Samsung Galaxy S9 Accidental Touch Protection Not Working?

I recently had an experience with my Samsung Galaxy S9 phone, which was recently upgraded to Android 10, and which, in more recent days, received another update to its current Android 10 version. The experience was that, after a day at a sunny beach, while it was very hot, I came home and inspected my phone, and seemed to find that somebody had been having a party on its touch-screen. Normally, I’d say that not very much can go wrong, unless the accidental activation of the touch-screen also managed to enter the password that protects the phone. But, contrarily to that first approximation, even with the lock-screen locked, there are quite a few layers of widgets that a party-goer could go through, and leave the UI in a confused state.

And so, I started to ask myself what might be causing this. Was it me, perspiring under my shirt? Was it the excessive heat, somehow affecting that one chip in the phone that also controls the touch-screen? The conclusion that I came to, was:

  • Excessively bright sunlight, seeping through my lightly coloured shirt’s pocket.

I typically have a feature enabled, that’s called “Accidental Touch Protection”, and this screen-shot shows where it can be found on the S9 (Hint, this screen is reached through ‘Settings -> Display’…)

Screenshot_20200813-140351_Settings_e

The way this feature works, also explains why sometimes, it may not work. Most modern smart-phones have a photo-diode that acts as a light-level sensor. When the light-level is below some threshold, with this feature enabled, the screen is turned off. This low light-level indicates to the phone, that it’s either inside a pocket or a bag, and that capacitive contact with the screen should be ignored. The problem?

  • If the light-level is above this threshold, the phone has no AI to tell it, that the same light-level is due to extremely bright light to begin with, not being filtered below a sufficiently low level, just due to the cloth in a pocket. And thus, such a level is taken to mean, ‘The phone is in the open, and waiting to be used.’
  • With the upgrade to Android 10, for some reason, the threshold required was set to an even-darker threshold, than Android 9 had it set to.

Possible solutions?

  • Put the phone in an additional enclosure that blocks light, Or
  • Disable the Always-On Display during Summer months, Or
  • Wear a darker shirt? Or
  • Stay out of extremely bright sunlight…

I can’t think of much else that helps, on the assumption that indoors, the feature works as it should.

 

Dirk

 

Overheated Circuitry

One of the things which I do frequently, is ‘walk around’, or, ‘use public transit’, with my disposable earphones plugged in to my Samsung Galaxy S9 Smart-Phone, and listening to music. These earphones are clearly not the ones, which had the AKG seal of approval, and which shipped with the phone. But this week-end marks the second heat-wave this Summer, when outside daytime temperatures exceeded 31⁰C, with direct sunlight and not a cloud in the sky. And under those conditions, the battery of my phone starts to hit a temperature of 42⁰. One of the facts which I know is, that Lithium-Ion batteries like the one in my phone do not tolerate temperatures exceeding 41⁰C.

A peculiar behaviour which has set in for the second time, during this second heat-wave of the season, is that the music I was listening to would either back-space to the beginning of the song, or skip ahead one song, or just stop. So, a catastrophic sort of explanation I could think of would be, that the entire phone, with its battery, is finally just having a meltdown. But, a second possibility exists, that merely the chip in the earphone-cord could be malfunctioning. After all, the little pod in the earphone-cord has one button and a mike, and it’s actually cheaper to mass-produce the chip that makes it work, than it would be to mass-produce other sorts of discrete components. One cheap chip could just be malfunctioning in the extreme heat, and not the entire, complex circuitry of the phone. (:1)

The earphones cost me about $15, while the phone is much more expensive than that.

But even if it was true, that only the little remote-control in the earphone-cord was malfunctioning, this can lead to impractical situations, because just random patterns, of unreal button-press-combinations, could also send the software of my phone into a confused state, and even so, if the circuitry in the smart-phone never malfunctioned. This behaviour could get misinterpreted by the security apps of the phone, let’s say, as though somebody had ripped the earphone-cord off my head, and thrown all my possessions around.

All that was really happening was that my music was no longer playing, as I was walking home normally, in the heat, with my overheated electronics. And when I got home, my actual phone never displayed any signs of having malfunctioned.

(Updated 8/17/2019, 17h50 … )

Continue reading Overheated Circuitry