Electronics notes/Touch screen notes

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⚠ This is for beginners and very much by a beginner / hobbyist

It's intended to get an intuitive overview for hobbyist needs. It may get you started, but to be able to do anything remotely clever, follow a proper course or read a good book.


Some basics and reference: Volts, amps, energy, power · batteries · resistors · transistors · fuses · diodes · capacitors · inductors and transformers · ground

Slightly less basic: amplifier notes · varistors · changing voltage · baluns · frequency generation · Transmission lines · skin effect


And some more applied stuff:

IO: Input and output pins · wired local IO · wired local-ish IO · ·  Various wireless · 802.11 (WiFi) · cell phone

Sensors: General sensor notes, voltage and current sensing · Knobs and dials · Pressure sensing · Temperature sensing · humidity sensing · Light sensing · Movement sensing · Capacitive sensing · Touch screen notes

Actuators: General actuator notes, circuit protection · Motors and servos · Solenoids

Noise stuff: Stray signals and noise · sound-related noise names · electronic non-coupled noise names · electronic coupled noise · ground loop · strategies to avoid coupled noise · Sampling, reproduction, and transmission distortions

Audio and video notes: See avnotes


Platform specific

Arduino and AVR notes · (Ethernet)
Microcontroller and computer platforms ··· ESP series notes · STM32 series notes


Less sorted: Ground · device voltage and impedance (+ audio-specific) · electricity and humans · Common terms, useful basics, soldering · landline phones · pulse modulation · signal reflection · Project boxes · resource metering · SDR · PLL · vacuum tubes · Multimeter notes Unsorted stuff

Some stuff I've messed with: Avrusb500v2 · GPS · Hilo GPRS · JY-MCU · DMX · Thermal printer ·

See also Category:Electronics.

Types

http://en.wikipedia.org/wiki/Touchscreen#Technologies


Resistive

This article/section is a stub — some half-sorted notes, not necessarily checked, not necessarily correct. Feel free to ignore, or tell me about it.

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

This article/section is a stub — some half-sorted notes, not necessarily checked, not necessarily correct. Feel free to ignore, or tell me about it.

Capacitive sensing can sense various materials nearby, which includes fingers or anything with a conductive tip - from specific styluses to sausages in latex gloves.

Designs usually focus on a specific range of capacitive effect, and will then respond fewer things that aren't fingers and closeby.


Capacitive tricks went from being there in only a few devices (e.g. nineties trackpads) to increasingly common (in MP3 players, and phone touchscreens) in the late noughties, to uniquitous in phones and tablets since.


Has a few subtypes -- see capacitive sensing.

One of them can be multi-touch, and multi-touch tablets and phones are very usually capacitive.


Capactive touchscreens 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).

Capacitive touch can also be faster and more responsive than resistive. Some of the simpler/cheaper designs are less accurate than resistive, though; some handwriting recognition devices actually stuck with resisitive.

Optical

Acoustic

Temperature sensing

Brand-specific notes

Elo notes

Protocol notes

eGalax notes