// This one was a little bit trick, but only because of the female connectors. 

#include <Servo.h>

Servo myServo;

const int piezo = A0;
const int switchPin = 2;
const int yellowLed = 3;
const int greenLed = 4;
const int redLed = 5;
int knockVal;
int switchVal;
const int quietKnock = 10;
const int loudKnock = 100;
bool locked = false;
int numberOfKnocks = 0;

void setup() {
  myServo.attach(9);
  pinMode(yellowLed, OUTPUT);
  pinMode(redLed, OUTPUT);
  pinMode(greenLed, OUTPUT);

  pinMode(switchPin, INPUT);

  Serial.begin(9600);

  digitalWrite(greenLed, HIGH);

  myServo.write(0);

  Serial.println("the box is unlocked!");
}

void loop() {

  if (locked == false) {

    switchVal = digitalRead(switchPin);

    if (switchVal == HIGH) {
      locked = true;

      digitalWrite(greenLed, LOW);
      digitalWrite(redLed, HIGH);

      myServo.write(90);

      Serial.println("the box is locked!");

      delay(1000);
    }
  }


  if (locked == true) {

    
    knockVal = analogRead(piezo);

    if (numberOfKnocks < 3 && knockVal > 0) {

      if (checkForKnock(knockVal) == true) {

      
        numberOfKnocks++;
      }

     
      Serial.print(3 - numberOfKnocks);
      Serial.println(" more knocks to go");
    }

    /
    if (numberOfKnocks >= 3) {
    
      locked = false;


      myServo.write(0);

      delay(20);

      digitalWrite(greenLed, HIGH);
      digitalWrite(redLed, LOW);
      Serial.println("the box is unlocked!");

      numberOfKnocks = 0;
    }
  }
}

bool checkForKnock(int value) {

  if (value > quietKnock && value < loudKnock) {
  
    digitalWrite(yellowLed, HIGH);
    delay(50);
    digitalWrite(yellowLed, LOW);
   
    Serial.print("Valid knock of value ");
    Serial.println(value);
 
    return true;
  }
 
    Serial.print("Bad knock value ");
    Serial.println(value);
    return false;
  }
}