Description

Use Arduino and Processing to create a virtual combination lock

Components Used

3 Light Emitting Diodes (LED)

3 Resistors

1 Potentiometer

Arduino Code

  /*
** Joshua Gomez - Lab 4
**
** This code will attempt to make a POT into a dial for a combination lock
** The LEDs will be used as hints that the correct position has been reached
** The combination is 50-15-30
*/

int potPin = 1;    // select the input pin for the potentiometer
int ledPin1 = 9;   // select the pins for the LEDs
int ledPin2 = 11;
int ledPin3 = 13;
int input = 0;       // variable to store the value coming from the sensor

boolean step1 = false;  // variables to keep track of progress
boolean step2 = false;

int val1 = 50;      // combo lock settings
int val2 = 15;
int val3 = 30;

void setup() {
  pinMode(ledPin1, OUTPUT);  // declare the ledPins as an OUTPUT
  pinMode(ledPin2, OUTPUT);
  pinMode(ledPin3, OUTPUT);
 
  Serial.begin(9600);
}

void loop() {
  input = analogRead(potPin);    // read the value from the sensor between 0-1024
  input = input/17;                // scale value down to combo lock's range: 0-60
  Serial.println(input);         // send value to Processing

  if (step1==false && input==val1)
  {
    digitalWrite(ledPin1, HIGH);  // if the first number is reached light the first LED
    step1 = true;
  }
 
  if (step1==true && step2==false && input==val2)
  {
    digitalWrite(ledPin2, HIGH);
    step2 = true;
    digitalWrite(ledPin1, LOW);
  }
 
  if ( step2==true && input==val3)
  {
    digitalWrite(ledPin3, HIGH);
    digitalWrite(ledPin2, LOW);
  }
    

}

Processing Code

  /*
 * Joshua Gomez - Lab 4
 *
 * This program will display the face of a combination lock
 * The input from the serial port will determine the position of the dial
 * When the lock opens and a fun image appears
 */

import processing.serial.*;

Serial port;  // Create object from Serial class
String portname = "/dev/ttyUSB0";

int cr = 13;  // ASCII carriage return
int lf = 10;  // ASCII line feed
String buf = "";  // input buffer

int position = 0;  // position of the dial
int numPos = 12;    // number of positions on the dial (I use 12 instead of 60 to make it easier)

PImage[] lock = new PImage[numPos + 1];  // array for the images of the combo lock, plus the final image

boolean step1 = false;  // variables to keep track of progress
boolean step2 = false;
int val1 = 50;          // set up the lock's combination
int val2 = 15;
int val3 = 30;
int prev = 0;            // helps keep track of rotation

/****************************************************************************************/

void setup()
{
  size(162, 163);
  frameRate(10);
 
  lock[0] = loadImage("combo_lock_0.jpg");  //load the animation frames of the lock
  lock[1] = loadImage("combo_lock_1.jpg");
  lock[2] = loadImage("combo_lock_2.jpg");
  lock[3] = loadImage("combo_lock_3.jpg");
  lock[4] = loadImage("combo_lock_4.jpg");
  lock[5] = loadImage("combo_lock_5.jpg");
  lock[6] = loadImage("combo_lock_6.jpg");
  lock[7] = loadImage("combo_lock_7.jpg");
  lock[8] = loadImage("combo_lock_8.jpg");
  lock[9] = loadImage("combo_lock_9.jpg");
  lock[10] = loadImage("combo_lock_10.jpg");
  lock[11] = loadImage("combo_lock_11.jpg");
  lock[12] = loadImage("happy.jpg");
 
  image(lock[0], 0, 0);  // load the first image
 
  port = new Serial(this, portname, 9600);
 
}

void draw()
{
}

void SerialEvent(Serial p)
{
  int c = port.read();
  println("test");
  if (c != lf && c != cr)
  {
    buf += char(c);
  }
 
  if (c == lf)
  {
    String input = buf;
    println(input);
    position = int(input);
    int frame = position/5;
    image(lock[frame], 0, 0);
    
    if(step1==false && position==val1 && prev<=position)
      step1=true;
    if(step1==true && step2==false && position==val2 && prev>=position)
      step2=true;
    if(step2==true && position==val3 && prev<=position)
    {
      image(lock[12], 0, 0);    // when step 3 is reached show the happy face
      step1=false;        // reset the lock
      step2=false;
    }
    
    prev = position;
    buf = "";
    
  }
}

Item 

ComboLock Arduino

Combo Lock Screenshot

Combo Loc

Happy Face

Part II

For the mechanical part of the lab, I searched the house for an alternate way of pressing the FSR. I settled on using my girlfriend's curling iron (not plugged in of course) with some packing bubbles between the FSR and the iron to distribute the force. Here is a picture (bubbles not included so you can see the FSR). 

FSR depresser/ force distributor