Electronics notes/Touch screen notes: Difference between revisions
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Most simpler touch screens are resistive. | Most simpler touch screens are resistive. | ||
For a good time they were the rather cheaper option -- largely though economy of scale. | For a good time they were the rather cheaper option -- largely though economy of scale. | ||
They need force, and may require a stylus to be useful. | They need more force than the later capacitive type, and may require a stylus to be useful. | ||
Each axis, when touched, will give a particular resistance in a range (usually interfaced with an ADC), so can report only a single touch - touching on multiple places (e.g. resting a palm while drawing) will mis-report. | ''Can'' have pretty decent resolution, but may not. | ||
Each axis, when touched, will give a particular resistance in a range (usually interfaced with an ADC), so can report only a '''single touch''' - touching on multiple places (e.g. resting a palm while drawing) will typically mis-report. | |||
There's 4-wire, 5-wire, 7-wire, 8-wire and more. | There's 4-wire, 5-wire, 7-wire, 8-wire and more. | ||
These relate to different accuracies, and some to variants that won't lose as much accuracy over time{{verfiy}} | These relate to different accuracies, and some to variants that won't lose as much accuracy over time{{verfiy}} | ||
====Capacitive==== | ====Capacitive==== |
Revision as of 10:54, 29 March 2024
Types
http://en.wikipedia.org/wiki/Touchscreen#Technologies
Resistive
Most simpler touch screens are resistive. For a good time they were the rather cheaper option -- largely though economy of scale.
They need more force than the later capacitive type, and may require a stylus to be useful.
Can have pretty decent resolution, but may not.
Each axis, when touched, will give a particular resistance in a range (usually interfaced with an ADC), so can report only a single touch - touching on multiple places (e.g. resting a palm while drawing) will typically mis-report.
There's 4-wire, 5-wire, 7-wire, 8-wire and more.
These relate to different accuracies, and some to variants that won't lose as much accuracy over timeTemplate:Verfiy
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.