LCD Touch Buttons

What is the technology behind the LCD touch buttons?

I noticed that sometimes they are activated with false positive, assume high temperate changes becuase i open the fridge and it activate. Just curious what is driving them?

Bangle.js: Opening and re-assembling

In this video i notice 4 connections coming out of the display, does that mean it has 4 touch locations?

What is the advantage to having only 2 touch spots on the display, compared to entire screen being touch? Less software operation ? Or when they only want to detect swipe action?

Is the 2 touch feature a hardware limitation or a software/design limitation?

https://youtu.be/tPx2d493GoI?t=90

Found this at 1:30 you see something which might be very similar?

Capacitive Sensing, think its this
https://www.youtube.com/watch?v=bhspPkxOMxs

As far as I can tell the display is 4 areas, but because of the limits of the touch chip they use, they are connected together into just 2 areas. I think the limit is probably because of a lack of IO on the microcontroller.

I think the actual controller is the Holtek BS83A02A - link to datasheet on https://www.espruino.com/Bangle.js+Technical#hardware

Honestly, I'm not sure about what could be causing the accidental triggering - but as far as I can tell the touch controller automatically calibrates, so if the capacitance around it changes suddenly it might trigger.

Hey there, unfortunately I am observing constant accidential triggering of touch buttons on my Bangle.js (since the beginning).

When I open the timer app it will mostly trigger first on right side (the Seconds increment to 1, and after that also on the left side). Sometimes there's a little time between, sometimes it is as fast like swiping left. This is makes music control and the touch driven apps rather unusable for me.

Is there any reason we could think of to fix that - maybe as simple as a disassembly and cleaning out, or add a small sheet to separate/isolate two components inside that interfere?

Argh, sorry to hear that - it could potentially as simple as cleaning it out. There's some oil used during assembly of the buttons and I've seen it dribble out a little. I guess if that is on the touch panel it could cause some issues.

Are you wearing or holding the rear of the watch at the time? I've found the touch control is much more reliable when you're wearing the watch for some reason.

I tested this while wearing it, lying it on table, holding it in different ways, with or w/o touching the side buttons, etc... it's always like the described behaviour.
Tried also rebooting while in these 'modes'.

But OK, so I'll give it a try and open / clean it.

You could always send it back for a replacement. What I'd normally do is say to take the straps off and send just the watch body back in a jiffy bag, then I could send a replacement one out. If you're interested let me know the address to use via PM and I'll send you the return address.

It's a shame because we do test the touch sensors here before sending them out, so maybe something moved around in transit.

Good news from here at least; there was indeed much grease inside the screen an on the inner cover next to it. After cleaning both thoroughly, the ghost touches are gone, and everything works as expected.. yay!

That's great news! Thanks for letting us know, and for fixing it yourself!