Final Project

• Computer - Aided Design
• Molding and Casting
• Mechanical Design

 I begin my code by defining the pins I’m going to use.

                    
                      
  #define op1 11
  #define op0 A2
  #define x3 A5
  #define x2 A4
  #define x1 A3
  #define x0 A1
  #define y3 4
  #define y2 3
  #define y1 2
  #define y0 A0
  #define sw1 0
  #define sw2 1
 
     
                         

and then define which pins are going to be used for the LCD display.

                    
                      
// include the library code:

#include <LiquidCrystal.h>
const int rs = 5, en = 6, d4 = 7, d5 = 8, d6 = 9, d7 = 10;
LiquidCrystal lcd(rs, en, d4, d5, d6, d7);

// initialize the library with the numbers of the interface pins 
 
     
                         

Then, I Initialize my variables:

                    
                      
  char operation_sym[4] = { '+', '-', '*', '/' }; 
  int n1 =0;
  int n2 =0;
  int operation=0;
  int ans, r_ans;
 
     
                         

and in the Void Setup, I define the pin modes for the pins I’m going to use, and initialize my LCD .

                    
                      
void setup() {
  //Serial.begin(9600);
    pinMode(op1, INPUT_PULLUP);     //For operation
    pinMode(op0, INPUT_PULLUP);     //For operation
    pinMode(x3,  INPUT_PULLUP);     //For number 1
    pinMode(x2,  INPUT_PULLUP);     //For number 1
    pinMode(x1,  INPUT_PULLUP);     //For number 1
    pinMode(x0,  INPUT_PULLUP);     //For number 1
    pinMode(y3,  INPUT_PULLUP);     //For number 2
    pinMode(y2,  INPUT_PULLUP);     //For number 2
    pinMode(y1,  INPUT_PULLUP);     //For number 2
    pinMode(y0,  INPUT_PULLUP);     //For number 2
    pinMode(sw1, INPUT);     
    pinMode(sw2, INPUT); 
    pinMode(12, OUTPUT); //For number  2   
    // set up the LCD's number of  columns and rows:
    lcd.begin(16, 2);
    //randomSeed(analogRead(0));
  }
 
     
                         

Then, in the Void Loop, I start by a welcome message and wait from an input of the sw1 or sw2

                    
                      
  lcd.clear();  lcd.clear();
  lcd.print("Welcome");
  lcd.setCursor(0, 1);
  lcd.print("Press the  key");
  while ( digitalRead(sw1)==0  && digitalRead(sw2)==0 ); // Wait for a key
 
     
                         

If the pushbutton 1 is pressed, it means its calculator mode, so I need to check the inputs x3,x2,x1, and x0 to determine which number is placed in the first slot, and using the y2,y3,y1 and y0, I identify which number was placed in slot 2. I also check for the operation, which will be a digital input op1 and op2, and depending on the operation selected, I call the method to calculate to find the answer and print it in the screen.

                    
                      
//CALCULATE THE OPERATION DEPENDING ON THE INPUT  0 AND 1. 00=/ 01=* 10=- and 11=+
 operation  =  !(digitalRead(op1))<<1 ;
    operation +=  !(digitalRead(op0))<<0 ;  //CALCULATE NUMBER 1 DEPENDING ON inputs  6,7,8,9  
    n1=   !(digitalRead(x3))<<3 ; 
    n1+= !(digitalRead(x2))<<2 ;
    n1+= !(digitalRead(x1))<<1 ;
    n1+= !(digitalRead(x0))<<0 ;
    if(n1==10)
      n1=0; 
       n2=  !(digitalRead(y3))<<3 ; 
    n2+= !(digitalRead(y2))<<2 ;
    n2+= !(digitalRead(y1))<<1 ;
    n2+= !(digitalRead(y0))<<0 ;
    if(n2==10)
      n2=0;
       lcd.setCursor(0,  1);\
    lcd.print(n1);
    if (operation == 0){  lcd.print("+");} else 
    if (operation == 1){  lcd.print("-");} else 
    if (operation == 2){  lcd.print("*");} else 
    if (operation == 3){  lcd.print("/");} 
    lcd.print(n2);   
    lcd.print("=");  
    ans = calculate(n1,n2,operation);
    lcd.print(ans);
    delay(400);
    }
 
     
                         

Method Calculate just returns the answer of the operation, which could be add, subtract, multiply or divide, depending on the inputs for operation,

                    
                      
//CALCULATE THE OPERATION DEPENDING ON THE INPUT  0 AND 1. 00=/ 01=* 10=- and 11=+
  int calculate ( int x, int y, int operate)
  {
    if (operate == 0){
        return x+y  ;
      }
      else if (operate ==  1){
        return x-y  ;
      }
    else if (operate == 2){
        return x*y  ;
      }
      else if (operate ==  3){
        return x/y  ;
      }
  }
 
     
                         

If the push button 2 is pressed, I call task 2,

                    
                      
else if ( digitalRead(sw2)==1 )
    {
    task2();
      lcd.setCursor(4, 0);
      lcd.print("Good  Job    ");
      digitalWrite(12,HIGH);
      delay(1500);
      digitalWrite(12, LOW);
    }
  }
 
     
                         

In task 2, I will display a random operation in the screen, and the student needs to select the correct answer and place it in the slot. For this, I generate a random operation, from 0to4, and 2 random numbers from 0 to 9. Internally, I calculate the answer, and then wait for the student to place the tile of the answer he thinks is true. I wait until the correct answer is placed in order to exit the while, and the turn on the LEDs and buzzer, meaning they got the right answer.

                    
                      
    void task2()
    {
    lcd.clear();
    lcd.print("Solve Me");
    operation = random(3);
    n1 = random(9);
    n2 = random(9);
    r_ans =  calculate(n1,n2,operation);
    lcd.setCursor(3, 1);
    lcd.print("=");
    lcd.print(r_ans);
    while ( true )
    {
      read_();
      if(n1!=0) // check if  there is a number
      {
        if(n1==10)
          n1=0;
        lcd.setCursor(0,  1);
        lcd.print(n1); 
      } 
      if(n2!=0)
      {
        if(n2==10)
          n2=0;      lcd.setCursor(2, 1);
        lcd.print(n2);    
    } 
      lcd.setCursor(1, 1);
      lcd.print(operation_sym[operation]);    
    ans =  calculate(n1,n2,operation);
      if (ans == r_ans)
      {
        return;
      }
    }
  }