IoannisD
Published © GPL3+

Ultrasonic Lock

Anything can be used as a key as long as you know the password.

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Ultrasonic Lock

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Story

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Schematics

Ultrasonic Lock-Schematic

Code

Ultrasonic Lock-Code

C/C++
#include<Servo.h>
#include<LiquidCrystal.h>

LiquidCrystal lcd(12,11,5,4,3,2);
Servo myServo;

const int trigPin = 6;
const int echoPin = 7;
const int sound = 340;

float duration;
float distance;
float distanceLoop;
int pass[] = {8,7,6,5};//password numbers
int checkPass[5];//array with 4 values(initial every elemnet is equal with 0)
int number;
int count = 0;
int sizeArray;
float distanceCheck;// to check when it is ready to close box

void setup(){
  Serial.begin(9600);
  lcd.begin(16,2);
  myServo.attach(9);
  pinMode(trigPin,OUTPUT);
  pinMode(echoPin,INPUT);
  sizeArray = sizeof(pass)/2;//size of array
  int checkPass[5];
  lcd.print("Password:");
  myServo.write(120);
  delay(1000);
}

void loop(){
  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print("Password:");
  lcd.setCursor(1,0);
  for(int num = 0; num <= sizeArray ; num ++){//takes enough measurements(password keys) as the number of elements of password
    for(int i = 3; i > 1 ;i--){//countdown before a measurement(password key) is taken
      lcd.setCursor(15,0);
      lcd.print(i);
      lcd.setCursor(12,2);
      lcd.print(Distance());
      delay(1000);
    }
    distanceLoop = Distance();//measurement is taken
    number = check(distanceLoop,pass[num]);//rounds up number
    checkPass[num] = number;//assigns measurement to the array
    lcd.setCursor(num + 1,2);
    lcd.print(number);
  }
  for(int i = 0; i < 4 ; i ++){
    Serial.println(checkPass[i]);
  }
  count = checkCount(0,checkPass,pass,3);/*compares 2 arrays to check if the password is correct
                                         for every wrong value count variable increase by one*/
  if(count != 0){
    lcd.clear();
    lcd.print("Wrong Password");
    myServo.write(120);
    delay(5000);
  }
  else{
    lcd.clear();
    lcd.print("Valid Password");
    myServo.write(30);
    distanceCheck = Distance();
    while(distanceCheck > 5){
      distanceCheck = Distance();
      myServo.write(30);
      delay(500);
    }
    myServo.write(120);
    delay(1000);
  }
}

float Distance(){//measures distance in cm
  digitalWrite(trigPin,LOW);
  delayMicroseconds(15);
  digitalWrite(trigPin,HIGH);
  delayMicroseconds(2000);
  digitalWrite(trigPin,LOW);
  delayMicroseconds(10);
  duration = pulseIn(echoPin,HIGH);
  distance = sound * duration/20000;
  return distance;
}

int check(float msr,float nUm){//rounds up number
  if(msr >= nUm - 0.5 && msr <= nUm + 0.5){
    msr = nUm; 
    return msr; 
  }
  else{
    return (int) msr;
    
  }
}

int checkCount(int cnt,int checkPass[],int pass[],int times){//check password
  for(int num = 0; num <= times ; num ++){
    if(checkPass[num] == pass[num]){
      cnt = cnt;
    }
    else{
      cnt += 1;
    }
  }  
  return cnt;
}

Credits

IoannisD

IoannisD

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