Q.No.4 - Write a program for interfacing temperature sensor and set condition when temperature above 110 degree celsius three led On, 70-110 degree celsius two led On and last 40-70 one led on.

Sol.- 

void setup()
{
  pinMode(A0,INPUT);
  pinMode(2,OUTPUT);
  pinMode(4,OUTPUT);
  pinMode(7,OUTPUT);
  Serial.begin(9600);
}
void loop()
{
  int ra=analogRead(A0);
  float mil=(ra/1024.0)*5000;
  float celsius=mil/10-49;
  Serial.print("Temperature Reading:");
  Serial.println(celsius);
  if(celsius>110)
  { digitalWrite(2,1);
    digitalWrite(4,1);
    digitalWrite(7,1);}
  else if(celsius>70)
  		{digitalWrite(2,1);
        digitalWrite(4,1);
  		 digitalWrite(7,0);}
  else if(celsius>40)
  	{digitalWrite(2,1);
   	 digitalWrite(4,0);
  	 digitalWrite(7,0);}
  else
  {digitalWrite(2,0);
   digitalWrite(4,0);
   digitalWrite(7,0);
  }   
}




Requirement - Arduino, Jumper wire, resistor (220 ohm), 3 Led, One temperature sensor, Breadoard.

OUTPUT: