Error: no matching function for call to 'TFT::text(String&, int, int)'

Projects Programming
1

I am getting this error message: "exit status 1
no matching function for call to 'TFT::text(String&, int, int)'"

I am not a professional and this is my biggest project yet. What am I doing wrong? Here is my code:

 //Libraries
#include <DHT.h>;
#include <TFT.h> // Hardware-specific library
#include <SPI.h>

//Constants
#define DHTPIN 6     // what pin we're connected to
#define DHTTYPE DHT22   // DHT 22  (AM2302)
#define CS   10
#define DC   9
#define RESET  8
DHT dht(DHTPIN, DHTTYPE); //// Initialize DHT sensor for normal 16mhz Arduino
TFT myScreen = TFT(CS, DC, RESET);


//Variables
int led = 7;
int chk;
float hum;  //Stores humidity value
float temp; //Stores temperature value
String screenHum = ""; //stores humidity in string
String screenTemp = ""; //stores temp in string

void setup()
{
    Serial.begin(9600);
  dht.begin();
  myScreen.begin();
  myScreen.background(0,0,0);  // clear the screen with black
  delay(1000);  // pause for dramatic effect

}

void loop()
{
    //Read data and store it to variables hum and temp
    hum = dht.readHumidity();
    temp= dht.readTemperature();
    //Print temp and humidity values to serial monitor
    Serial.print("Humidity: ");
    Serial.print(hum);
    Serial.print(" %, Temp: ");
    Serial.print(temp);
    Serial.println(" Celsius");
    if(hum < 70 && temp < 27){
      digitalWrite(led, HIGH);
    } else {
      digitalWrite(led, LOW);
    }
    //convert float to string
    screenHum.concat(hum);
    screenTemp.concat(temp);
    myScreen.stroke(255,0,255);
    myScreen.setTextSize(0);
    myScreen.setTextSize(2);
    myScreen.text("Humidity:",0,0);
    myScreen.text(screenHum,0,0);
    myScreen.text("%",0,0);
    
    myScreen.text(" %",0,0);
    delay(2000); //Delay 2 sec.
}

I am basically just trying to make a temperature & humidity monitor using the Arduino TFT screen.

2

This means that you can't use myScreen.text() function with String type. Convert your Strings to c-strings first:

myScreen.text(screenHum.c_str(),0,0);

But this is not the only mistake. For example, you create your screenHum string by concatenating a moisture value with them. The first time it will give the correct result - for example "55%". But you do it in a loop without clearing the old values. So then the new humidity values will stick to the old ones and the display will not be at all what you thought : "55%66%45%..."

3

Thank you, the code doesn't display any errors now, but the screen is just saying 30.37 and over and over like: 30.3730.3730.37 (I deleted the humidity and % text for testing purposes)

4

see my suggestion at the end of post 2

5

Thanks! So (a part of the) modified code now looks like this:

    screenHum.concat(hum);
    screenTemp.concat(temp);
    myScreen.stroke(255,0,255);
    myScreen.setTextSize(0);
    myScreen.setTextSize(2);
    
    myScreen.text(screenHum.c_str(),0,0);
    
    
    myScreen.text(" %",0,0);
    screenHum = "";
    screenTemp = "";
    delay(2000); //Delay 2 sec.

But the old and new values are still overlapping each other.

6

Please show your revised code in full

7

I didn't change anything else, i will but i can't right now

8

Hi again, here is the code:

 //Libraries
#include <DHT.h>;
#include <TFT.h> // Hardware-specific library
#include <SPI.h>

//Constants
#define DHTPIN 6     // what pin we're connected to
#define DHTTYPE DHT22   // DHT 22  (AM2302)
#define CS   10
#define DC   9
#define RESET  8
DHT dht(DHTPIN, DHTTYPE); //// Initialize DHT sensor for normal 16mhz Arduino
TFT myScreen = TFT(CS, DC, RESET);


//Variables
int led = 7;
int chk;
float hum;  //Stores humidity value
float temp; //Stores temperature value
String screenHum = ""; //stores humidity in string
String screenTemp = ""; //stores temp in string

void setup()
{
    Serial.begin(9600);
  dht.begin();
  myScreen.begin();
  myScreen.background(0,0,0);  // clear the screen with black
  delay(1000);  // pause for dramatic effect

}

void loop()
{
    //Read data and store it to variables hum and temp
    hum = dht.readHumidity();
    temp= dht.readTemperature();
    //Print temp and humidity values to serial monitor
    Serial.print("Humidity: ");
    Serial.print(hum);
    Serial.print(" %, Temp: ");
    Serial.print(temp);
    Serial.println(" Celsius");
    if(hum < 70 && temp < 27){
      digitalWrite(led, HIGH);
    } else {
      digitalWrite(led, LOW);
    }
    //convert float to string
    screenHum.concat(hum);
    screenTemp.concat(temp);
    myScreen.stroke(255,0,255);
    myScreen.setTextSize(0);
    myScreen.setTextSize(2);
    
    myScreen.text(screenHum.c_str(),0,0);
    
    
    myScreen.text(" %",0,0);
    screenHum = "";
    screenTemp = "";
    delay(2000); //Delay 2 sec.
}
9

What do you see in the screen with this code?

10

thanks for the help, I fixed it, I saw the numbers overlapping but I put in the line:

myScreen.background(0,0,0);

and that fixed my issue.

11

so please indicate the thread as solved