knock-lock using servo motor

knock-lock

#include <Servo.h> //Include the Servo Library

Servo myServo;

//Name the input/ouput
const int piezo = A0;
const int switchPin = 2;
const int yellowLed = 3;
const int redLed = 4;
const int greenLed = 5;

//Setuo constants to hold throshold for knocks
int knockVal;
int switchVal;

const int quietKnock = 10;
const int loudKnock = 100;

boolean locked = false;
int numberOfKnocks  = 0;

//Connect servo to pin 9, set pin mode to input and output
void setup(){
 myServo.attach(9);
 pinMode(yellowLed, OUTPUT);
 pinMode(redLed, OUTPUT);
 pinMode(greenLed, OUTPUT);
 pinMode(switchPin, INPUT);
 Serial.begin(9600); //initialize serial communication with the computer
 digitalWrite(greenLed,HIGH);
 myServo.write(0);
 Serial.println("The box is unlocked!");
}

void loop(){
if(locked == false){  //if unlocked lock it using switch
  switchVal = digitalRead(switchPin);
  if(switchVal == HIGH)
    {
      locked = true;
      digitalWrite(greenLed,LOW);  //set green led to low
      digitalWrite(redLed,HIGH);  //set red led to high
      myServo.write(90); //Turn 90 degree 
      Serial.println("The box is locked!");
      delay(1000);
    }
  }  //if ends
  if(locked == true){  //if locked, then read knocks using peizo
    knockVal = analogRead(piezo);
    if(numberOfKnocks < 3 && knockVal > 0)
    {
      if(checkForKnocks(knockVal)==true){
        numberOfKnocks++;
      }
      Serial.print(3 - numberOfKnocks);
      Serial.println("more kncoks to go");
      
    }
    if(numberOfKnocks >= 3){
     locked = false;
     myServo.write(0);
     delay(20);
     digitalWrite(greenLed,HIGH);  
     digitalWrite(redLed,LOW);  
     Serial.println("The box is unlocked!");
    }
  }
}


boolean checkForKnocks(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;
  }
  else
  {
     Serial.print("Bad knock Value ");
     Serial.println(value);
     return false;
  }
}