How to turn 2.8" TFT On/Off while leaving Resistive Touchscr

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paDoug
 
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How to turn 2.8" TFT On/Off while leaving Resistive Touchscr

Post by paDoug »

I am new to Arduino, so just getting started. I have the 2.8" TFT LCD with MicroSD and Resistive Touchscreen. What I would like to do is have the LCD normally be off,..then when someone touches the screen the resistive overlay will detect a touch, and turn on the screen. Which will remain on until a timeout of inactivity occurs.

Is this doable on this board? Ie, can I separate the power feeds leaving the resistive screen on, while the LCD is off? Also, for turning on/off the LCD - what is the right way to do this? Add a transistor on the 5Vin triggered by a digital pin? Or, Can I just use a Digital Pin directly for the power instead of the 5V direct power source?

Thanks in advance for the help.

Parts:
Arduino UNO
2.8" TFT LCD with Touchscreen Breakout board w/MicroSD Socket
Connecting using SPI Method

paDoug

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metaphorz
 
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Re: How to turn 2.8" TFT On/Off while leaving Resistive Touc

Post by metaphorz »

I just posted on the same hardware. There are two .ino (Arduino) sketches in the github
repository for this display. Have you been able to get either of them to compile in the
Arduino IDE?

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paDoug
 
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Re: How to turn 2.8" TFT On/Off while leaving Resistive Touc

Post by paDoug »

I was able to get all the projects downloaded from adafruit to work,,,including the screen test, touch sample (drawing), as well as the debut project (shows du coordinates of touches).

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adafruit_support_mike
 
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Re: How to turn 2.8" TFT On/Off while leaving Resistive Touc

Post by adafruit_support_mike »

The shield is designed so it's possible to control the TFT's backlight, but "always on" is the default.

To control the backlight you need to put a solder bridge across a pair of pads on the bottom of the PCB. That will connect pin 3 to the backlight control. A more complete description lives on this page of the tutorial:

https://learn.adafruit.com/adafruit-2-8 ... -touch-irq

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metaphorz
 
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Re: How to turn 2.8" TFT On/Off while leaving Resistive Touc

Post by metaphorz »

It is not that I want to control the backlight, but rather, I am expecting
that running the demo programs and downloading them will do something
other than show a backlight (only) -- no graphics, nothing moving or
displayed on the screen.

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paDoug
 
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Re: How to turn 2.8" TFT On/Off while leaving Resistive Touc

Post by paDoug »

adafruit_support_mike wrote:The shield is designed so it's possible to control the TFT's backlight, but "always on" is the default.

To control the backlight you need to put a solder bridge across a pair of pads on the bottom of the PCB. That will connect pin 3 to the backlight control. A more complete description lives on this page of the tutorial:

https://learn.adafruit.com/adafruit-2-8 ... -touch-irq
Thank you for this reply...but it didn't actually answer my question. I had already found these instructions - the question is how do I leave the resistive screen on while turning off the LCD? OR did your post imply that if I do the solder method that the resistive screen will still function when I turn off the LCD with this method?

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paDoug
 
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Re: How to turn 2.8" TFT On/Off while leaving Resistive Touc

Post by paDoug »

metaphorz wrote:It is not that I want to control the backlight, but rather, I am expecting
that running the demo programs and downloading them will do something
other than show a backlight (only) -- no graphics, nothing moving or
displayed on the screen.
I'd imagine you have some of the control wires improperly connected? Or...actually...I found that the instructions for wiring didn't match the actual code for the pins used. So just check that the Analog pins you are connected to actually match the wired pins on the breadboard. Also, the serial monitor shows diagnostics on startup.

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paDoug
 
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Re: How to turn 2.8" TFT On/Off while leaving Resistive Touc

Post by paDoug »

adafruit_support_mike...can you possibly look at my last post and reply to the question? I'm not sure you answered my original post.

Thanks!

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metaphorz
 
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Re: How to turn 2.8" TFT On/Off while leaving Resistive Touc

Post by metaphorz »

@paDoug: for my case, I am using the 2.8" TFT shield so there are no wires.
It just fits cleanly over the Uno. I am assuming that power to the LCD comes
from the USB port (maybe a bad assumption?). I did have to enable this
in Adafruit_TFTLCD.h: #define USE_ADAFRUIT_SHIELD_PINOUT, which is
acknowledged in the Serial monitor, along with an unknown driver chip:

TFT LCD test
Using Adafruit 2.8" TFT Arduino Shield Pinout
TFT size is 240x320
Unknown LCD driver chip: 1010

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metaphorz
 
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Re: How to turn 2.8" TFT On/Off while leaving Resistive Touc

Post by metaphorz »

@paDoug: Got it sorted out and explained on the other thread. The problem was
that I needed the ILI9341 and FT6206 libraries and not the generic TFTLCD
library.

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adafruit_support_mike
 
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Re: How to turn 2.8" TFT On/Off while leaving Resistive Touc

Post by adafruit_support_mike »

paDoug wrote:OR did your post imply that if I do the solder method that the resistive screen will still function when I turn off the LCD with this method?
The touchscreen will still work when the LED backlight is turned off.

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