/*
  Arduino calculator with keypad and LCD, and quiz
  Tom Tobback Oct 2017

  keypad library:
 || @version 1.0
 || @author Andrew Mascolo
 || @date May 15, 2013
 || @description
 || Simple use of keypad and LCD
 taken from https://playground.arduino.cc/Main/KeypadCalculator

 use LCD 16x2 with pot
 buzzer on D13
 keypad on D2-D9
 use * as decimal point

 starts as normal calculator
 enter magic number to start quiz: 60 seconds
 enter reset code to reset high score
*/

#include <EEPROM.h>        // for high score
#include <Keypad.h>
#include <LiquidCrystal.h>

// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(12, 11, A5, A4, A3, A2);


float first = 0;
float second = 0;
float total = 0;
boolean mult = false;       // multiplication flag to avoid overflow
boolean first_decimal = false;  // does the first number have a decimal point
int first_decimal_pos = 0; // how many digits after decimal point
boolean second_decimal = false;  // does the second number have a decimal point
int second_decimal_pos = 0; // how many digits after decimal point
int digits_first = 0;
int digits_second = 0;
const long magic_number = 321;     // to enter the quiz state
const long magic_reset = 332211;   // to reset high score
boolean quiz = false;             // quiz state
int answer;                       // quiz answer
int correct_answer;               // correct quiz answer
int digits_answer = 0;            // count digits of answer
int score = 0;
unsigned long timestamp = 0;      // start of quiz
int high_score;
char customKey;
const byte ROWS = 4;
const byte COLS = 4;

char keys[ROWS][COLS] = {
 {'1', '2', '3', '+'},
 {'4', '5', '6', '-'},
 {'7', '8', '9', '*'},
 {'.', '0', '=', '/'}
};
byte rowPins[ROWS] = {2, 3, 4, 5}; //connect to the row pinouts of the keypad
byte colPins[COLS] = {6, 7, 8, 9}; //connect to the column pinouts of the keypad

//initialize an instance of class NewKeypad
Keypad customKeypad = Keypad( makeKeymap(keys), rowPins, colPins, ROWS, COLS);

void setup()
{
 //  EEPROM.write(10, 0);            // OPTIONAL reset high score to 0
 high_score = EEPROM.read(10);
 if (high_score == 255) {
   EEPROM.write(10, 0);            // reset high score to 0
   high_score = 0;
 }

 randomSeed(analogRead(A0));
 Serial.begin(9600);
 lcd.begin(16, 2);
 lcd.setCursor(2, 0);
 lcd.print("BuffaloLabs");
 lcd.setCursor(0, 1);
 lcd.print("Calculator+Quiz");
 tone(13, 500);
 delay(100);
 tone(13, 1000);
 delay(100);
 noTone(13);
 delay(2000);
 lcd.clear();
}

void loop()
{

 customKey = customKeypad.getKey();

 if (quiz) {                                 // quiz waiting for answer
   lcd.setCursor(14, 1);
   int remaining = 60 - (millis() - timestamp) / 1000;
   if (remaining < 10) lcd.print(" "); lcd.print(remaining); if (remaining == 0) { // quiz FINISHED if (score > high_score) {                       // new high score
       high_score = score;
       EEPROM.write(10, high_score);
       lcd.clear();
       lcd.print("NEW HIGH SCORE= ");
       lcd.setCursor(0, 1);
       lcd.print(high_score);
       for (int i = 1000; i < 4000; i += 5) { // siren tone(13, i); delay(1); } for (int i = 4000; i > 1000; i -= 5) {
         tone(13, i);
         delay(1);
       }
       noTone(13);
     }
     else {                                          // no new high score
       for (int i = 0; i < 10; i++) {
         tone(13, 2000);
         delay(50);
         noTone(13);
         delay(50);
       }
     }
     customKeypad.waitForKey();                      // new quiz
     beep();
     score = 0;
     showHighscore();
     correct_answer = quizQuestion();
     timestamp = millis();
   }

   switch (customKey)
   {
     case '0' ... '9':
       if (digits_answer < 4) { answer = answer * 10 + (customKey - '0'); // if integer (from ascii to numerical value) lcd.setCursor(digits_answer, 1); lcd.print(customKey); digits_answer++; beep(); Serial.println(answer, 6); } else { lowBeep(); } break; case '=': if (digits_answer > 0) {
         if (answer == correct_answer) {
           beepYes();
           score++;
         }
         else {
           beepNo();
           score--;
           if (score < 0) score = 0;
         }
         correct_answer = quizQuestion();
       }
       else {
         lowBeep();
       }
       break;
     case '+':
       lowBeep();
       break;
     case '-':
       lowBeep();
       break;
     case '*':
       lowBeep();
       break;
     case '/':
       lowBeep();
       break;
     case '.':
       lowBeep();
       break;
   }
 }

 else {                                      // normal calculator
   switch (customKey)
   {
     case '0' ... '9': // This keeps collecting the first value until a operator is pressed "+-*/"
       if (digits_first == 0) lcd.clear();
       if (digits_first < 6) { if (first_decimal) { first_decimal_pos++; float divider = pow(10, first_decimal_pos); first = first + (customKey - '0') / divider; } else { first = first * 10 + (customKey - '0'); // if integer (from ascii to numerical value) } lcd.print(customKey); digits_first++; beep(); Serial.println(first, 6); } else { lowBeep(); } if (first == magic_number) { // escape to quiz showHighscore(); correct_answer = quizQuestion(); quiz = true; timestamp = millis(); } if (first == magic_reset) { // reset quiz high score showReset(); char rst = customKeypad.waitForKey(); if (rst == '0') { EEPROM.write(10, 0); high_score = 0; longBeep(); } else { lowBeep(); } showHighscore(); correct_answer = quizQuestion(); quiz = true; timestamp = millis(); } break; case '+': if (digits_first == 0) { lowBeep(); break; } lcd.print("+"); beep(); second = SecondNumber(); // get the collected the second number lcd.print("="); beep(); total = first + second; printTotal(); break; case '-': if (digits_first == 0) { lowBeep(); break; } lcd.print("-"); beep(); second = SecondNumber(); lcd.print("="); beep(); total = first - second; printTotal(); break; case '*': if (digits_first == 0) { lowBeep(); break; } lcd.print("*"); beep(); mult = true; second = SecondNumber(); lcd.print("="); beep(); total = first * second; printTotal(); mult = false; break; case '/': if (digits_first == 0) { lowBeep(); break; } lcd.print("/"); beep(); second = SecondNumber(); lcd.print("="); beep(); second == 0 ? lcd.print("Invalid") : total = (float)first / (float)second; printTotal(); break; case '.': if (digits_first == 0) { lowBeep(); break; } if (first_decimal) { // already has decimal point lowBeep(); } else { lcd.setCursor(digits_first, 0); // add decimal point lcd.print(customKey); digits_first++; beep(); first_decimal = true; } break; case '=': lowBeep(); resetC(); lcd.clear(); break; } } } float SecondNumber() { while ( 1 ) { customKey = customKeypad.getKey(); if (customKey >= '0' && customKey <= '9') {
     if (digits_second < 6) {
       if ((mult && (digits_first + digits_second) < 10) || !mult) {
         lcd.print(customKey);
         beep();
         if (second_decimal) {
           second_decimal_pos++;
           float divider = pow(10, second_decimal_pos);
           second = second + (customKey - '0') / divider;
         }
         else {
           second = second * 10 + (customKey - '0');  // if integer    (from ascii to numerical value)
         }
         digits_second++;
         Serial.println(second, 6);
       }
       else {
         lowBeep();
       }
     }
     else {
       lowBeep();
     }
   }
   if (customKey == '=') break; //return second;

   if (customKey == '.') {
     if (second_decimal) {                    // already has decimal point
       lowBeep();
     }
     else {
       lcd.print(customKey);
       digits_second++;
       beep();
       second_decimal = true;
     }

   }
   if (customKey == '+' || customKey == '-' || customKey == '*' || customKey == '/' ) lowBeep();


 }
 return second;
}

void resetC() {
 total = 0;
 digits_first = 0; digits_second = 0;
 first = 0, second = 0;  // reset values back to zero for next use
 first_decimal = false;
 first_decimal_pos = 0;
 second_decimal = false;
 second_decimal_pos = 0;
}

void printTotal() {
 int decimalPlaces;
 float temp = total;
 for (decimalPlaces = 0; decimalPlaces < 7; decimalPlaces++) { if (temp == (long)temp) break; temp *= 10.0; // Shift left one decimal digit } Serial.println(total, decimalPlaces); lcd.setCursor(0, 1); lcd.print(total, decimalPlaces); resetC(); } void beep() { tone(13, 500); delay(10); noTone(13); } void lowBeep() { tone(13, 50); // low beep delay(10); noTone(13); } void longBeep() { tone(13, 500); // long beep delay(1000); noTone(13); } /////////////////////////////////////////////////////////////////////////////////////////////////////// /////////////////////////////////////////////////////////////////////////////////////////////////////// /////////////////////////////////////////////////////////////////////////////////////////////////////// int quizQuestion() { delay(random(0, 100)); randomSeed(analogRead(A0)); lcd.clear(); answer = 0; digits_answer = 0; int upper_limit = score / 2 + 5; first = random(score / 2 + 1, upper_limit); delay(random(0, 100)); randomSeed(analogRead(A0)); delay(random(0, 100)); int op = score % 4; // 0 1 2 3 switch (op) { case 0: lcd.print(first, 0); // float but show as int lcd.print("+"); second = random(1, upper_limit - 1); correct_answer = first + second; break; case 1: lcd.print(first, 0); // float but show as int lcd.print("-"); second = random(1, first + 1); correct_answer = first - second; break; case 2: lcd.print(first, 0); // float but show as int lcd.print("*"); if (first > 10) {
       second = 2;
     }
     else {
       second = random(0, 11);
     }
     correct_answer = first * second;
     break;
   case 3:                    // correct_answer = first >> (first * second) / second = first
     second = random(1, first + 1);
     correct_answer = first;
     lcd.print(first * second, 0);              // float but show as int
     lcd.print("/");
     break;
 }
 lcd.print(second, 0);              // float but show as int
 lcd.print("=");

 lcd.setCursor(8, 0);
 lcd.print("score:");
 if (score < 10) lcd.print(" ");
 lcd.print(score);

 lcd.setCursor(9, 1);
 lcd.print("time:");

 lcd.setCursor(0, 1);
 return correct_answer;
}

///////////////////////////////////////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////////////////////////////////////


void beepYes() {
 for (int i = 0; i < 3; i++) {
   tone(13, 1000);
   delay(50);
   noTone(13);
   delay(50);
 }
}

void beepNo() {
 for (int i = 0; i < 3; i++) {
   tone(13, 100);
   delay(50);
   noTone(13);
   delay(50);
 }
}

void showHighscore() {
 lcd.clear();
 lcd.print("HIGH SCORE= ");
 lcd.print(high_score);
 lcd.setCursor(0,1);
 lcd.print("starting quiz..");
 delay(2000);
 lcd.clear();

 tone(13, 500);
 delay(100);
 tone(13, 1000);
 delay(100);
 noTone(13);
}

void showReset() {
 lcd.clear();
 lcd.print("HIGH SCORE= ");
 lcd.print(high_score);
 lcd.setCursor(0, 1);
 lcd.print("Press 0 to reset...");
}