#define dht_dpin A0



byte bGlobalErr;



byte dht_dat[5];



 



void setup(){



InitDHT();



Serial.begin(9600);



delay(300);



Serial.println("Humidity and temperaturenn");



delay(700);



}



 



void loop(){



  ReadDHT();



  switch (bGlobalErr){



     case 0:



 Serial.print("Current humdity = ");



 Serial.print(dht_dat[0], DEC);



 Serial.print(".");



 Serial.print(dht_dat[1], DEC);



 Serial.print("%  ");



 Serial.print("temperature = ");



 Serial.print(dht_dat[2], DEC);



 Serial.print(".");



 Serial.print(dht_dat[3], DEC);



 Serial.println("C  ");



        break;



     case 1:



        Serial.println("Error 1: DHT start condition 1 not met.");



        break;



     case 2:



        Serial.println("Error 2: DHT start condition 2 not met.");



        break;



     case 3:



        Serial.println("Error 3: DHT checksum error.");



        break;



     default:



        Serial.println("Error: Unrecognized code encountered.");



        break;



      }



  delay(800);



}



 



void InitDHT(){



   pinMode(dht_dpin,OUTPUT);



        digitalWrite(dht_dpin,HIGH);



}



 



void ReadDHT(){



bGlobalErr=0;



byte dht_in;



byte i;



digitalWrite(dht_dpin,LOW);



delay(20);



 



digitalWrite(dht_dpin,HIGH);



delayMicroseconds(40);



pinMode(dht_dpin,INPUT);



//delayMicroseconds(40);



dht_in=digitalRead(dht_dpin);



 



if(dht_in){



   bGlobalErr=1;



   return;



   }



delayMicroseconds(80);



dht_in=digitalRead(dht_dpin);



 



if(!dht_in){



   bGlobalErr=2;



   return;



   }



delayMicroseconds(80);



for (i=0; i<5; i++)



   dht_dat[i] = read_dht_dat();



pinMode(dht_dpin,OUTPUT);



digitalWrite(dht_dpin,HIGH);



byte dht_check_sum =



       dht_dat[0]+dht_dat[1]+dht_dat[2]+dht_dat[3];



if(dht_dat[4]!= dht_check_sum)



   {bGlobalErr=3;}



};



 



byte read_dht_dat(){



  byte i = 0;



  byte result=0;



  for(i=0; i< 8; i++){



      while(digitalRead(dht_dpin)==LOW);



      delayMicroseconds(30);



      if (digitalRead(dht_dpin)==HIGH)



     result |=(1<<(7-i));



    while (digitalRead(dht_dpin)==HIGH);



    }



  return result;



}