DATA ACQUISTION SYSTEM

Basic blocks of a "Data Acquistion System"   

 

                                                                       

•  This is a simple system that convert two physical quantities (Temperate & light intensity) into Digital quantities.
• For temp i used LM35 sensor which convert the physical signal into voltage(in mV).
• To make it compatible with micro controller (PIC18f452) , i used op amp 741 to boost the voltage from 10mV to 5V , this is nothing but "Signal Conditioning".
• same with light,where i used  LDR as sensor.

 CODE

• #include<p18f452.h>
  
  //FOR WATCHDOG TIMER
  
  #pragma config WDT=OFF
  #pragma config OSC=HS,OSCS=OFF                      
  #pragma config BORV=45,PWRT=ON,BOR=ON
  
  #define rs PORTCbits.RC5
  #define rw PORTCbits.RC6
  #define en PORTCbits.RC7
  #define sdata PORTD
  
  
  void lcdcmd(unsigned char);
  void lcddata(unsigned char);
  void adc_con(int);
  void adc_con1(int);
  void adc_init(void);
  void Print_string(char *A);
  void Delay_ms(int);
  
   char data[6]="TEMP";
  char data1[3]="|";
  char data2[6]="LUX";
  float TEMPRATURE[10],avg_output=0,temp;
  float LDR[10],avg_output1=0,temp1;
  unsigned int i=0;
  
  
  
  
  
  void main(void)
  {
      TRISA=0x0f;        // Configure RA0 as input pin
     
      TRISB=0;        // Configure Port B as output port
     
      TRISC=0;
    
      TRISD=0;
     
      lcdcmd(0x38);        // Configure the LCD in 8-bit mode, 2 line and 5x7 font
      lcdcmd(0x0C);        // Display On and Cursor Off
      lcdcmd(0x01);        // Clear display screen
      lcdcmd(0x06);        // Increment cursor
      lcdcmd(0x80);        // Set cursor position to 1st line, 1st column
  
  
      Print_string(data);
   lcdcmd(0x87); 
        Print_string(data1);
  lcdcmd(0xC7); 
        Print_string(data1);
   lcdcmd(0x8C); 
        Print_string(data2);
  
      adc_init();        //ADC Initialization
  
      while(1)
      {
        
              ADCON0=0x81;
              temp=0;
              for(i=0;i<10;i++)
              {
                
                  ADCON0bits.GO=1;                     // Start A/D
                  while(ADCON0bits.DONE==1);             // Wait
             
                  TEMPRATURE[i]=ADRES ;                     //Store data
                  Delay_ms(5);
                  temp=temp+TEMPRATURE[i];
  
              }
              avg_output=temp/10;
              avg_output=(avg_output/1024)*150;                  // Take average
              adc_con(avg_output);                     // decimal to ASCII
  
  
  
              ADRES=0;
      ADCON0=0x89;
                  temp1=0;
              for(i=0;i<10;i++)
              {
                    
                  ADCON0bits.GO=1;                     // Start A/D
                  while(ADCON0bits.DONE==1);             // Wait
             
                  LDR[i]=ADRES ;                     //Store data
                  Delay_ms(5);
                  temp1=temp1+LDR[i];
  
              }
              avg_output1=temp1/10;
              avg_output1=(1024-avg_output1);                  // Take average
              adc_con1(avg_output1);                     // decimal to ASCII
  
  
  
  
  
  
  }
  }
  
  
  void Print_string(char *a)
  {
   int i;
   for(i=0;(*(a+i))!='\0';i++)
     {
       lcddata(*(a+i));
     }
  }
  
  
  void adc_init()
  {
      ADCON1=0xC5;                          // Make RA0/AN0 ,RA1,RA2 ANALOG
                                 // Select Channel0 & ADC off
  //     ADCON2=0x85;                            //  Fosc/32 clock option
      ADCON0=0x81;                          // Enable ADC
  }
  
     
  
  
  
  
  void adc_con( int adc_out)
  {
      int adc_out1;
      int i=0;
      char position=0xC3;
  
  
      for(i=0;i<=3;i++)
      {
          adc_out1=adc_out%10;                     // To exract the unit position digit
          adc_out=adc_out/10;
          lcdcmd(position);
          lcddata(48+adc_out1);                    // Convert into its corresponding ASCII
          position--;
  
      }
  }
  
  void adc_con1( int adc)
  {
      int adc_out2;
      int i=0;
      char position=0xCF;
  
  
      for(i=0;i<=3;i++)
      {
          adc_out2=adc%10;                     // To exract the unit position digit
          adc=adc/10;
          lcdcmd(position);
          lcddata(48+adc_out2);                    // Convert into its corresponding ASCII
          position--;
  
      }
  }
  
  
  void lcdcmd(unsigned char cmdout)
  {
      sdata=cmdout;        //Send command to lcdport=PORTB
      rs=0;                       
      rw=0;
      en=1;
      Delay_ms(20);
      en=0;
  }
  
  
  void lcddata(unsigned char dataout)
  {
     
      sdata=dataout;    //Send data to lcdport=PORTB
      rs=1;
      rw=0;
      en=1;
      Delay_ms(30);
      en=0;
  }
  
  
  void Delay_ms(int d)
  {
  int i,j;
  for(i=0;i<d;i++)
  {
      for(j=0;j<d;j++)
      {
      }
  }
  }