Electronics: Powerful stuff

				
					console.log( Pin connections
  
  P0 = 
  P1 = Relay 1 (HIGH = ON)
  P2 = 
  P3 = 
  P4 =
  P5 = DS18B20
  
    DS18B20 Pinout (Left to Right, pins down, flat side toward you)
    - Left   = Ground
    - Center = Signal (Pin 2):  (with 3.3K to 4.7K resistor to +5 or 3.3 )
    - Right  = +5 or +3.3 V
  
     DS18B20 Temperature chip on pin P5
     4k7 pullup between pin P5 and +5v.
     
     Created 19 Apr 2017
     by Mark Beckett

     based on the code here http://forum.arduino.cc/index.php?topic=72654.msg546490#msg546490
   
     */
     
  #include <OneWire.h>
  // Use P2 to avoid issues with clones 
  #define DS18B20_PIN 2                   // DS18B20 is on P2 (Clone Digisparks being sold have P5 as the reset as they have the wrong fuse settings)
  
  // DS18B20 Temperature chip i/o
  OneWire ds(DS18B20_PIN);                 // TempSensor

  // maximum sensors on the bus
  #define M 5

  // actual sensors detected
  byte m = 0 ;

  // addresses
  byte addr[M][8];

  //Outputs
  const int Relay1 = 1;               // Relay 1 Output

  //Settings
  int Highest = 0;                     // Highest of all sensors.
  int HighTempOn = 45;                 // High Temperature On setting
  int HighTempOff = 30;                // High Temperature Off setting

  //-------------------------------------------------------------------------

  void setup_tempsense ()
  {
   m = 0 ;
   while (ds.search (addr[m]))
   {
      if (OneWire::crc8 (addr[m], 7) != addr[m][7])
      {
        return ;
      }
      if (addr[m][0] != 0x28)
      {
        return ;
      }
      m++ ;
    }
    ds.reset_search () ;
  }

  // asynchrounous start conversion
  int start_conversion (byte i)
  {

    ds.reset () ;
    ds.select (addr[i]) ;
    ds.write (0x44) ;         // start conversion, with parasite power on at the end
  }

  // asynchrounous read result
  int read_conversion_result (byte i)
  {
    byte present = ds.reset () ;
    ds.select (addr[i]) ;   
    ds.write (0xBE) ;         // Read Scratchpad

    byte data[9];
    for (byte i = 0 ; i < 9 ; i++)           // we need 9 bytes
    {
      data[i] = ds.read();
    }
    int temp = (data [1] << 8) | data[0] ;   // just want temperature
    return temp ;
  }


  // synchronous call to read temperature from one sensor
  int read_temp (byte i)
  {
    start_conversion (i) ;
    delay (800) ;     // maybe 750ms is enough, maybe not
    return read_conversion_result (i) ;
  }


  void setup ()
  {
    //Define the pins
    pinMode(Relay1, OUTPUT);
    digitalWrite (Relay1, LOW);    //Relay is OFF 
    delay (500) ;
  
    setup_tempsense () ;

  }

  void loop ()
  {
    // start all the conversions
    for (byte i = 0 ; i < m ; i++)
    {
      start_conversion (i) ;
    }
    // share the wait
    delay (750) ;
    // read all the results
    for (byte i = 0 ; i < m ; i++)
    {
      //Serial.print ("dev ") ;
      //show_id (i) ;
      int temp = read_conversion_result (i) ;
      float centigrade = ((float) temp) * 0.0625 ;
   
      if(centigrade > Highest)
      {
        Highest = centigrade;
      }
    
    }

    RelayControl();
    Highest = 0;            //reset the reading at each trip thru the sensors.
    delay (250) ;
  }
 
  void RelayControl() 
  {
       //Relays are ON when the output pin is HIGH

       if (Highest >= HighTempOn)                              //reading is above or equal to the setting
       {
         digitalWrite(Relay1,HIGH);
       }
       
       if (Highest <= HighTempOff)                              //reading is below or equal to the setting
       {
         digitalWrite(Relay1,LOW);
       }

  }
  );