Talk:Touch screen

As a note, what I mean by unlimited points for capacitive sensors is that AFAIK the sensor is a grid of capacitor plates, and it can scan every single one and analyse it, same as how a Realforce keyboard does NKRO (which is why the Realforce doesn't need diodes). This has always been true, but computers didn't have anything useful to do with the multiple points. It was only with the iPhone where Apple decided to create a sensor that would actually return multitouch data, and a GUI that would process this data. Think how an internal PS/2 Synaptics trackpad has a pressure/mood indicator on the system tray: it knows how much of the trackpad is covered by your finger, but a PS/2 pointer device can only send x/y co-ordinates. Multitouch was possible at the hardware level from the start, I think, even if there was nothing that the computer would be able to do with that information. (I would imagine that a capacitive sensor doesn't even require touch, since capacitor plates have a dielectric between them by definition, but that it's programmed to behave as though it does, based on particular readings, be it area covered or capacitance strength, otherwise it would be unusable.)

Compare this with a resistive sensor that can only sense one pressure point. If you pressed multiple points you'd probably get crazy readings. The stupid things don't even sense a single point correctly – all my Psion PDAs jitter, and after POS last screwed with my Revo, you can't even pause when dragging with the scroll bar as it bounces up and down like a crazy thing from the massive jitter. Similarly, dragging a window causes it to shake like it's dying of hypothermia. No idea WTF they did to it, only that they exacerbated an existing limitation/flaw with the resistive panels.

Daniel Beardsmore (talk) 05:37, 14 October 2012 (CEST)