16 – Secret Knock Lock

 

#include <Servo.h>
Servo servo9;
 
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;
boolean locked = false;
int numberOfKnocks = 0;
 
void setup() {
  servo9.attach(9);
  pinMode(yellowLed, OUTPUT);
  pinMode(greenLed, OUTPUT);
  pinMode(redLed, OUTPUT);
  pinMode(switchPin, INPUT);
  Serial.begin(9600);
 
  digitalWrite(greenLed, HIGH);
  servo9.write(0);
  Serial.println("The door is unlocked!");
}
 void loop() {
  if(locked == false) {
    switchVal = digitalRead(switchPin);
    if(switchVal == HIGH) {
      locked = true;
      digitalWrite(greenLed, LOW);
      digitalWrite(redLed, HIGH);
      servo9.write(90);
      Serial.println("The door 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;
      servo9.write(0);
      delay(20);
      digitalWrite(greenLed, HIGH);
      digitalWrite(redLed, LOW);
      Serial.println("The door is unlocked!");
    }
  }
}
 boolean 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;
  }
   else {
    Serial.print("Bad knock value ");
    Serial.println(value);
    return false;
  }
}

 

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