Naive Decimal to Hex Converter using Arduino

Instruction:

1. User types decimal number (0-15) in serial monitor.
2. Arduino reads the input and shows the corresponding hexadecimal number using Single seven segment display.
3. If user types a out of range decimal value, Arduino will handle that by flashing “E” on the seven-segment display and an error message in serial monitor.

Design:

Code:

/*
Name: Naive Decimal to Hex Converter
*/
int pin_2 = 2;
int pin_3 = 3;
int pin_4 = 4;
int pin_5 = 5;
int pin_6 = 6;
int pin_7 = 7;
int pin_8 = 8;
String string = "";       //initialize string  

void displayZero() {
   digitalWrite(pin_2, HIGH);
   digitalWrite(pin_3, HIGH);
   digitalWrite(pin_4, HIGH);
   digitalWrite(pin_5, HIGH);
   digitalWrite(pin_6, HIGH);
   digitalWrite(pin_7, HIGH);
   digitalWrite(pin_8, LOW);
}

void displayOne() {
   digitalWrite(pin_2, LOW);
   digitalWrite(pin_3, HIGH);
   digitalWrite(pin_4, HIGH);
   digitalWrite(pin_5, LOW);
   digitalWrite(pin_6, LOW);
   digitalWrite(pin_7, LOW);
   digitalWrite(pin_8, LOW);
}

void displayTwo() {
   digitalWrite(pin_2, HIGH);
   digitalWrite(pin_3, HIGH);
   digitalWrite(pin_4, LOW);
   digitalWrite(pin_5, HIGH);
   digitalWrite(pin_6, HIGH);
   digitalWrite(pin_7, LOW);
   digitalWrite(pin_8, HIGH);
}

void displayThree() {
   digitalWrite(pin_2, HIGH);
   digitalWrite(pin_3, HIGH);
   digitalWrite(pin_4, HIGH);
   digitalWrite(pin_5, HIGH);
   digitalWrite(pin_6, LOW);
   digitalWrite(pin_7, LOW);
   digitalWrite(pin_8, HIGH);  
}

void displayFour() {
   digitalWrite(pin_2, LOW);
   digitalWrite(pin_3, HIGH);
   digitalWrite(pin_4, HIGH);
   digitalWrite(pin_5, LOW);
   digitalWrite(pin_6, LOW);
   digitalWrite(pin_7, HIGH);
   digitalWrite(pin_8, HIGH);
}

void displayFive() {
   digitalWrite(pin_2, HIGH);
   digitalWrite(pin_3, LOW);
   digitalWrite(pin_4, HIGH);
   digitalWrite(pin_5, HIGH);
   digitalWrite(pin_6, LOW);
   digitalWrite(pin_7, HIGH);
   digitalWrite(pin_8, HIGH);
}

void displaySix() {
   digitalWrite(pin_2, HIGH);
   digitalWrite(pin_3, LOW);
   digitalWrite(pin_4, HIGH);
   digitalWrite(pin_5, HIGH);
   digitalWrite(pin_6, HIGH);
   digitalWrite(pin_7, HIGH);
   digitalWrite(pin_8, HIGH);
}

void displaySeven() {
   digitalWrite(pin_2, HIGH);
   digitalWrite(pin_3, HIGH);
   digitalWrite(pin_4, HIGH);
   digitalWrite(pin_5, LOW);
   digitalWrite(pin_6, LOW);
   digitalWrite(pin_7, LOW);
   digitalWrite(pin_8, LOW);
}

void displayEight() {
   digitalWrite(pin_2, HIGH);
   digitalWrite(pin_3, HIGH);
   digitalWrite(pin_4, HIGH);
   digitalWrite(pin_5, HIGH);
   digitalWrite(pin_6, HIGH);
   digitalWrite(pin_7, HIGH);
   digitalWrite(pin_8, HIGH);
}

void displayNine() {
   digitalWrite(pin_2, HIGH);
   digitalWrite(pin_3, HIGH);
   digitalWrite(pin_4, HIGH);
   digitalWrite(pin_5, LOW);
   digitalWrite(pin_6, LOW);
   digitalWrite(pin_7, HIGH);
   digitalWrite(pin_8, HIGH);
}

void displayA() {
   digitalWrite(pin_2, HIGH);
   digitalWrite(pin_3, HIGH);
   digitalWrite(pin_4, HIGH);
   digitalWrite(pin_5, LOW);
   digitalWrite(pin_6, HIGH);
   digitalWrite(pin_7, HIGH);
   digitalWrite(pin_8, HIGH);
}

void displayB() {
   digitalWrite(pin_2, LOW);
   digitalWrite(pin_3, LOW);
   digitalWrite(pin_4, HIGH);
   digitalWrite(pin_5, HIGH);
   digitalWrite(pin_6, HIGH);
   digitalWrite(pin_7, HIGH);
   digitalWrite(pin_8, HIGH);
}

void displayC() {
   digitalWrite(pin_2, HIGH);
   digitalWrite(pin_3, LOW);
   digitalWrite(pin_4, LOW);
   digitalWrite(pin_5, HIGH);
   digitalWrite(pin_6, HIGH);
   digitalWrite(pin_7, HIGH);
   digitalWrite(pin_8, LOW);
}

void displayD() {
   digitalWrite(pin_2, LOW);
   digitalWrite(pin_3, HIGH);
   digitalWrite(pin_4, HIGH);
   digitalWrite(pin_5, HIGH);
   digitalWrite(pin_6, HIGH);
   digitalWrite(pin_7, LOW);
   digitalWrite(pin_8, HIGH);
}

void displayE() {
   digitalWrite(pin_2, HIGH);
   digitalWrite(pin_3, LOW);
   digitalWrite(pin_4, LOW);
   digitalWrite(pin_5, HIGH);
   digitalWrite(pin_6, HIGH);
   digitalWrite(pin_7, HIGH);
   digitalWrite(pin_8, HIGH);
}

void displayF() {
   digitalWrite(pin_2, HIGH);
   digitalWrite(pin_3, LOW);
   digitalWrite(pin_4, LOW);
   digitalWrite(pin_5, LOW);
   digitalWrite(pin_6, HIGH);
   digitalWrite(pin_7, HIGH);
   digitalWrite(pin_8, HIGH);
}

void setup() {    
  //set pin 2 to 8 as output  
  pinMode(pin_2, OUTPUT); 
  pinMode(pin_3, OUTPUT);
  pinMode(pin_4, OUTPUT);
  pinMode(pin_5, OUTPUT);
  pinMode(pin_6, OUTPUT);
  pinMode(pin_7, OUTPUT);
  pinMode(pin_8, OUTPUT);
  Serial.begin(9600); //initialize serial
}

void loop() {
    if(Serial.available() > 0){
        char ch = (char) Serial.read();
        if(ch == '\r') {
            if(string == "0") {
               displayZero(); 
            } else if(string == "1") {
               displayOne(); 
            } else if(string == "2") {
               displayTwo(); 
            } else if(string == "3") {
               displayThree(); 
            } else if(string == "4") {
               displayFour(); 
            } else if(string == "5") {
               displayFive(); 
            } else if(string == "6") {
               displaySix(); 
            } else if(string == "7") {
               displaySeven(); 
            } else if(string == "8") {
               displayEight(); 
            } else if(string == "9") {
               displayNine(); 
            } else if(string == "10") {
               displayA(); 
            } else if(string == "11") {
               displayB(); 
            } else if(string == "12") {
               displayC(); 
            } else if(string == "13") {
               displayD(); 
            } else if(string == "14") {
               displayE(); 
            } else if(string == "15") {
               displayF(); 
            } else {
               displayE();
               Serial.println("NUMBER IS OUT OF RANGE");
            }
            string = ""; 
        } else {
            string += ch; 
        }
    }
}