Error Messages when trying to use DHT22 Sensor

Projects Programming
1

I'm attempting to build a thermostat that uses a DHT22 temperature and humidity sensor to determine the temperature and relative humidity in the room. I have a prototype, however whenever I try to verify the code, I get an error message. the line of code originally read "dht DHT" I added an int in front of it and it said "Thermostat:13: error: expected initializer before 'DHT' " As I am very new to using arduino, I don't what that means and I'm not even sure if int is the right thing to write in this case. Thanks

2

Did you include the header file?

#include <dht.h> // or whatever the header file is called
3

If you had posted your code SurferTim wouldn't have had to guess.

4

The library takes care of dht so why would you add a int in front of it. Now you have made a new int called dht that will only be seen in the program and "int dht DHT" is not a valid command

My library may be different but

DHT dht(DHTPIN, DHTTYPE);

is the normal command line that says call DHT library. Make a name dht and assign pin and type data

in the loop if you want to assign a int or float then you should use code like

 // Read temperature as Celsius
  float t = dht.readTemperature();

Once you post your code we can help you further

5

#include <DHT22.h>

dht DHT;
#include <LiquidCrystal.h>
//#define DHT11_PIN 4
//#define DHT21_PIN 5
#define DHT22_PIN 6

//pinMode(0,INPUT);
//pinMode(1,OUTPUT);
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);
void setup()
{
Serial.begin(9600);
Serial.println("DHT TEST PROGRAM ");
Serial.print("LIBRARY VERSION: ");
//Serial.println(DHT_LIB_VERSION);
Serial.println();
Serial.println("Type,\tstatus,\tHumidity (%),\tTemperature (C)");
lcd.begin(20, 4);
lcd.print("Heat Index");

}

void loop()
{
// READ DATA
Serial.print("DHT22, \t");
int chk = DHT.read22(DHT22_PIN);
switch (chk)
{
case DHTLIB_OK:
Serial.print("OK,\t");
break;
case DHTLIB_ERROR_CHECKSUM:
Serial.print("Checksum error,\t");
break;
case DHTLIB_ERROR_TIMEOUT:
Serial.print("Time out error,\t");
break;
default:
Serial.print("Unknown error,\t");
break;
}
int T=DHT.temperature //Defines the tempurature reading
int R=DHT.humidity //defines the humidity reading
int H=0 //Defines variable H which will later be used to represent Heat Index
Serial.print(T);
Serial.print(R);
#if 0
//;Serial.print(-42.379 + 2.04901523T + 10.14333127R - 0.22475541TR - 6.83783 * 10-3TT - 5.481717 * 10-2RR + 1.22874 * 10-3TTR * 8.5282 * 10-4TRR - 1.99 * 10-6TTRR=H);
if(H<68);
digitalWrite(1,HIGH);
if(H>=72);
digitalWrite(1,LOW):wink:
#endif
// set the cursor to column 0, line 1
// (note: line 1 is the second row, since counting begins with 0):
lcd.setCursor(0, 1);
// print the number of seconds since reset:
lcd.print(H);
}

6 
if(H<68);

if statements rarely end with semicolons.