Code:-

Step 3: Code:-

#include "LedControl.h" // need the library
LedControl lc=LedControl(2,1,0,1); // lc is our object
// pin 2 is connected to the MAX7219 pin 1
// pin 1 is connected to the CLK pin 13
// pin 0 is connected to LOAD pin 12
// 1 as we are only using 1 MAX7219
int buttonState=0;         // current state of the button
int lastButtonState=0;     // previous state of the button
const int buttonPin=4;
int tempPin=3;
float sample;
float tempC;
float tempF;
void setup()
{
pinMode(buttonPin,INPUT);
pinMode(tempPin,INPUT);
lc.shutdown(0,false);// turn off power saving, enables display
lc.setIntensity(0,15);// sets brightness (0~15 possible values)
lc.clearDisplay(0);// clear screen
}
void printNumber(float num)
{
int ones;
int tens;
int hundreds;
int v=(int)num;
float diff=num-v;
diff=diff*100;
int fones,ftens;
fones=(int)diff%10;
diff=diff/10;
ftens=(int)diff%10;
diff=diff/10;
ones=v%10;
v=v/10;
tens=v%10;
v=v/10;
hundreds=v;
//Now print the number digit by digit
lc.setDigit(0,4,(byte)hundreds,false);
lc.setDigit(0,3,(byte)tens,false);
lc.setDigit(0,2,(byte)ones,true);
lc.setDigit(0,1,(byte)ftens,false);
lc.setDigit(0,0,(byte)fones,false);
}
void loop()
{
buttonState=digitalRead(buttonPin);
sample=0;
for(int i=0;i<150;i++)
{
    sample+=analogRead(tempPin); //read the value from the sensor
    delay(2);
}
sample=sample/150;
tempC=(5.0*sample*100.0)/1023.0;   //convert the analog data to temperature
if(buttonState!=lastButtonState)
{
     lastButtonState=buttonState;
}
if(lastButtonState==1)
    {
      printNumber(tempC);
      delay(200);
    }
    if(lastButtonState==0)
    {
      tempF=((tempC*9)/5)+32;
      printNumber(tempF);
      delay(200);
    }
}