OT touch screens

I've got a tablet. (nexus 7) I assume its touch screen sensor is capacitive. Holding the tablet in one hand and poking at the screen with the other, works fine. But sometimes when on a desk, and all the time at night in bed. The sensor won't respond to one finger and I have to add a hand or use two fingers. With two fingers, the 'non-moving' finger has to be on the non-active part of the pad. Else having two fingers waving around causes all sorts of unwanted inputs. (I need to turn the page with a swipe.)

So I'm thinking I just need to make electrical contact. I don't really want to plug something into the usb port 'cause that is the weak link on these things. (I've replaced 2 so far.. (my kids devices)) And I was thinking of a hand sized piece of copper tape on the back of the tablet and then a wire, to electrostatic wrist band. (I'll remove the 1 meg resistor)

I'm looking for other ideas.

George H.

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George Herold
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I have the same tablet (2013 2nd generation version): Corning Fit Glass 10 point capacitive touch screen.

Mine previously had the same problem, where it would not respond reliably to one finger or one handed operation, but after an Android update about 2 years ago, the problem went away. I just tried it on my non-conductive bed and table. It works with one hand or one finger. I have no idea what might be happening with yours. Low humidity perhaps?

Try one of the numerous digitizer test programs:

Maybe try a stylus?

Perhaps grounding through the USB port might help. As you mention, a micro-USB plug is going to be quickly broken by the kids. You might consider a right angle micro-USB plug, which presents less of a lever arm.

As for replacing the micro-USB Type B receptacle, I've replaced about

10 of these on various tablets and cell phones for friends and customers. The receptacles are commonly available on eBay or Amazon. They can be replaced with a hot air SMT desoldering machine or very careful micro-soldering: etc...

I don't know about using a Dremel cutoff tool to remove the connector: Rose Metal is a bismuth based alloy low melting point solder.

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Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
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Jeff Liebermann

Try this app: I just downloaded ran it. It claims to have reduced my response time by 7 msec, which I shouldn't notice. However, after a restart, it seems to be a bit more reliable while playing Solitaire. No clue how it works or what it does. When I tried to run it twice, it claimed that the touchscreen doesn't need recalibration and that it would inform me if anything has changed that might require calibration.

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Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
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Jeff Liebermann

Thanks Jeff, I'll try some of the apps. (I'm not very hip when it comes to apps... I'll get the 'boy' to help me.) I bought a used nexus so maybe it doesn't have the latest update... I'll have to check that out too. Re: micro sub replacement, the first time I did that I used my solder sucker and ripped up some of the pads... blue (wire wrap) wire to the rescue. I really need someone to show me how to use solder wick properly.

Semi-related, when I was at a trade show I walked by this new Sony tablet. Digital paper.

formatting link

I was busy at the trade show and didn't have time to play with it, but it looked cool.

George H.

Reply to
George Herold

Settings -> About tablet Android Version = 6.0.1 Android security patch level = August 5, 2016 Build number = MOB30X

There are two version of the Nexus 7. 2012 and 2013. It's easy to recognize the difference. The 2013 has a 1920x1200 display while the

2012 version has a 1280x800 display.

There are probably numerous videos available on YouTube to show you how it's done. The only thing I can add is that when using solder wick to clear a hole, use a diagonal cutter to put a point on the end of the braid and shove that into the hole. The reason you ripped up the traces is you held the iron on the pads too long. Small tip, tin the connection, maybe some flux, very hot tip, and work fast is the way to do it right. The idea is to keep the heat affected zone small. A low temp tip will require that you hold the iron on the connection for tool long, resulting in pads and traces floating away.

Personally, I prefer a motorized solder sucker or the manual piston equivalent. I used solder wick only when cleaning out holes or for inaccessible parts where the desoldering tip won't fit:

I have several Kindle paper-white display tablets. Displaying a color image on a b&w screen is sometimes a problem. Shades of gray is so

1950's. I use the tablets for displaying PDF's and documents at meeting. One nice feature is some of mine have a cellular data radio built in. If I want to send a document to the device, I just send it to an email address and it appears on the directory list. For format conversions, I use Calibre: on a PC.

I have no idea if the Sony tablet is an improvement on the Kindle. I can't read my own handwriting and I doubt that scribbling on an $800 electronic Etch-a-Sketch will improve the situation.

Mostly, my Chromebooks (Acer Chromebook 14 cb3-431) have replaced the various Kindles for meetings and document handling. They're also much cheaper: and will do more things, such as drive overhead projector using HDMI, use a mouse, attached keyboard, and some IO ports.

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Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
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Jeff Liebermann

Yup, that's what mine displays too.

Oh boy, you expect me to count all those pixels. :^)

Right, it was my manual pump that yanked up a trace/pad. I'm mostly just a hack when it comes to soldering, I don't do repairs enough to become good at it.

Thanks again, George H.

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George Herold

There's an app for that (and probably for everything): Or, you can just use a magnifier with a measurement ruler reticle and scale the count for the screen size.

Learn by Destroying(tm). Ok, you're forgiven. Delsoldering tiny parts is not easy. If you don't care about the condition of the old connector, just clip off the leads, remove the remains of the connector, and then individually unsolder the leads.

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Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
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Jeff Liebermann

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