NST: erratic or unresponsive touch-screen (and it's not caused by dirt)

marcoNST · May 13, 2014

Hello there,

I decided to post in here after doing extensive research online but having found no answer to my problem....

I have had a rooted (with NookManager) Nook Simple Touch that worked perfectly until I went travelling across tropical countries. Since then, I have seen a progressive degradation of the touchscreen, specifically I noted the following:

Buttons/icons in the lower half of the screen, when tapped, do no respond. Instead, buttons/icons directly above them (on the upper part of the screen) do respond to the action.
When the keyboard is active and letters are tapped, you get one of these random behaviours:

the letter appears on the screen, but 2 or 3 of them, even if the letter is tapped once.
the letter above the one tapped, appears on screen: e.g. I press "q" and "a" appears on screen; I press "backspace" and the letter "p" appears on screen.

Following the recommendations of many forums, I cleaned thoroughly my screen, however this does not seem to resolve the problem. I also performed a factory reset and re-root, still the problem persists (though, after a new factory reset, the erratic behaviour is less frequent, at start, but then It worsens as time goes by).

The only thing that changed is the fact that I am now travelling in hotter countries and maybe the Nook is sensitive to temperatures constantly above 30C. so I suspect it may be the cause.

Has anyone experienced similar problems?

Thanks

Marco

Renate · May 13, 2014

The processing for the zForce touch screen is done by a TI MSP430 processor.
This is separate from the main OMAP 3621 processor.
They communicate over I2C.
There are no user-friendly diagnostics built in.
It's difficult to identify problems.

I have a unit with a similar problem.
I've been starting to look into this.
I'd like to make a user app that deals with the more common problem of dirt and would actually indicate where the dirt is.
(The problem with this unit is not dirt either.)

Renate · May 14, 2014

I've got a new utility for debugging problems with the touch screen.
At the very least it should be able to tell you where the dirt is when it is dirt.
I need to do some polishing up on it.

The screenshot is a touchscreen with one touch in the middle.
The lines at the top and bottom are marginal performance of the edge sensors.
When there is no touch all the lines should be light gray.
The black indicates where it thinks there is an obstruction.

marcoNST · May 14, 2014

Thanks so much for your response, Renate.
I very much look forward to your tool!

It is quite a frustrating behaviour that seriously limits the interaction with my NST (last time it took me 1 hour just to be able to type a wireless password correctly!).

Marco

Renate · May 14, 2014

Here's an alpha version of the utility.
When you run it, most of the lines should be a light gray.
Touch some place and it will show black lines.
Paste a screenshot if you would please.

I may be hot on the track of what the actual problem is.
Questions:

Did this happen slowly over time?
Was it humid there or just hot?

marcoNST · May 15, 2014

Renate NST said:
Questions:

Did this happen slowly over time?

Was it humid there or just hot?

Renate,

I'll try your utility later on today, after rooting again my net, and then let you know.
In the meanwhile, to answer your questions:

- yes, the problem started occasionally and worsened over time. Now, after 3 months from when I first appeared, I can hardly use the touchscreen
- it is hot and humid.

Renate · May 15, 2014

New alpha version.

Light line - open pathway working correctly
Dark line - blocked pathway
Dashed line - maxed out LED drive, something not optimal

Renate · May 15, 2014

Sorry, the latest version:

Overview, an untouched screen should have all light gray lines of some kind,
a touched screen should have thick black lines near the point.

Thin light gray line - normal, open pathway
Thick dashed light gray line - maxed LED drive, open pathway
Thick black line - normal, blocked pathway
Thick dashed black line - maxed LED drive, blocked pathway
Thick long dashed black line - maxed LED drive, zero signal

This would all be easier if I could just use colors!
Well, I could, but you'd need to take a screenshot to see them.

Update: Download Touch.apk in the signature.

marcoNST · May 15, 2014

Renate NST said:
Thin light gray line - normal, open pathway

Thick dashed light gray line - maxed LED drive, open pathway

Thick black line - normal, blocked pathway

Thick dashed black line - maxed LED drive, blocked pathway

Thick long dashed black line - maxed LED drive, zero signal

HI Renate!

I just ran your latest version and yes, I do have a couple of "<"-shaped thick dashed black lines in the middle of the screen and one thick gray dashed line at the very top of the screen. All the rest is thin light gray.

I'm gonna take a screenshot of it as soon as I get around installing QtADB (and the SDK) on my netbook I am currently using while travelling.

I just noticed that if I rub quite hard my unresponsive keyboard (for 10/15 seconds), the letters start to work properly again, until I keep the keyboard open. When I close and re-open it, I need to rub the keyboard again for a few seconds to get it to work again.
This also applies to any other area of the screen (buttons/icons) that does not work properly.
Needless to say, this behaviour is quite random.

Any idea about the cause and the remedy?

Marco

marcoNST · May 17, 2014

Snapshot of my nook attached.

Renate · May 17, 2014

Hmm, that doesn't look too bad.
Do this in an ADB shell:

Code:

cd /sys/devices/platform/i2c_omap.2/i2c-adapter/i2c-2/2-0050
cat ledlevel
echo 1 > forcecal
cat ledlevel

You can do this with the Touch app running.
Touch (and release) afterwards to see if the V in the center disappears.
Post the ledlevel responses.

marcoNST · May 17, 2014

Renate NST said:
Post the ledlevel responses.

First ledlevel (before "forcecal"):

Code:

09 09 104 111 06 08 095 105 05 05 100 106 03 03 102 087 03 05 088 089 06 03 098 082 03 05 090 075 03 03 093 084 05 06 095 088 08 09 090 092 09 09 097 098 

15 03 054 103 02 01 100 106 01 01 117 115 02 02 112 099 02 01 095 102 01 01 099 105 01 01 108 107 01 02 101 104 15 15 009 010 01 01 087 096 02 03 108 094 02 03 097 095 01 02 118 102 03 03 087 084 11 12 065 086

Second ledlevel:

Code:

08 08 071 078 05 06 079 076 03 03 078 076 02 03 075 082 03 05 080 087 05 03 080 075 03 03 092 073 02 03 082 081 03 05 078 067 06 09 080 090 09 08 095 088 

15 02 050 075 02 01 087 079 01 01 086 082 01 01 101 087 02 01 078 100 01 01 097 077 01 01 079 080 01 02 094 089 15 15 008 009 01 01 083 090 02 03 087 079 02 02 078 077 01 02 086 082 02 03 076 077 12 12 094 082

I didnt notice any changes in the touch screen after the ADB commands, even after a few touches. I restarted the Nook and ran the touch utility again, still no changes. The same pattern is still there.

Marco

Renate · May 17, 2014

I've been playing with my problem Nook and I've gotten it a lot closer to working.
The mechanical alignment of the components is very critical.
It's all held together with double stick tape.
Especially the top end is sensitive, that has the biggest span of plastic in the IR (internal) bezel.

But I don't think that this is your problem.

marcoNST said:

Your problem is clearly related to the left side (LED side) at the vertex of the V.
The two LEDs on the left, above and below are getting a fine response out of the two photodiodes on the right used by the problem V.
Put on your reading glasses and look very closely at the left edge of the V for anything odd.
There could be dirt internally between the internal edge of the bezel and the LED.
The LED itself could be semi-fried.
The LED driver could be semi-fried.

Depending on how sensitive a camera (and how lousy an IR cut filter it has) you have, you might be able to see the problem that way.
In a darkened room, point the camera as low as possible towards the left edge.
With your finger on some part of the screen you might be able to see a dull red flickering.
My cell phone can see that if pointed directly at the LEDs on the disassembled unit.

There is also the trick of using a photodiode on a mic input to a PC.

Oh, a new version of Touch.apk
It doesn't show anything different, it just updates periodically without a touch.
That's helpful if you want to try pushing on the case to see if things change.

Update: Download Touch.apk in the signature.

marcoNST · May 17, 2014

Renate NST said:
Your problem is clearly related to the left side (LED side) at the vertex of the V.

There is also one dashed grey line at the top of the screen.
Could it be part of the same problem?
Should I look for dirt in that area too?

OK, I inspected the area (without camera).
The edges of the screen are made by 2 layers: the hard plastic black casing that touches the screen and the rubber-y dark grey wrap material glued above it. Well, because of the heat (most likely!), the glue has lost its grip in some parts (so much so that i can slide a needle in these parts), including the LED area and dirt has crept in. I removed some of the dirt with the needle.

The hard black casing is still well attached to the screen.

I still have the same LED pattern. Is there a safe way to open the Nook and remove the dirt?
At least i can exclude one cause.

M.

M

Renate · May 17, 2014

The very top and bottom horizontal lines have a couple of bad design problems working against them.
I wouldn't be surprised if all Nooks had problems there.

The optical problem with dirt would be dirt on the face of the dark green inner bezel.
If you have dirt under the bezel that would relate to a physical problem affecting the optical alignment.
Use the new version of Touch.apk and see if you can squeeze the case at the bad spot and make the V disappear.
Try also bending (lightly) the edge backwards and forwards.
Do this and also try doing a echo 1 > forcecal at the same time.

If you have to take the bezel apart to try to fix this you'll be opening up a whole new can of worms.
That's what I'm trying to solve with my 2nd Nook.

marcoNST · May 19, 2014

Hi Renate,

I tried your solution (repeat the forcecal), but no joy.
At this stage, I am going to get a new one (or second hand) very soon as I really need a functional reader for my travels and Nook suits me well.
But I wanted to thank you for your help and good luck recovering yours!

Marco

P.S. Also I need to thank you for your Library app, I have been using it since rooted and loved it!

Renate · Jan 29, 2015

This deserves a bump.
I had almost forgotten about this utility.
My screen was behaving flakey.
Using the Touch apk I could instantly see where the problem was, know where to clean, and confirm that the cleaning worked.
Some of you out there with aging Nooks could probably use this.
Download in the signature.

Nitewolf588 · Feb 2, 2015

Not Working

I am in a similar boat with this. I apologize, but I wasn't sure if i would even be able to access the apk. The only sensors I know that definitely don't work are the ones that allow me to unlock my screen.

I've taken apart my Nook to look at the hardware and everything seemed fine, except for the fact that the tape around the screen was dirty. I wiped it down with a wet paper-towel, yet it still doesn't work properly.

Renate · Feb 2, 2015

It's not clear what your current situation is.
Your Nook is locked and you can't unlock it?
Do you have ADB running? You could delete the lock. (search this forum, it's there.)
Can you run Touch.apk?
Post a screenshot if you can.

NOOK!E · Feb 3, 2015

@Nitewolf588 @Renate NST Here's the mod to turn off slide-to-unlock.

NST: erratic or unresponsive touch-screen (and it's not caused by dirt)

Member

Recognized Contributor / Inactive Recognized Dev

Recognized Contributor / Inactive Recognized Dev

Member

Recognized Contributor / Inactive Recognized Dev

Member

Recognized Contributor / Inactive Recognized Dev

Recognized Contributor / Inactive Recognized Dev

Member

Member

Attachments

Recognized Contributor / Inactive Recognized Dev

Member

Recognized Contributor / Inactive Recognized Dev

Member

Recognized Contributor / Inactive Recognized Dev

Member

Recognized Contributor / Inactive Recognized Dev

New member

Recognized Contributor / Inactive Recognized Dev

NOOK!E

Guest

Similar threads

Top Liked Posts