problem, and previously every time it was on the table it was plugged in.

EDIT: Could people reading this try to open up your browser and attempt to pinch zoom into the page while leaving it on a surface unplugged? When you pinch zoom, do it so your fingers are directly over one and other with the screen in portrait, so that a line drawn between your fingers is parallel with the long side of the screen.

This causes glitches for me as well.