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| My controller is branded Onetouch (taiwanese), specifically a 5W232-O. | | My controller is branded Onetouch (taiwanese), specifically a 5W232-O. |
| It uses basic 3-wire (RX,TX,Gnd) TTL-level RS232, at 9600 baud. | | : It uses basic TTL-level RS232, at 9600 baud. |
| The protocol's touch data comes in a simple 4-byte packet with a sync bit, packing two 12-bit coordinates, pen up/down information, and a checksum (found this in some PDF). | | : The protocol's touch data comes in a simple 4-byte packet with a sync bit, packing two 12-bit coordinates, pen up/down information, and a checksum (found this in some PDF) |
| A simple serial receive program can be used to check whether it works. | | : A simple serial receive program can be used to check whether it works. |
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| http://wiki.linuxmce.org/index.php/Egalax-Touchscreen | | http://wiki.linuxmce.org/index.php/Egalax-Touchscreen |
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| https://wiki.archlinux.org/index.php/touchscreen#Available_X11_drivers
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Revision as of 10:49, 29 March 2024
⚠ 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 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 ·
power supply considerations ·
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
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 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.
Optical
Acoustic
Temperature sensing
Brand-specific notes
Elo notes
Protocol notes
eGalax notes