//PIC16F877A DHT11 digital humidity and
 //       temperature sensor MikroC code
//Written by: ABDALLA HYGSZY //
//Crystal used : 12MHz
//Use at your own risk


// LCD module connections
 sbit LCD_RS at RB0_bit;
 sbit LCD_EN at RB1_bit;
 sbit LCD_D4 at RB2_bit;
 sbit LCD_D5 at RB3_bit;
 sbit LCD_D6 at RB4_bit;
 sbit LCD_D7 at RB5_bit;
 sbit LCD_RS_Direction at TRISB0_bit;
 sbit LCD_EN_Direction at TRISB1_bit;
 sbit LCD_D4_Direction at TRISB2_bit;
 sbit LCD_D5_Direction at TRISB3_bit;
 sbit LCD_D6_Direction at TRISB4_bit;
 sbit LCD_D7_Direction at TRISB5_bit;
 // End LCD module connections
 unsigned char  Check, T_byte1, T_byte2,
                RH_byte1, RH_byte2, Ch ;
 unsigned Temp, RH, Sum ;
void StartSignal(){
 TRISD.F0 = 0;    //Configure RD0 as output
 PORTD.F0 = 0;    //RD0 sends 0 to the sensor
 delay_ms(18);
 PORTD.F0 = 1;    //RD0 sends 1 to the sensor
 delay_us(30);
 TRISD.F0 = 1;    //Configure RD0 as input
  }
 //////////////////////////////
 void CheckResponse(){
 Check = 0;
 delay_us(40);
 if (PORTD.F0 == 0){
 delay_us(80);
 if (PORTD.F0 == 1)   Check = 1;   delay_us(40);}
 }
 //////////////////////////////
 char ReadData(){
 char i, j;
 for(j = 0; j < 8; j++){
 while(!PORTD.F0); //Wait until PORTD.F0 goes HIGH
 delay_us(30);
 if(PORTD.F0 == 0)
       i&= ~(1<<(7 - j));  //Clear bit (7-b)
 else {i|= (1 << (7 - j));  //Set bit (7-b)
 while(PORTD.F0);}  //Wait until PORTD.F0 goes LOW
 }
 return i;
 }
 //////////////////////////////
void main() {
 TRISD.F1 = 0;
 Lcd_Init();
 Lcd_Cmd(_LCD_CURSOR_OFF);        // cursor off
 Lcd_Cmd(_LCD_CLEAR);            // clear LCD
 while(1){
 
 StartSignal();
  CheckResponse();
  if(Check == 1){
  RH_byte1 = ReadData();
  RH_byte2 = ReadData();
  T_byte1 = ReadData();
  T_byte2 = ReadData();
  Sum = ReadData();
  if(Sum == ((RH_byte1+RH_byte2+T_byte1+T_byte2) & 0XFF)){
    Lcd_Cmd(_LCD_CLEAR);
  Temp = T_byte1;
  RH = RH_byte1;
  Lcd_Out(1, 6, "Temp:   C");
  Lcd_Out(2, 2, "Humidity:   %");
  LCD_Chr(1, 12, 48 + ((Temp / 10) % 10));
  LCD_Chr(1, 13, 48 + (Temp % 10));
  LCD_Chr(2, 12, 48 + ((RH / 10) % 10));
  LCD_Chr(2, 13, 48 + (RH % 10));
  
  
  }
  else{   Lcd_Cmd(_LCD_CLEAR);
  Lcd_Cmd(_LCD_CURSOR_OFF);        // cursor off
  Lcd_Cmd(_LCD_CLEAR);             // clear LCD
  Lcd_Out(1, 1, "Check sum error");}
  }
  else {
  
  
  //Lcd_Out(1, 3, "No response");
 // Lcd_Out(2, 1, "from the sensor");
 
  }
  delay_ms(1000);
  }
}