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’…)


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.




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