// For this circuit make sure you have an LED and a 100-300 ohm 
// Reaction time game!
// Author: David Hogg

// Uses the Grove - Button to control the Grove - LED.
// Connect the Grove - Button to the socket marked D3
// Connect the Grove - LED to D7

// Defines the pins to which the button and LED are connected.
const int pinButton = 3;
const int pinLed    = 7;

long randNumber;
long startTime;
long endTime;
boolean bStart;

void startGame() {
    // Start with light OFF.
    digitalWrite(pinLed, LOW);

    bStart = true;  

    // Start message
    Serial.println("Get Ready. Watch the light...");
    Serial.println(" -> Click Button when it goes on!");
}

void setup()
{
    // Setup the serial monitor
    Serial.begin(9600);
    
    // Seed random number generator
    randomSeed(analogRead(0));
    
    // Configure the button's pin for input signals.
    pinMode(pinButton, INPUT);

    // Configure the LED's pin for output.
    pinMode(pinLed, OUTPUT);

    // Call the start game function.
    startGame();    
}

void loop()
{
    if (bStart) {
      // Wait for between .5 seconds and 5 seconds!
      randNumber = random(500, 5000);
      delay(randNumber);
  
      // Turn ON the light and get start time.
      digitalWrite(pinLed, HIGH);
      startTime = millis();

      bStart = false;
    }    

    // NOW check for when person clicks button!     
    if(digitalRead(pinButton))
    {
        // Person had pressed the button! Calculate reaction time.
        endTime = millis();
        long reactTime = endTime - startTime;

        Serial.println("Your Reaction Time....");
        Serial.print(reactTime);
        Serial.println(" ms");

        delay(3000);

        // Play again!
        startGame();
    }
}