Resistive touchscreen display not working with arduino

davidlukash · July 2, 2022, 11:49am

I recently bought a tft display with a touch panel built in but I cant seem to get the touchscreen part of it working. This is the link to the display www.amazon.co.uk/dp/B07PNQFSKN?ref=ppx_pop_mob_ap_share and this is my code (it does include code from other people)

#include <MCUFRIEND_kbv.h> 
#include <Adafruit_GFX.h>
MCUFRIEND_kbv tft;
#include <TouchScreen.h>
#include <FreeDefaultFonts.h>
const int XP=9,XM=A3,YP=A3,YM=8;
const int TS_LEFT=907,TS_RT=136,TS_TOP=942,TS_BOT=139;

TouchScreen ts = TouchScreen(XP, YP, XM, YM, 300);
TSPoint tp;
#define BLACK 0x0000
#define NAVY 0x000F
#define DARKGREEN 0x03E0
#define DARKCYAN 0x03EF
#define MAROON 0x7800
#define PURPLE 0x780F
#define OLIVE 0x7BE0
#define LIGHTGREY 0xFFFF
#define DARKGREY 0x7BEF
#define BLUE 0x001F
#define GREEN 0x07E0
#define CYAN 0x07FF
#define RED 0xF800
#define MAGENTA 0xF81F
#define YELLOW 0xFFE0
#define WHITE 0xFFFF
#define ORANGE 0xFD20
#define GREENYELLOW 0xAFE5

void setup(void)
{
  Serial.begin(9600);
  uint16_t ID = tft.readID();
  Serial.println(ID);
  Serial.println(tft.width());
  Serial.println(tft.height());
  if (ID == 0xD3) ID = 0x9481;
  tft.begin(ID);
  tft.setRotation(0);
  int h = 0;
  int m = 0;
  int s = 0;
  tft.fillScreen(BLACK);
  tft.setFont(&FreeSevenSegNumFont);
  tft.setTextSize(1.5);
  tft.setCursor(-15, 55);
  tft.print("1234");
  int r = 101;
  int ws = 10;
  while (ws != 0){
    tft.drawFastHLine(0 , r , 320 , WHITE);
    ws = ws - 1;
    r = r + 1;
  }
  tft.drawRect(0, 112, 320, 380, BLUE);
  tft.fillRect(0, 112, 320, 380, BLUE);

  tft.drawRoundRect(22, 137, 50, 50, 10, LIGHTGREY);
  tft.fillRoundRect(22, 137, 50, 50, 10, LIGHTGREY);

  tft.drawRoundRect(97, 137, 50, 50, 10, LIGHTGREY);
  tft.fillRoundRect(97, 137, 50, 50, 10, LIGHTGREY); 

  tft.drawRoundRect(172, 137, 50, 50, 10, LIGHTGREY);
  tft.fillRoundRect(172, 137, 50, 50, 10, LIGHTGREY);

  tft.drawRoundRect(247, 137, 50, 50, 10, LIGHTGREY);
  tft.fillRoundRect(247, 137, 50, 50, 10, LIGHTGREY);   


  tft.drawRoundRect(22, 212, 50, 50, 10, LIGHTGREY);
  tft.fillRoundRect(22, 212, 50, 50, 10, LIGHTGREY);

  tft.drawRoundRect(97, 212, 50, 50, 10, LIGHTGREY);
  tft.fillRoundRect(97, 212, 50, 50, 10, LIGHTGREY);

  tft.drawRoundRect(172, 212, 50, 50, 10, LIGHTGREY);
  tft.fillRoundRect(172, 212, 50, 50, 10, LIGHTGREY);

  tft.drawRoundRect(247, 212, 50, 50, 10, LIGHTGREY);
  tft.fillRoundRect(247, 212, 50, 50, 10, LIGHTGREY);


  tft.drawRoundRect(22, 287, 50, 50, 10, LIGHTGREY);
  tft.fillRoundRect(22, 287, 50, 50, 10, LIGHTGREY);

  tft.drawRoundRect(97, 287, 50, 50, 10, LIGHTGREY);
  tft.fillRoundRect(97, 287, 50, 50, 10, LIGHTGREY); 

  tft.drawRoundRect(172, 287, 50, 50, 10, LIGHTGREY);
  tft.fillRoundRect(172, 287, 50, 50, 10, LIGHTGREY);

  tft.drawRoundRect(247, 287, 50, 50, 10, LIGHTGREY);
  tft.fillRoundRect(247, 287, 50, 50, 10, LIGHTGREY); 

  tft.drawRoundRect(97, 362, 50, 50, 10, LIGHTGREY);
  tft.fillRoundRect(97, 362, 50, 50, 10, LIGHTGREY); 

  tft.drawRoundRect(247, 362, 50, 50, 10, LIGHTGREY);
  tft.fillRoundRect(247, 362, 50, 50, 10, LIGHTGREY);


  tft.drawRoundRect(25, 427, 272, 30, 10, LIGHTGREY);
  tft.fillRoundRect(25, 427, 272, 30, 10, LIGHTGREY);

  tft.setTextColor(0x2945);

  tft.setFont(&FreeSevenSegNumFont);
  tft.setTextSize(1.5);
  tft.setCursor(20, 187);
  tft.print("1");
  tft.setCursor(105, 187);
  tft.print("2");
  tft.setCursor(180, 187);
  tft.print("3");
  tft.setFont(NULL);
  tft.setTextSize(5);
  tft.setCursor(257, 144);
  tft.print("+");

  tft.setFont(&FreeSevenSegNumFont);
  tft.setTextSize(1.5);
  tft.setCursor(28, 263);
  tft.print("4");
  tft.setCursor(105, 263);
  tft.print("5");
  tft.setCursor(180, 263);
  tft.print("6");
  tft.setFont(NULL);
  tft.setTextSize(5);
  tft.setCursor(259, 220);
  tft.print("-");

  tft.setFont(&FreeSevenSegNumFont);
  tft.setTextSize(1.5);
  tft.setCursor(28, 338);
  tft.print("7");
  tft.setCursor(105, 338);
  tft.print("8");
  tft.setCursor(180, 338);
  tft.print("9");
  tft.setFont(NULL);
  tft.setTextSize(5);
  tft.setCursor(259, 295);
  tft.print("*");

  tft.setFont(&FreeSevenSegNumFont);
  tft.setTextSize(1.5);
  tft.setCursor(106, 412);
  tft.print("0");
  tft.setFont(NULL);
  tft.setTextSize(5);
  tft.setCursor(258, 370);
  tft.print("/");

  tft.setCursor(80, 430);
  tft.setFont(NULL);
  tft.setTextSize(3.5);
  tft.print("Calculate");
}

void loop(void)
{
  tp = ts.getPoint();
  int x = tp.x;
  int y = tp.y;
  if (tp.z > 24400){
    Serial.println("x: " + String(x) + " y: " + String(y));
    delay(10);
  }
  if (tp.z > 24400 and ((x < 72 and x > 22) and (y < 187 and y > 137))){
    tft.fillScreen(RED);
    delay(10);
  }
}

davidlukash · July 2, 2022, 11:50am

I'm trying to make a simple calculator

anon57585045 · July 2, 2022, 11:52am

Have you tried running the display library example sketches? When you say it's not working, it's vague. Please describe the non-working exactly.

davidlukash · July 2, 2022, 11:57am

Yes I have and what I mean by not working is that in this section of the code

tp = ts.getPoint();
  int x = tp.x;
  int y = tp.y;
  if (tp.z > 24400){
    Serial.println("x: " + String(x) + " y: " + String(y));
    delay(10);
  }

it is supposed to print out the x and y values to the serial port however it doesn't

anon57585045 · July 2, 2022, 11:57am

...and what happens instead?

davidlukash · July 2, 2022, 11:58am

it doesn't print out anything to the serial port but in the start of the code it does print out the width and height so I suspect it is a problem with the code

anon57585045 · July 2, 2022, 11:59am

Did you try a serial debug print of 'tp,z'? If the value is <= 24400, nothing will print.

davidlukash · July 2, 2022, 12:00pm

I will try that now

davidlukash · July 2, 2022, 12:02pm

My code is not very efficient but here it is

{
  void loop(void){
  tp = ts.getPoint();
  int x = tp.x;
  int y = tp.y;
  Serial.println("z: " + tp.z);
  delay(10);
}

It just prints out z: constantly to the serial port with no value
it does have the whole entire other segment of the code

anon57585045 · July 2, 2022, 12:04pm

You screwed it up. println() can only print one value. You forgot the abominable String conversion.

davidlukash · July 2, 2022, 12:05pm

oh okay i will change it

anon57585045 · July 2, 2022, 12:05pm

Do you understand this code at all? What is the significance of the magic number '24400'?

davidlukash · July 2, 2022, 12:07pm

It used to work before but it gave incorrect x and y values and I noticed that if the number was below 24400 it kept printing out the x and y values of where the most pressure is applied

anon57585045 · July 2, 2022, 12:10pm

I'm sorry, you have not answered several of my questions directly. Someone else will have to help you. Good luck.

david_prentice · July 2, 2022, 1:51pm

Yes, these Blue 3.5 inch shields often have Touch pins on 9, A3, A2, 8.
No, you can't have A3 , A3. i.e. two ADC with the same pin.

From examples.

#define MINPRESSURE 200
#define MAXPRESSURE 1000
...
    tp = ts.getPoint();   //tp.x, tp.y are ADC values

    // if sharing pins, you'll need to fix the directions of the touchscreen pins
    pinMode(XM, OUTPUT);
    pinMode(YP, OUTPUT);
    // we have some minimum pressure we consider 'valid'
    // pressure of 0 means no pressing!

    if (tp.z > MINPRESSURE && tp.z < MAXPRESSURE) {

You will never get 24400 from a valid touch. You will never get x < 72 when TS_RT=136. It is possible to get y < 187 when TS_BOT=139.

The Library comes with a whole set of examples. Run all of the examples before you ever think of writing your own sketches.

David.

davidlukash · July 3, 2022, 4:49pm

Thank you for replying with this information I will try it now

davidlukash · July 3, 2022, 6:13pm

I ran one of the examples labelled "diagnose_Touchpins" this gave me the XM , XP , YP , YM values for my display then I deleted this const int TS_LEFT=907,TS_RT=136,TS_TOP=942,TS_BOT=139; part of the code since I didn't think it wouldn't affect the functioning of the code (It didn't). In the void loop part of the code I put

if ((tp.z > 350 and tp.z < 1000) or tp.z == 0){
    Serial.print("X: ");
    Serial.print(String(tp.x));
    Serial.print(" Y: ");
    Serial.println(String(tp.y));
  }
  else{
    Serial.print("Z: ");
    Serial.println(String(tp.z));
  }

and I ran some tests such as changing the minimum pressure and maximum pressure and I worked out the values for my specific screen then I ran some tests again to print 1 to the serial when 1 on the screen was pressed and it worked thank you for your help @david_prentice

system · December 30, 2022, 6:14pm

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Resistive touchscreen display not working with arduino

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