Questions tagged [touchscreen]

A display that incorporates a human interface device which records positional information of points of contact between the user and the display

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Adding backlight control for Raspberry Pi Zero 3.5 inch tft touch display (GPIO)

Can somebody please help me how i can modify TFT35 display for backlight control with PWM (Raspberry Pi Zero 2 - GPIO 18). I found one solution on GitHub (https://github.com/wild-mustango/VenusOsTFT35)...
Danster's user avatar
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Why does the air gap between the electrode and the overlay of a capacitive sensor have a negative impact on the touch performance?

I see in the design guidelines that the airgaps between the electrodes and the overlay of the capacitive sensor have detrimental effect on the performance of the touch sensor and they should be filled ...
Siddhesh's user avatar
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Measure capacitance on a mutual capacitive touch sensor

I interpret the mechanism of a mutual capacitive touch sensor like this: There are 2 electrodes X and Y. To measure the difference in capacity, the X electrode is driven high (i.e 3.3 V) and the Y ...
Maze2Go's user avatar
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I2C to USB converter with interrupt

I have a touch screen with I2C and interrupt output and I would like to connect this touch screen over a USB cable to a host controller. I know that it is possible to transfer interrupts on the USB ...
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Looking for a large capacitive touch array controller

I'm building a capacitive touch panel. It has an odd shape, so I resulted to building my own with the capacitive diamond array solution. It doesn't have a screen underneath, so it's all contained on a ...
Tamás Fehér's user avatar
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Have I configured the correct current supply for my TFT LCD Backlight?

I am currently working on a custom PCB which integrates a 3.5" TFT LCD. I am planning on driving the TFT backlight using a MIC4801 LED Driver and want to make sure I have configured the correct ...
henryv3's user avatar
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MIPI DSI touch screen compatibility with Orange Pi 5B

TD;DR Is DSI and MIPI D-PHY TX 4 lane the same thing? I came across a "Waveshare 7.9 touch display for Raspberry Pi" which has two options, HDMI and DSI. As I can see from Orange Pi's ...
44yu5h's user avatar
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technical term for this phenomenon: minor adjustments to a notebook's LED-LCD screen angle result in major legibility issues

Perhaps a bit of background will help you to understand the question I'm trying to formulate. I have no engineering background but would like to read more about this LED-LCD phenomenon though I don't ...
Tim's user avatar
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Can I run my 3.5" TFT backlight off of a 3.3V supply?

I just wanted to confirm my thoughts on the selection of resistor value for a 3.5" TFT screen I am working with. The datasheet gives a forward voltage of 3.2 V and a forward current of 120 mA. ...
henryv3's user avatar
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Need help understanding how capacitive touch sensor works

I watched this tutorial here (Explanation is from the time stamp 01:58 onwards): https://www.youtube.com/watch?v=3KQd9F0P6PI&t=283s and I'm having trouble understanding the concept. I get the ...
Yeo's user avatar
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Capacitive touch: Board penetrations

If I place copper pads (for use as self-capacitance capacitive touch buttons) on the secondary side of a board and place adjacent to them surface-mount bottom-facing LEDs on the primary side of the ...
kando's user avatar
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Capacitive touch: Multi-touch (Simultaneous Read) Self-capacitance Buttons with Single Capacitive Touch Interface IC

With capacitive touch, if I want multiple independent buttons rather than a screen, will multi-touch (ability to register more than one button simultaneously) still be prevented with self-capacitance ...
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Need advice on tapping into touch screen connected to LCD

I'm hoping to get some advice on a technical issue I'm currently facing. I am attempting to tap into a touch screen that is connected to an LCD, but I'm feeling a bit confused about how to proceed. ...
Jonas's user avatar
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Voltage triangulation across a copper plate for touch sensing

I'm using an Arduino Uno and am admittedly a bit out of my depth here. I'm trying to sense (very broadly) where on a copper plate a touch occurs. I'm using the voltage triangulation method found here. ...
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Power supply for Raspberry Pi Zero with 2 seconds delay

I'm building a small touch screen which will sport a Raspberry PI Zero inside the monitor. The screen is powered by a 12 V external power supply. To power the RP Zero I use an L7805ACV voltage ...
smoczyna's user avatar
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Touch screen creating spikes on power supply / ground

Per the title, we have a 7" TFT with a Goodix GT911 touchscreen controller which connects on a small FPC (power, ground, I2C and RST/INT lines), however when the touch controller is operational ...
John U's user avatar
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What CAD software is used to design and manufacture projected capacitive touchscreens?

I am looking to learn more about how projected capacitive (PCAP) touchscreens are designed and made, specifically with laser ablation. What kind of CAD software is used to create layered drawings for ...
Thien Ho's user avatar
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How can I make a beer glass to be detected by a touchscreen?

I know this sounds weird, but hear me out. I was planning to build a FSR system on Arduino that detects when a beer glass is lifted off and slammed back on the coaster, showing the elapsed chug time ...
TheJasonist's user avatar
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Do projected capacitive touch panels need side clearance to ground metal?

I need to use a TFT module with an integrated capacitive touch. The TFT has it's FFC and the touch controller has its own, with power supply and an I2C interface. Quite standard, I think, since every ...
Lorenzo Marcantonio's user avatar
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How do self capacitance touch screens work?

I get how mutual capacitance touch screens work, by changing the dielectric around the pairs of electrode and "stealing" electric field lines. Connection to earth of the object (a finger ...
Jonas Daverio's user avatar
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Using capacitive touch screen without human hand

I'm trying to learn more about how to engage a capacitive touchscreen without using a human finger. Full disclaimer I'm in mechanical engineering (notoriously known to have difficulty comprehending ...
Buffoon's user avatar
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3 votes
1 answer
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How do capacitive touchscreens really work?

I have a bit of trouble understanding the electrical laws which apply when I touch a capacitive touchscreen with my finger. Apparently, there is an electric current running through electrodes below ...
JackOfHearts's user avatar
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Advice for where to start when choosing and working with a touch screen display for the first time [closed]

I am looking to utilize a touch screen display in an ongoing project and have not ever had to use one before so I am starting from ground zero. I was hoping to get some general advice on what to start ...
jakob's user avatar
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How to detect which finger touched the mobile screen [closed]

I'm working on a project where I need to detect which finger touched the mobile screen i.e capacitive screen. I'm not talking about double finger touch or single or drag and move etc. I'm asking which ...
Vikas Acharya's user avatar
1 vote
3 answers
2k views

Bad capacitive touch screen sensitivity when running on battery, without earth

In short: I´m working on a battery driven handheld device with capacitive-touch screen. The capacitive-touch works perfect when the PCB connected via USB, but it loses sensitivity when driven by ...
Dr_Smu's user avatar
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1 answer
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what this is smd sot23-6 marking code 63

i need help. I have problem with resistive touchscreen 4 wire, I've replaced with a new touchscreen but it still doesn't work. Capacitor & other part around ic is normal. I think this ic damage. ...
user255512's user avatar
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Why doesn't my phone scroll if I place a ring on the screen?

(Full disclosure — I posted this first on Physics SE and it was suggested it might be a better fit here.) If I place a ring on the screen of my phone, and then try to scroll with my finger inside the ...
BeginTheBeguine's user avatar
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Making a hole in a computer touch screen

I have just replaced the touch screen on my HP laptop. All works well but the opening for the camera on the new touch screen is offset a bit from the original. Hence the camera is looking through ...
Kevin's user avatar
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5 votes
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Difference between LVDS, MIPI, DPI and DSI

I'm on a project that involves TFT displays and Raspberry Pi Compute Module 4. I noticed that there are several acronyms, protocols confusing information. As I understand it, there are protocols: DBI:...
Cristian Pastro's user avatar
3 votes
1 answer
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How exactly does the Apple Pencil work?

I have a few questions regarding the technical details of the Apple Pencil: How does the iPad differentiate between the Pencil and your hand (palm rejection)? Is the Pencil creating some sort of a ...
Amplify's user avatar
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Touch screen power supply problem

I am using Raspberry PI 4 Model B (4GB) with an official capacitive 7" display. I am powering the device using an external AC-DC (220VAC - 12V) power supply. I converter 12V to 5V using a buck ...
Eugen's user avatar
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How to implement a touch controller wake up circuit?

I have an system-on-module (SoM) connected to an LCD with touchscreen interface. The SoM allows wake up from sleep by toggling one of its GPIOs. These are the datasheets: LCD, touch controller and SoM....
Cristian M's user avatar
1 vote
1 answer
142 views

Identify Ecobee's 4/5 screens pinouts

Got myself few broken Ecobees thermostats thought to reuse some of the parts in my Arduino/STM32 projects. The question is how to identify screen pinout. I have few working Ecobees and oscilloscope ...
Ilia Rebane's user avatar
2 votes
2 answers
587 views

How do I calculate the capacitance of a capacitive touch or water sensor?

Sensors like capacitive touch or moisture sensors are simply two traces drawn on a PCB. For example, you may check the Grove soil moisture sensor. In these types of sensors, the capacitance increases ...
Sadat Rafi's user avatar
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Touch pad Document

I tear down one touch pad and wonder what technology they used. I am sharing picture of it. Any one know what is used for touch sense ? (my guess is capacitive). I am planning to design one by myself. ...
Dharmik Prajapati's user avatar
1 vote
1 answer
133 views

How to detect which pins on a pin display are touched using capacitive sensing

I'm working on a project to apply touch sensitivity to a modified pin display (30x30). The goal is to allow someone to interact with the display through their fingers and ideally touch. We initially ...
aheigins's user avatar
0 votes
2 answers
57 views

Need help with configuration of a touch sensing lamp project! [closed]

I am currently a design student in university, and am attempting to configure a large scale project for my final. The idea is that there would be a lamp, with one person holding onto either (wire? ...
Maxwell Fisher's user avatar
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2 answers
1k views

Will using the positive end of an AA battery to touch my phone screen damage my phone? [closed]

I'm playing a game where it will be helpful to hold down a button for an extended period of time. I didn't have a stylus, so I looked online for any ideas. Lots of people said to use the negative end ...
Peter021's user avatar
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1 answer
736 views

Test device for capacitive touch screens?

Are there any (more or less) simple test devices for capacitive touch screens, e.g. something which I can attach to a touch screen and which is able to do capacitive inputs at fixed locations (ideally,...
MRalwasser's user avatar
1 vote
1 answer
185 views

How to redirect electric field lines with a copper plane

I have been testing a capacitive sensing circuit in which an electric field is projected vertically to sense a finger (a grounded conductive object). On the PCB, a tx and an rx are 2 copper structures ...
JCSB's user avatar
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1 vote
2 answers
454 views

Is the phantom touch issue present in resistive touch screens?

Do phantom touches (ghost touches) occur in resistive touch screens, or are they only present in capacitive touch screen displays?
hiten chauhan's user avatar
2 votes
1 answer
2k views

Reverse-engineer pinout of capacitive touchscreen

I'm interested in reusing the capacitive touchscreen of my old iPad. (As a learning experience -- I'm aware that this project will cost me more than just buying a new capacitive touchscreen would.) ...
Evan Krall's user avatar
1 vote
2 answers
780 views

How to get USB-mouse output from capacitive touch panel?

I have this 7" capacitive touch panel overlay that I want to attach to my Raspberry Pi 4B. I don't know what kind of data comes out of that FPC cable, or even what its pinout is. Is there a well-...
chocolate's user avatar
-2 votes
2 answers
82 views

Capacitive touchscreens dangerous and piezoelectric [closed]

Isn't capacitive touchscreen dangerous? I mean we are using our body to be a conductor and even with small voltages a current that could kill us. Also why aren't piezoelectric touchscreens used? In ...
Se1fie's user avatar
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1 vote
0 answers
47 views

Cell Phone Purse w/ Touch Screen Easy Access

Hi I want to make Cell Phone Purse w/ Touch Screen Easy Access in mass production . My question, what is the quality of plastic which used window in front of cellphone which is touch screen . Thanks
Bijan Gharai's user avatar
-1 votes
1 answer
323 views

Small touch screen that works under frosted glass or plastic [closed]

I’m trying to build a device with an rpi 3b+ with a touch screen that looks something like the nest thermostat e. Is it possible to have a touchscreen behind frosted glass or can anyone let me know ...
Astronaako's user avatar
1 vote
1 answer
208 views

A hole in middle of a capacitive touch screen

I'm thinking about using a capacitive touch screen (the touch layer only, no display) to detect the position of two moving parts. Each part would have its 'stylus' just above the screen to mark the ...
Josef Kufner's user avatar
1 vote
0 answers
96 views

Is there definitive documentation regarding the reliability of a capacitive touchscreen?

I'm working with a manufacturer who wants to use a touchscreen (like a mobile phone) to activate the machinery but is afraid the touchscreen could give a false reading. This would be a touch-and-hold ...
TopherC's user avatar
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2 votes
1 answer
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Why does this part of an OLED filter light only when orientated correctly?

Note: The screen is an OLED screen. I had assumed it was LCD, therefore the post mentions it as such. I was disassembling a Samsung phone (GT-I9305) and was able to seperate the LCD into two sections....
Lachlan Etherton's user avatar
-2 votes
1 answer
103 views

How can I add a raspberry to a touchscreen car dvd unit? [closed]

I am working on converting a Toyota 2-din touch screen dvd stereo unit into a car computer. I would like to add a raspberry to it and be able to have the raspberry display a browser on the touch ...
James Okwudili Agada's user avatar

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