Humidity sensor using DHT11 Temp Sensor

Projects Programming
1

I keep getting issues in my DHT11 Temp sensor setup. My aim is to build a touchscreen that would give us the the amount of humidity in the area using a DHT11 Temp sensor.

Here is my code:

#if 1

#include <Adafruit_GFX.h>
#include <MCUFRIEND_kbv.h>
MCUFRIEND_kbv tft;
#include <TouchScreen.h>
#define MINPRESSURE 200
#define MAXPRESSURE 1000

// ALL Touch panels and wiring is DIFFERENT
// copy-paste results from TouchScreen_Calibr_native.ino
// Sample const int XP = 6, XM = A2, YP = A1, YM = 7; //ID=0x9341
// Sample const int TS_LEFT = 907, TS_RT = 136, TS_TOP = 942, TS_BOT = 139;

//Data from TouchScreen_Calibr_native
const int XP=8,XM=A2,YP=A3,YM=9; //240x320 ID=0x9595
const int TS_LEFT=891,TS_RT=108,TS_TOP=101,TS_BOT=912;

TouchScreen ts = TouchScreen(XP, YP, XM, YM, 300);

Adafruit_GFX_Button temp_btn, humidity_btn, moisture_btn;

int pixel_x, pixel_y;     //Touch_getXY() updates global vars
bool Touch_getXY(void)
{
    TSPoint p = ts.getPoint();
    pinMode(YP, OUTPUT);      //restore shared pins
    pinMode(XM, OUTPUT);
    digitalWrite(YP, HIGH);   //because TFT control pins
    digitalWrite(XM, HIGH);
    bool pressed = (p.z > MINPRESSURE && p.z < MAXPRESSURE);
    if (pressed) {
        pixel_x = map(p.x, TS_LEFT, TS_RT, 0, tft.width()); //.kbv makes sense to me
        pixel_y = map(p.y, TS_TOP, TS_BOT, 0, tft.height());
    }
    return pressed;
}

#define BLACK   0x0000
#define BLUE    0x001F
#define RED     0xF800
#define GREEN   0x07E0
#define CYAN    0x07FF
#define MAGENTA 0xF81F
#define YELLOW  0xFFE0
#define WHITE   0xFFFF


//https://create.arduino.cc/projecthub/techno_z/dht11-temperature-humidity-sensor-98b03b

//Sensor
#include <DHT.h>
#include <DHT_U.h>
#define dht_apin A5 // Analog Pin sensor is connected to
DHT;
 

void setup(void)
{
    //Sensor
    Serial.begin(9600);
    delay(500);//Delay to let system boot
    Serial.println("DHT11 Humidity & temperature Sensor\n\n");
    delay(1000);//Wait before accessing Sensor
    
    
    uint16_t ID = tft.readID();
    Serial.print("TFT ID = 0x");
    Serial.println(ID, HEX);
    Serial.println("Calibrate for your Touch Panel");
    if (ID == 0xD3D3) ID = 0x9486; // write-only shield
    tft.begin(ID);
    tft.setRotation(0);            //PORTRAIT
    tft.fillScreen(BLACK);
    
    temp_btn.initButton(&tft,  60, 200, 100, 40, WHITE, CYAN, BLACK, "TEMP", 2);
    humidity_btn.initButton(&tft, 180, 200, 100, 40, WHITE, CYAN, BLACK, "HUMIDITY", 2);
   // moisture_btn.initButton(&tft, 100, 240, 140, 40, WHITE, CYAN, BLACK, "MOISTURE", 2);
    moisture_btn.initButton(&tft, 120, 260, 140, 40, WHITE, CYAN, BLACK, "MOISTURE", 2);
     
    temp_btn.drawButton(false);
    humidity_btn.drawButton(false);
    moisture_btn.drawButton(false);
    
    tft.fillRect(40, 40, 160, 80, WHITE);
    tft.setCursor(75, 50);
    tft.setTextColor(GREEN);
    tft.setTextSize(3);
    tft.println("Home");
    tft.setCursor(60, 80);
    tft.print("Screen"); 
   
}

/* two buttons are quite simple
 */
void loop(void)
{
    //Sensor
    dht.read11( dht_apin );
    Serial.print("Current humidity = ");
    Serial.print(dht.humidity);
    Serial.print("%  ");
    Serial.print("temperature = ");
    Serial.print(dht.temperature); 
    Serial.println("C  ");
    
    delay(1000);//Wait 1 second before accessing sensor again.

    
    bool down = Touch_getXY();
    temp_btn.press(down && temp_btn.contains(pixel_x, pixel_y));
    humidity_btn.press(down && humidity_btn.contains(pixel_x, pixel_y));
    moisture_btn.press(down && moisture_btn.contains(pixel_x, pixel_y));
     
    if (temp_btn.justReleased())
        temp_btn.drawButton();
    if (humidity_btn.justReleased())
        humidity_btn.drawButton();
    if (moisture_btn.justReleased())
        moisture_btn.drawButton();
            
    if (temp_btn.justPressed()) {
        temp_btn.drawButton(true);
        tft.fillRect(40, 40, 160, 80, RED);
        tft.setCursor(55, 65);
        tft.setTextColor(BLACK);
        tft.setTextSize(4);
        tft.print(dht.temperature);
    }
    if (humidity_btn.justPressed()) {
        humidity_btn.drawButton(true);
        tft.fillRect(40, 40, 160, 80, GREEN);
        tft.setCursor(55, 65);
        tft.setTextColor(BLACK);
        tft.setTextSize(4);
        tft.print(dht.humidity);
    }

    if (moisture_btn.justPressed()) {
       moisture_btn.drawButton(true);
       tft.fillRect(40, 40, 160, 80, BLUE);
    }
}
#endif
2

The error was on this line:

dht.read11( dht_apin );

The error message said:

Compilation Error: 'dht' was not declared in this scope

3

This line should be

DHT dht; // declare a DHT object

The reason the error was here (below) is because you had not declared a DHT object/instance.

4

Thanks

5

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