I am getting a error (dht does not name a type)

larenzia93 · July 19, 2023, 2:23pm

Hello

i am getting a error (dht does not name a type) I downloaded the library dht and adafruit unified sensor and still dont work

board arduino mega
dht.11 sensor with 3 pins

C:\Users\Jlo\AppData\Local\Temp\.arduinoIDE-unsaved2023619-19192-lpqtyx.jlbcl\sketch_jul19a\sketch_jul19a.ino:28:1: error: 'dht' does not name a type
 dht DHT;
 ^~~
C:\Users\Jlo\AppData\Local\Temp\.arduinoIDE-unsaved2023619-19192-lpqtyx.jlbcl\sketch_jul19a\sketch_jul19a.ino: In function 'void loop()':
C:\Users\Jlo\AppData\Local\Temp\.arduinoIDE-unsaved2023619-19192-lpqtyx.jlbcl\sketch_jul19a\sketch_jul19a.ino:64:18: error: expected primary-expression before '.' token
     int chk = DHT.read11(DHT11_PIN);
                  ^
C:\Users\Jlo\AppData\Local\Temp\.arduinoIDE-unsaved2023619-19192-lpqtyx.jlbcl\sketch_jul19a\sketch_jul19a.ino:66:23: error: expected primary-expression before '.' token
     Serial.println(DHT.temperature);
                       ^
C:\Users\Jlo\AppData\Local\Temp\.arduinoIDE-unsaved2023619-19192-lpqtyx.jlbcl\sketch_jul19a\sketch_jul19a.ino:67:15: error: expected primary-expression before '.' token
     temp = DHT.temperature;
               ^
C:\Users\Jlo\AppData\Local\Temp\.arduinoIDE-unsaved2023619-19192-lpqtyx.jlbcl\sketch_jul19a\sketch_jul19a.ino:69:23: error: expected primary-expression before '.' token
     Serial.println(DHT.humidity);
                       ^
C:\Users\Jlo\AppData\Local\Temp\.arduinoIDE-unsaved2023619-19192-lpqtyx.jlbcl\sketch_jul19a\sketch_jul19a.ino:70:14: error: expected primary-expression before '.' token
     hum = DHT.humidity;
              ^
C:\Users\Jlo\AppData\Local\Temp\.arduinoIDE-unsaved2023619-19192-lpqtyx.jlbcl\sketch_jul19a\sketch_jul19a.ino:169:18: error: expected primary-expression before '.' token
     int chk = DHT.read11(DHT11_PIN);
                  ^
C:\Users\Jlo\AppData\Local\Temp\.arduinoIDE-unsaved2023619-19192-lpqtyx.jlbcl\sketch_jul19a\sketch_jul19a.ino:171:23: error: expected primary-expression before '.' token
     Serial.println(DHT.temperature);
                       ^
C:\Users\Jlo\AppData\Local\Temp\.arduinoIDE-unsaved2023619-19192-lpqtyx.jlbcl\sketch_jul19a\sketch_jul19a.ino:172:15: error: expected primary-expression before '.' token
     temp = DHT.temperature;
               ^
C:\Users\Jlo\AppData\Local\Temp\.arduinoIDE-unsaved2023619-19192-lpqtyx.jlbcl\sketch_jul19a\sketch_jul19a.ino:174:23: error: expected primary-expression before '.' token
     Serial.println(DHT.humidity);
                       ^
C:\Users\Jlo\AppData\Local\Temp\.arduinoIDE-unsaved2023619-19192-lpqtyx.jlbcl\sketch_jul19a\sketch_jul19a.ino:175:14: error: expected primary-expression before '.' token
     hum = DHT.humidity;
              ^

exit status 1

Compilation error: 'dht' does not name a type

#include <Servo.h>
#include <DHT.h>
#include <SD.h>
#include <SPI.h>

 #include <Adafruit_Sensor.h>
#define DHT11_PIN 7

#define in1 3  //L298n Motor Driver pins.
#define in2 10
#define in3 4
#define in4 5
#define LED 13
int command;      //Int to store app command state.
int Speed = 204;  // 0 - 255.
int Speedsec;
int buttonState = 0;
int lastButtonState = 0;
int Turnradius = 0;  //Set the radius of a turn, 0 - 255 Note:the robot will malfunction if this is higher than int Speed.
int brakeTime = 45;
int brkonoff = 1;  //1 for the electronic braking system, 0 for normal.

const int TrigPin = 8;
const int EchoPin = 6;
float cm;
float ft;
int temp, hum;
dht DHT;
File sdcard_file;
int CS_pin = 53;
Servo myservo;  // create servo object to control a servo
int pos = 0;    // variable to store the servo position

void setup() {
  Serial.begin(9600);  //Set the baud rate to your Bluetooth module.

  pinMode(in1, OUTPUT);
  pinMode(in2, OUTPUT);
  pinMode(in3, OUTPUT);
  pinMode(in4, OUTPUT);
  pinMode(LED, OUTPUT);  //Set the LED pin.
  pinMode(TrigPin, OUTPUT);
  pinMode(EchoPin, INPUT);
  myservo.attach(9);  // attaches the servo on pin 9 to the servo object
  if (SD.begin()) {
    Serial.println("SD card is ready to use.");
  } else {
    Serial.println("SD card initialization failed");
    return;
  }
  sdcard_file = SD.open("data.txt", FILE_WRITE);
  if (sdcard_file) {
    sdcard_file.print("Temperature ");
    sdcard_file.print("      ");
    sdcard_file.print("Humidity ");
    sdcard_file.println("      ");
    sdcard_file.close();
  } else {
    Serial.println("error opening data.txt");
  }
}
void loop() {
  for (pos = 0; pos <= 180; pos += 1) {  // goes from 0 degrees to 180 degrees
    int chk = DHT.read11(DHT11_PIN);
    Serial.print("Temperature = ");
    Serial.println(DHT.temperature);
    temp = DHT.temperature;
    Serial.print("Humidity = ");
    Serial.println(DHT.humidity);
    hum = DHT.humidity;
    digitalWrite(TrigPin, LOW);
    delayMicroseconds(2);
    digitalWrite(TrigPin, HIGH);
    delayMicroseconds(10);
    digitalWrite(TrigPin, LOW);
    cm = pulseIn(EchoPin, HIGH) / 58.0;  //The echo time is converted into cm
    cm = (int(cm * 100.0)) / 100.0;      //Keep two decimal places
    Serial.print("Distance\t=\t");
    Serial.print(cm);
    Serial.print("cm");
    Serial.println();

    if (Serial.available() > 0) {
      command = Serial.read();
      Stop();  //Initialize with motors stoped.
      switch (command) {
        case 'F':
          forward();
          break;
        case 'B':
          back();
          break;
        case 'L':
          left();
          break;
        case 'R':
          right();
          break;
        case 'G':
          forwardleft();
          break;
        case 'I':
          forwardright();
          break;
        case 'H':
          backleft();
          break;
        case 'J':
          backright();
          break;
        case '0':
          Speed = 100;
          break;
        case '1':
          Speed = 140;
          break;
        case '2':
          Speed = 153;
          break;
        case '3':
          Speed = 165;
          break;
        case '4':
          Speed = 178;
          break;
        case '5':
          Speed = 191;
          break;
        case '6':
          Speed = 204;
          break;
        case '7':
          Speed = 216;
          break;
        case '8':
          Speed = 229;
          break;
        case '9':
          Speed = 242;
          break;
        case 'q':
          Speed = 255;
          break;
      }
      Speedsec = Turnradius;
      if (brkonoff == 1 && cm >= 10) {
        brakeOn();
      } else {
        brakeOff();
      }
    }
    if (cm < 10) {
      Stop();
      sdcard_file = SD.open("data.txt", FILE_WRITE);
      if (sdcard_file) {
        sdcard_file.print(temp);
        sdcard_file.print("     ");
        sdcard_file.print(hum);
        sdcard_file.println("     ");
        sdcard_file.close();
      } else {
        Serial.println("error opening data.txt");
      }
    }
    myservo.write(pos);
    delay(15);
  }
  for (pos = 180; pos >= 0; pos -= 1) {
    int chk = DHT.read11(DHT11_PIN);
    Serial.print("Temperature = ");
    Serial.println(DHT.temperature);
    temp = DHT.temperature;
    Serial.print("Humidity = ");
    Serial.println(DHT.humidity);
    hum = DHT.humidity;
    digitalWrite(TrigPin, LOW);
    delayMicroseconds(2);
    digitalWrite(TrigPin, HIGH);
    delayMicroseconds(10);
    digitalWrite(TrigPin, LOW);
    cm = pulseIn(EchoPin, HIGH) / 58.0;  //The echo time is converted into cm
    cm = (int(cm * 100.0)) / 100.0;      //Keep two decimal places
    Serial.print("Distance\t=\t");
    Serial.print(cm);
    Serial.print("cm");
    Serial.println();

    if (Serial.available() > 0) {
      command = Serial.read();
      Stop();  //Initialize with motors stoped.
      switch (command) {
        case 'F':
          forward();
          break;
        case 'B':
          back();
          break;
        case 'L':
          left();
          break;
        case 'R':
          right();
          break;
        case 'G':
          forwardleft();
          break;
        case 'I':
          forwardright();
          break;
        case 'H':
          backleft();
          break;
        case 'J':
          backright();
          break;
        case '0':
          Speed = 100;
          break;
        case '1':
          Speed = 140;
          break;
        case '2':
          Speed = 153;
          break;
        case '3':
          Speed = 165;
          break;
        case '4':
          Speed = 178;
          break;
        case '5':
          Speed = 191;
          break;
        case '6':
          Speed = 204;
          break;
        case '7':
          Speed = 216;
          break;
        case '8':
          Speed = 229;
          break;
        case '9':
          Speed = 242;
          break;
        case 'q':
          Speed = 255;
          break;
      }
      Speedsec = Turnradius;
      if (brkonoff == 1 && cm >= 10) {
        brakeOn();
      } else {
        brakeOff();
      }
    }
    if (cm < 10) {
      Stop();
      sdcard_file = SD.open("data.txt", FILE_WRITE);
      if (sdcard_file) {
        sdcard_file.print(temp);
        sdcard_file.print("     ");
        sdcard_file.print(hum);
        sdcard_file.println("     ");
        sdcard_file.close();
      } else {
        Serial.println("error opening data.txt");
      }
    }
    if (temp == 27)
      back();

    myservo.write(pos);
    delay(15);
  }
}
void forward() {
  analogWrite(in1, Speed);
  analogWrite(in3, Speed);
}
void back() {
  analogWrite(in2, Speed);
  analogWrite(in4, Speed);
}

void left() {
  analogWrite(in3, Speed);
  analogWrite(in2, Speed);
}
void right() {
  analogWrite(in4, Speed);
  analogWrite(in1, Speed);
}
void forwardleft() {
  analogWrite(in1, Speedsec);
  analogWrite(in3, Speed);
}
void forwardright() {
  analogWrite(in1, Speed);
  analogWrite(in3, Speedsec);
}
void backright() {
  analogWrite(in2, Speed);
  analogWrite(in4, Speedsec);
}
void backleft() {
  analogWrite(in2, Speedsec);
  analogWrite(in4, Speed);
}
void Stop() {
  analogWrite(in1, 0);
  analogWrite(in2, 0);
  analogWrite(in3, 0);
  analogWrite(in4, 0);
}
void brakeOn() {  //Here's the future use: an electronic braking system!
                  // read the pushbutton input pin:
  buttonState = command;
  // compare the buttonState to its previous state
  if (buttonState != lastButtonState) {
    // if the state has changed, increment the counter
    if (buttonState == 'S') {
      if (lastButtonState != buttonState) {
        digitalWrite(in1, HIGH);
        digitalWrite(in2, HIGH);
        digitalWrite(in3, HIGH);
        digitalWrite(in4, HIGH);
        delay(brakeTime);
        Stop();
      }
    }
    lastButtonState = buttonState;
  }
}
void brakeOff() {}`

I combined code and got this error i have download adafruit unified senor and dht library

pylon · July 19, 2023, 2:29pm

All DHT libraries I am aware of (there are a lot of them and you didn't specify which exactly you're using) have a DHT class. I never saw one that defines a dht class. It may be a surprise to you but C++ code is case-sensitive.

larenzia93 · July 19, 2023, 2:35pm

dht sensor library by adafruit

larenzia93 · July 19, 2023, 2:38pm

I changed DHT to dht and now I get this error

C:\Users\Jlo\AppData\Local\Temp\.arduinoIDE-unsaved2023619-19192-lpqtyx.jlbcl\sketch_jul19a\sketch_jul19a.ino:2:10: fatal error: dht.h: No such file or directory
 #include <dht.h>
          ^~~~~~~
compilation terminated.

exit status 1

Compilation error: dht.h: No such file or directory

#include <Servo.h>
#include <dht.h>
#include <SD.h>
#include <SPI.h>



 #include <Adafruit_Sensor.h>
#define DHT11_PIN 7

#define in1 3  //L298n Motor Driver pins.
#define in2 10
#define in3 4
#define in4 5
#define LED 13
int command;      //Int to store app command state.
int Speed = 204;  // 0 - 255.
int Speedsec;
int buttonState = 0;
int lastButtonState = 0;
int Turnradius = 0;  //Set the radius of a turn, 0 - 255 Note:the robot will malfunction if this is higher than int Speed.
int brakeTime = 45;
int brkonoff = 1;  //1 for the electronic braking system, 0 for normal.

const int TrigPin = 8;
const int EchoPin = 6;
float cm;
float ft;
int temp, hum;
dht DHT;
File sdcard_file;
int CS_pin = 53;
Servo myservo;  // create servo object to control a servo
int pos = 0;    // variable to store the servo position

void setup() {
  Serial.begin(9600);  //Set the baud rate to your Bluetooth module.

  pinMode(in1, OUTPUT);
  pinMode(in2, OUTPUT);
  pinMode(in3, OUTPUT);
  pinMode(in4, OUTPUT);
  pinMode(LED, OUTPUT);  //Set the LED pin.
  pinMode(TrigPin, OUTPUT);
  pinMode(EchoPin, INPUT);
  myservo.attach(9);  // attaches the servo on pin 9 to the servo object
  if (SD.begin()) {
    Serial.println("SD card is ready to use.");
  } else {
    Serial.println("SD card initialization failed");
    return;
  }
  sdcard_file = SD.open("data.txt", FILE_WRITE);
  if (sdcard_file) {
    sdcard_file.print("Temperature ");
    sdcard_file.print("      ");
    sdcard_file.print("Humidity ");
    sdcard_file.println("      ");
    sdcard_file.close();
  } else {
    Serial.println("error opening data.txt");
  }
}
void loop() {
  for (pos = 0; pos <= 180; pos += 1) {  // goes from 0 degrees to 180 degrees
    int chk = DHT.read11(DHT11_PIN);
    Serial.print("Temperature = ");
    Serial.println(DHT.temperature);
    temp = DHT.temperature;
    Serial.print("Humidity = ");
    Serial.println(DHT.humidity);
    hum = DHT.humidity;
    digitalWrite(TrigPin, LOW);
    delayMicroseconds(2);
    digitalWrite(TrigPin, HIGH);
    delayMicroseconds(10);
    digitalWrite(TrigPin, LOW);
    cm = pulseIn(EchoPin, HIGH) / 58.0;  //The echo time is converted into cm
    cm = (int(cm * 100.0)) / 100.0;      //Keep two decimal places
    Serial.print("Distance\t=\t");
    Serial.print(cm);
    Serial.print("cm");
    Serial.println();

    if (Serial.available() > 0) {
      command = Serial.read();
      Stop();  //Initialize with motors stoped.
      switch (command) {
        case 'F':
          forward();
          break;
        case 'B':
          back();
          break;
        case 'L':
          left();
          break;
        case 'R':
          right();
          break;
        case 'G':
          forwardleft();
          break;
        case 'I':
          forwardright();
          break;
        case 'H':
          backleft();
          break;
        case 'J':
          backright();
          break;
        case '0':
          Speed = 100;
          break;
        case '1':
          Speed = 140;
          break;
        case '2':
          Speed = 153;
          break;
        case '3':
          Speed = 165;
          break;
        case '4':
          Speed = 178;
          break;
        case '5':
          Speed = 191;
          break;
        case '6':
          Speed = 204;
          break;
        case '7':
          Speed = 216;
          break;
        case '8':
          Speed = 229;
          break;
        case '9':
          Speed = 242;
          break;
        case 'q':
          Speed = 255;
          break;
      }
      Speedsec = Turnradius;
      if (brkonoff == 1 && cm >= 10) {
        brakeOn();
      } else {
        brakeOff();
      }
    }
    if (cm < 10) {
      Stop();
      sdcard_file = SD.open("data.txt", FILE_WRITE);
      if (sdcard_file) {
        sdcard_file.print(temp);
        sdcard_file.print("     ");
        sdcard_file.print(hum);
        sdcard_file.println("     ");
        sdcard_file.close();
      } else {
        Serial.println("error opening data.txt");
      }
    }
    myservo.write(pos);
    delay(15);
  }
  for (pos = 180; pos >= 0; pos -= 1) {
    int chk = DHT.read11(DHT11_PIN);
    Serial.print("Temperature = ");
    Serial.println(DHT.temperature);
    temp = DHT.temperature;
    Serial.print("Humidity = ");
    Serial.println(DHT.humidity);
    hum = DHT.humidity;
    digitalWrite(TrigPin, LOW);
    delayMicroseconds(2);
    digitalWrite(TrigPin, HIGH);
    delayMicroseconds(10);
    digitalWrite(TrigPin, LOW);
    cm = pulseIn(EchoPin, HIGH) / 58.0;  //The echo time is converted into cm
    cm = (int(cm * 100.0)) / 100.0;      //Keep two decimal places
    Serial.print("Distance\t=\t");
    Serial.print(cm);
    Serial.print("cm");
    Serial.println();

    if (Serial.available() > 0) {
      command = Serial.read();
      Stop();  //Initialize with motors stoped.
      switch (command) {
        case 'F':
          forward();
          break;
        case 'B':
          back();
          break;
        case 'L':
          left();
          break;
        case 'R':
          right();
          break;
        case 'G':
          forwardleft();
          break;
        case 'I':
          forwardright();
          break;
        case 'H':
          backleft();
          break;
        case 'J':
          backright();
          break;
        case '0':
          Speed = 100;
          break;
        case '1':
          Speed = 140;
          break;
        case '2':
          Speed = 153;
          break;
        case '3':
          Speed = 165;
          break;
        case '4':
          Speed = 178;
          break;
        case '5':
          Speed = 191;
          break;
        case '6':
          Speed = 204;
          break;
        case '7':
          Speed = 216;
          break;
        case '8':
          Speed = 229;
          break;
        case '9':
          Speed = 242;
          break;
        case 'q':
          Speed = 255;
          break;
      }
      Speedsec = Turnradius;
      if (brkonoff == 1 && cm >= 10) {
        brakeOn();
      } else {
        brakeOff();
      }
    }
    if (cm < 10) {
      Stop();
      sdcard_file = SD.open("data.txt", FILE_WRITE);
      if (sdcard_file) {
        sdcard_file.print(temp);
        sdcard_file.print("     ");
        sdcard_file.print(hum);
        sdcard_file.println("     ");
        sdcard_file.close();
      } else {
        Serial.println("error opening data.txt");
      }
    }
    if (temp == 27)
      back();

    myservo.write(pos);
    delay(15);
  }
}
void forward() {
  analogWrite(in1, Speed);
  analogWrite(in3, Speed);
}
void back() {
  analogWrite(in2, Speed);
  analogWrite(in4, Speed);
}

void left() {
  analogWrite(in3, Speed);
  analogWrite(in2, Speed);
}
void right() {
  analogWrite(in4, Speed);
  analogWrite(in1, Speed);
}
void forwardleft() {
  analogWrite(in1, Speedsec);
  analogWrite(in3, Speed);
}
void forwardright() {
  analogWrite(in1, Speed);
  analogWrite(in3, Speedsec);
}
void backright() {
  analogWrite(in2, Speed);
  analogWrite(in4, Speedsec);
}
void backleft() {
  analogWrite(in2, Speedsec);
  analogWrite(in4, Speed);
}
void Stop() {
  analogWrite(in1, 0);
  analogWrite(in2, 0);
  analogWrite(in3, 0);
  analogWrite(in4, 0);
}
void brakeOn() {  //Here's the future use: an electronic braking system!
                  // read the pushbutton input pin:
  buttonState = command;
  // compare the buttonState to its previous state
  if (buttonState != lastButtonState) {
    // if the state has changed, increment the counter
    if (buttonState == 'S') {
      if (lastButtonState != buttonState) {
        digitalWrite(in1, HIGH);
        digitalWrite(in2, HIGH);
        digitalWrite(in3, HIGH);
        digitalWrite(in4, HIGH);
        delay(brakeTime);
        Stop();
      }
    }
    lastButtonState = buttonState;
  }
}
void brakeOff() {}

larenzia93 · July 19, 2023, 2:53pm

C:\Users\Jlo\Documents\Arduino\libraries yes i have the file

larenzia93 · July 19, 2023, 2:55pm

no its not

larenzia93 · July 19, 2023, 2:56pm

its in a folder called dht_sensor_library

oqibidipo · July 19, 2023, 3:02pm

I think you need this library instead:

larenzia93 · July 19, 2023, 3:15pm

what include statement do i use if i upload this library

oqibidipo · July 19, 2023, 3:20pm

#include <dht.h>

pylon · July 21, 2023, 4:28pm

I think the include file is still called DHT.h.

oqibidipo · July 21, 2023, 5:40pm

I know it is lowercase.

https://github.com/RobTillaart/DHTlib/blob/master/dht.h

pylon · July 21, 2023, 6:35pm

But that library calls the class "dht". You should follow the examples of the library you're using!

oqibidipo · July 21, 2023, 6:43pm

The code in the OP uses dht class.
The code compiles after changing the #include to <dht.h>.

system · January 17, 2024, 6:43pm

This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.

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I am getting a error (dht does not name a type)

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