Electronics notes/Touch screen notes: Difference between revisions
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While in general it's much easier for a driver to pretend to be a mouse, | While in general it's much easier for a driver to pretend to be a mouse, | ||
there are some DIY cases where | there are some DIY cases where you might want to consume its communication more directly. | ||
There does not seem to be a universal standard protocol for these serial resistive touch screen - but at the same time not a lot of distinct ones either{{verify}}. | |||
Even 'Elo' comes in variants: | |||
* E271-2210 10-byte protocol | |||
* E281A-4002 6-byte protocol (legacy) | |||
* E271-140 4-byte protocol (legacy) | |||
* E261-280 3-byte protocol (legacy) | |||
...but e.g. the linux driver code suggests it's not hard to cover all of them | |||
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https://github.com/torvalds/linux/blob/master/drivers/input/touchscreen/elo.c | https://github.com/torvalds/linux/blob/master/drivers/input/touchscreen/elo.c | ||
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Revision as of 10:47, 29 March 2024
Types
http://en.wikipedia.org/wiki/Touchscreen#Technologies
Resistive
Capacitive
Capacitive sensing can sense anything that is capacitive (or somehow influences capacitance), which includes fingers or anything with a conductive tip - from specific styluses to sausages in latex gloves.
Designs usually try to only be sensitive to very nearby things (not far beyond a protective plastic/glass layer.
Has a few subtypes -- see capacitive sensing.
One of them can be multi-touch, and multi-touch tablets are very usually capacitive.
Capacitive touch can be faster and more responsive than resistive. Some of the simpler/cheaper designs are less accurate than resistive, though; some handwriting recognition stuck with resisitive).
The screen itself can be built in a more robust way than resistive (sensors are under the top glass, not part of the top layer as in resistive).
Went from there-but-specific (e.g. in trackpads) in the nineties to pretty common (in MP3 players, and phone touchscreens) in the late noughties.