Rotate the potentiometers in the correct sequence to access system!
Things used in this project
Hardware components
HARDWARE LIST
1 DFRobot I2C 16x2 Arduino LCD Display Module
1 Arduino UNO
4 LED, Green
4 Rotary potentiometer (generic)
4 Resistor 1k ohm
1 Resistor 220 ohm
1 Buzzer
1 Tactile Switch, Top Actuated
1 Jumper wires (generic)
1 Breadboard (generic)
Story
Ever watched the movie 'Army of Thieves' on Netflix?
This project was inspired by how the character in the movie open the vaults, and how intricate the combination locks on the vaults were.
I created it having three different sets of combination sequence.
If User input the correct first combination then access granted, else it will move on to the next stored combination sequence for the user to try again.
And if that is correct access granted, else it will move on to the last stored combination sequence for the user to try one final time.
When the User fails to enter three times in a row, the 'system' will shutdown.
Schematics
Circuit:
Schematic:
Code
CODE
/* Arduino 'Combination Safe' concept
Components:
- Arduino Uno
- Green LED (x 4)
- 10KOhm potentiometer (x 4)
- 1kOhm resistor (x 4)
- 220Ohm resistor
- LCD I2C (20x4)
- Passive Buzzer
- Push button tactile switch
- Some jumper wires
Libraries:
- LiquidCrystal_I2C library
Created on 29 June 2022 by c010rblind3ngineer
*/
#include <LiquidCrystal_I2C.h>
int pot1, pot2, pot3, pot4;
const int buzzer = 9;
const int buttonPin = 2;
////////////////////////////////////////////////////////////////////////////////
// LEDs are for visual indication of the correct input password, //
// for future project you could put numeric indicators on each potentiometer. //
////////////////////////////////////////////////////////////////////////////////
const int D1_LED = 7;
const int D2_LED = 6;
const int D3_LED = 5;
const int D4_LED = 4;
unsigned long firstDigitTime;
unsigned long lastDigitTime;
int timeLimit = 8000; // time limit for User to input combination
int i = 0;
int t = 0;
int load = 0;
int line;
int count;
int password[5] = {1, 2, 3, 4}; // set your own password here...
byte loadingBar[] = {
B11111,
B11111,
B11111,
B11111,
B11111,
B11111,
B11111,
B11111,
};
LiquidCrystal_I2C lcd(0x27, 20, 4);
void setup() {
Serial.begin(9600);
pinMode(D1_LED, OUTPUT);
pinMode(D2_LED, OUTPUT);
pinMode(D3_LED, OUTPUT);
pinMode(D4_LED, OUTPUT);
pinMode(buttonPin, INPUT);
lcd.init();
lcd.createChar(0, loadingBar);
}
void loop() {
//////////////////////////////////////////////////////////////
// There are 3 sets of 'Combination' functions: //
// Combination_original() ---->> pot#1, pot#2, pot#3, pot#4 //
// Combination_one() ---->> pot#1, pot#3, pot#2, pot#4 //
// Combination_two() ---->> pot#4, pot#3, pot#2, pot#1 //
//////////////////////////////////////////////////////////////
for (count = 0; count < 3;) {
if (count == 0) {
while (load < 1) {
safeInit();
load = 1;
}
Combination_original();
}
if (count == 1) {
while (load < 1) {
lcd.clear();
lcd.print("Press button once...");
while (digitalRead(buttonPin) != HIGH) {}
if (digitalRead(buttonPin) == HIGH) {
i = 0;
t = 0;
}
delay(100);
safeInit();
load = 1;
}
Combination_one();
}
if (count == 2) {
while (load < 1) {
lcd.clear();
lcd.print("Press button once...");
while (digitalRead(buttonPin) != HIGH) {}
if (digitalRead(buttonPin) == HIGH) {
i = 0;
t = 0;
}
delay(100);
safeInit();
load = 1;
}
Combination_two();
}
}
// if User fail to input combination within time limit for ALL tries, shutdown system...
delay(3000);
lcd.clear();
lcd.setCursor(0, 1);
lcd.print(" Goodbye. ");
delay(1000);
tone(buzzer, 2000);
delay(100);
noTone(buzzer);
delay(50);
tone(buzzer, 2000);
delay(100);
noTone(buzzer);
delay(50);
lcd.clear();
lcd.noBacklight();
}
// Initialization & Loading screen
void safeInit() {
lcd.backlight();
lcd.setCursor(0, 0);
lcd.print(" Arduino ");
lcd.setCursor(0, 1);
lcd.print(" Combination Safe ");
delay(5000);
lcd.clear();
lcd.print(" Loading... ");
delay(1000);
lcd.setCursor(0, 1);
for (line = 0; line < 20; line++) {
lcd.write(0);
delay(200);
}
delay(250);
tone(buzzer, 2000);
delay(100);
noTone(buzzer);
delay(50);
tone(buzzer, 2000);
delay(100);
noTone(buzzer);
delay(50);
lcd.clear();
lcd.setCursor(0, 1);
lcd.print(" Enter combination: ");
}
///////////////////////////Combination # Original/////////////////////////////
// Turn potentiometers in this sequence: //
// First - pot #1 //
// Second - pot #2 //
// Third - pot #3 //
// Fourth - pot #4 //
// *NOTE*: You can set your own combination sequence by changing the //
// arrangement of pot1_digact - pot4_digact in the 'if' //
// statements. //
//////////////////////////////////////////////////////////////////////////////
void Combination_original() {
while (i < 4) {
if (pot1_digact(password[0]) == 1) { // pot #1
digitalWrite(D1_LED, HIGH); // turn ON 1st LED
// capture time taken for the user to input the FIRST digit
while (t < 1) {
firstDigitTime = millis();
Serial.print("First Digit Time: ");
Serial.println(firstDigitTime);
t = 1;
}
i = 1;
if (pot2_digact(password[1]) == 1) { // pot #2
digitalWrite(D2_LED, HIGH); // turn ON 2nd LED
i = 2;
if (pot3_digact(password[2]) == 1) { // pot #3
digitalWrite(D3_LED, HIGH); // turn ON 3rd LED
i = 3;
if (pot4_digact(password[3]) == 1) { // pot #4
digitalWrite(D4_LED, HIGH); // turn ON 4th LED
t = 0; // re-enable 'timer'
// capture time taken for the user to input the LAST digit
while (t < 1) {
lastDigitTime = millis();
Serial.print("Last Digit Time: ");
Serial.println(lastDigitTime);
t = 1;
}
// Compare start and end timing if User enter password within the time limit
if (lastDigitTime - firstDigitTime < timeLimit) {
//ACCESS GRANTED HERE//
accessGranted();
}
else {
//ACCCESS DENIED HERE//
accessDenied();
count++;
load = 0;
}
delay(1000);
digitalWrite(D1_LED, LOW);
digitalWrite(D3_LED, LOW);
digitalWrite(D2_LED, LOW);
digitalWrite(D4_LED, LOW);
i = 4;
}
else {
digitalWrite(D4_LED, LOW);
}
}
else {
digitalWrite(D3_LED, LOW);
}
}
else {
digitalWrite(D2_LED, LOW);
}
}
else {
digitalWrite(D1_LED, LOW);
}
}
}
///////////////////////////Combination # ONE//////////////////////////////////
// Turn potentiometers in this sequence: //
// First - pot #1 //
// Second - pot #3 //
// Third - pot #2 //
// Fourth - pot #4 //
// *NOTE*: You can set your own combination sequence by changing the //
// arrangement of pot1_digact - pot4_digact in the 'if' //
// statements. //
//////////////////////////////////////////////////////////////////////////////
void Combination_one() {
while (i < 4) {
if (pot1_digact(password[0]) == 1) { // pot #1
digitalWrite(D1_LED, HIGH); // turn ON 1st LED
// capture time taken for the user to input the FIRST digit
while (t < 1) {
firstDigitTime = millis();
Serial.print("First Digit Time: ");
Serial.println(firstDigitTime);
t = 1;
}
i = 1;
if (pot3_digact(password[1]) == 1) { // pot #3
digitalWrite(D2_LED, HIGH); // turn ON 2nd LED
i = 2;
if (pot2_digact(password[2]) == 1) { // pot #2
digitalWrite(D3_LED, HIGH); // turn ON 3rd LED
i = 3;
if (pot4_digact(password[3]) == 1) { // pot #4
digitalWrite(D4_LED, HIGH); // turn ON 4th LED
t = 0; // re-enable 'timer'
// capture time taken for the user to input the LAST digit
while (t < 1) {
lastDigitTime = millis();
Serial.print("Last Digit Time: ");
Serial.println(lastDigitTime);
t = 1;
}
// Compare start and end timing if User enter password within the time limit
if (lastDigitTime - firstDigitTime < timeLimit) {
//ACCESS GRANTED HERE//
accessGranted();
}
else {
//ACCESS DENIED HERE//
accessDenied();
count++;
load = 0;
}
delay(1000);
digitalWrite(D1_LED, LOW);
digitalWrite(D3_LED, LOW);
digitalWrite(D2_LED, LOW);
digitalWrite(D4_LED, LOW);
i = 4;
}
else {
digitalWrite(D4_LED, LOW);
}
}
else {
digitalWrite(D3_LED, LOW);
}
}
else {
digitalWrite(D2_LED, LOW);
}
}
else {
digitalWrite(D1_LED, LOW);
}
}
}
///////////////////////////Combination # TWO//////////////////////////////////
// Turn potentiometers in this sequence: //
// First - pot #4 //
// Second - pot #3 //
// Third - pot #2 //
// Fourth - pot #1 //
// *NOTE*: You can set your own combination sequence by changing the //
// arrangement of pot1_digact - pot4_digact in the 'if' //
// statements. //
//////////////////////////////////////////////////////////////////////////////
void Combination_two() {
while (i < 4) {
if (pot4_digact(password[0]) == 1) { // pot #4
digitalWrite(D1_LED, HIGH); // turn ON 1st LED
// capture time taken for the user to input the FIRST digit
while (t < 1) {
firstDigitTime = millis();
Serial.print("First Digit Time: ");
Serial.println(firstDigitTime);
t = 1;
}
i = 1;
if (pot3_digact(password[1]) == 1) { // pot #3
digitalWrite(D2_LED, HIGH); // turn ON 2nd LED
i = 2;
if (pot2_digact(password[2]) == 1) { // pot #2
digitalWrite(D3_LED, HIGH); // turn ON 3rd LED
i = 3;
if (pot1_digact(password[3]) == 1) { // pot #1
digitalWrite(D4_LED, HIGH); // turn ON 4th LED
t = 0; // re-enable 'timer'
// capture time taken for the user to input the LAST digit
while (t < 1) {
lastDigitTime = millis();
Serial.print("Last Digit Time: ");
Serial.println(lastDigitTime);
t = 1;
}
// Compare start and end timing if User enter password within the time limit
if (lastDigitTime - firstDigitTime < timeLimit) {
//ACCESS GRANTED HERE//
accessGranted();
}
else {
//ACCESS DENIED HERE//
accessDenied();
count++;
}
delay(1000);
digitalWrite(D1_LED, LOW);
digitalWrite(D3_LED, LOW);
digitalWrite(D2_LED, LOW);
digitalWrite(D4_LED, LOW);
i = 4;
}
else {
digitalWrite(D4_LED, LOW);
}
}
else {
digitalWrite(D3_LED, LOW);
}
}
else {
digitalWrite(D2_LED, LOW);
}
}
else {
digitalWrite(D1_LED, LOW);
}
}
}
////////////////////////////////////////////////////////////////////////////
// This function turns the 1st potentiometer into a rotating dial (1 - 9) //
////////////////////////////////////////////////////////////////////////////
int pot1_digact(int val) {
pot1 = analogRead(A0);
// for 1st digit of the password
switch (val) {
case 1:
if ((val == 1) && pot1 >= 100 && pot1 <= 199) {
return 1;
}
else {
return 0;
}
break;
case 2:
if ((val == 2) && pot1 >= 200 && pot1 <= 399) {
return 1;
}
else {
return 0;
}
break;
case 3:
if ((val == 3) && pot1 >= 300 && pot1 <= 399) {
return 1;
}
else {
return 0;
}
break;
case 4:
if ((val == 4) && pot1 >= 400 && pot1 <= 499) {
return 1;
}
else {
return 0;
}
break;
case 5:
if ((val == 5) && pot1 >= 500 && pot1 <= 599) {
return 1;
}
else {
return 0;
}
break;
case 6:
if ((val == 6) && pot1 >= 600 && pot1 <= 699) {
return 1;
}
else {
return 0;
}
break;
case 7:
if ((val == 7) && pot1 >= 700 && pot1 <= 799) {
return 1;
}
else {
return 0;
}
break;
case 8:
if ((val == 8) && pot1 >= 800 && pot1 <= 899) {
return 1;
}
else {
return 0;
}
break;
case 9:
if ((val == 9) && pot1 >= 900) {
return 1;
}
else {
return 0;
}
break;
}
}
////////////////////////////////////////////////////////////////////////////
// This function turns the 2nd potentiometer into a rotating dial (1 - 9) //
////////////////////////////////////////////////////////////////////////////
int pot2_digact(int val) {
pot2 = analogRead(A1);
// for 2nd digit of the password
switch (val) {
case 1:
if ((val == 1) && pot2 >= 100 && pot2 <= 199) {
return 1;
}
else {
return 0;
}
break;
case 2:
if ((val == 2) && pot2 >= 200 && pot2 <= 399) {
return 1;
}
else {
return 0;
}
break;
case 3:
if ((val == 3) && pot2 >= 300 && pot2 <= 399) {
return 1;
}
else {
return 0;
}
break;
case 4:
if ((val == 4) && pot2 >= 400 && pot2 <= 499) {
return 1;
}
else {
return 0;
}
break;
case 5:
if ((val == 5) && pot2 >= 500 && pot2 <= 599) {
return 1;
}
else {
return 0;
}
break;
case 6:
if ((val == 6) && pot2 >= 600 && pot2 <= 699) {
return 1;
}
else {
return 0;
}
break;
case 7:
if ((val == 7) && pot2 >= 700 && pot2 <= 799) {
return 1;
}
else {
return 0;
}
break;
case 8:
if ((val == 8) && pot2 >= 800 && pot2 <= 899) {
return 1;
}
else {
return 0;
}
break;
case 9:
if ((val == 9) && pot2 >= 900) {
return 1;
}
else {
return 0;
}
break;
}
}
////////////////////////////////////////////////////////////////////////////
// This function turns the 3rd potentiometer into a rotating dial (1 - 9) //
////////////////////////////////////////////////////////////////////////////
int pot3_digact(int val) {
pot3 = analogRead(A2);
// for 3rd digit of the password
switch (val) {
case 1:
if ((val == 1) && pot3 >= 100 && pot3 <= 199) {
return 1;
}
else {
return 0;
}
break;
case 2:
if ((val == 2) && pot3 >= 200 && pot3 <= 399) {
return 1;
}
else {
return 0;
}
break;
case 3:
if ((val == 3) && pot3 >= 300 && pot3 <= 399) {
return 1;
}
else {
return 0;
}
break;
case 4:
if ((val == 4) && pot3 >= 400 && pot3 <= 499) {
return 1;
}
else {
return 0;
}
break;
case 5:
if ((val == 5) && pot3 >= 500 && pot3 <= 599) {
return 1;
}
else {
return 0;
}
break;
case 6:
if ((val == 6) && pot3 >= 600 && pot3 <= 699) {
return 1;
}
else {
return 0;
}
break;
case 7:
if ((val == 7) && pot3 >= 700 && pot3 <= 799) {
return 1;
}
else {
return 0;
}
break;
case 8:
if ((val == 8) && pot3 >= 800 && pot3 <= 899) {
return 1;
}
else {
return 0;
}
break;
case 9:
if ((val == 9) && pot3 >= 900) {
return 1;
}
else {
return 0;
}
break;
}
}
////////////////////////////////////////////////////////////////////////////
// This function turns the 4th potentiometer into a rotating dial (1 - 9) //
////////////////////////////////////////////////////////////////////////////
int pot4_digact(int val) {
pot4 = analogRead(A3);
// for 4th digit of the password
switch (val) {
case 1:
if ((val == 1) && pot4 >= 100 && pot4 <= 199) {
return 1;
}
else {
return 0;
}
break;
case 2:
if ((val == 2) && pot4 >= 200 && pot4 <= 399) {
return 1;
}
else {
return 0;
}
break;
case 3:
if ((val == 3) && pot4 >= 300 && pot4 <= 399) {
return 1;
}
else {
return 0;
}
break;
case 4:
if ((val == 4) && pot4 >= 400 && pot4 <= 499) {
return 1;
}
else {
return 0;
}
break;
case 5:
if ((val == 5) && pot4 >= 500 && pot4 <= 599) {
return 1;
}
else {
return 0;
}
break;
case 6:
if ((val == 6) && pot4 >= 600 && pot4 <= 699) {
return 1;
}
else {
return 0;
}
break;
case 7:
if ((val == 7) && pot4 >= 700 && pot4 <= 799) {
return 1;
}
else {
return 0;
}
break;
case 8:
if ((val == 8) && pot4 >= 800 && pot4 <= 899) {
return 1;
}
else {
return 0;
}
break;
case 9:
if ((val == 9) && pot4 >= 900) {
return 1;
}
else {
return 0;
}
break;
}
}
void accessGranted() {
lcd.clear();
lcd.setCursor(0, 1);
lcd.print(" Access Granted ");
digitalWrite(D1_LED, LOW);
digitalWrite(D3_LED, LOW);
digitalWrite(D2_LED, LOW);
digitalWrite(D4_LED, LOW);
tone(buzzer, 2000);
digitalWrite(D1_LED, HIGH);
digitalWrite(D3_LED, HIGH);
digitalWrite(D2_LED, HIGH);
digitalWrite(D4_LED, HIGH);
delay(100);
digitalWrite(D1_LED, LOW);
digitalWrite(D3_LED, LOW);
digitalWrite(D2_LED, LOW);
digitalWrite(D4_LED, LOW);
noTone(buzzer);
delay(100);
digitalWrite(D1_LED, HIGH);
digitalWrite(D3_LED, HIGH);
digitalWrite(D2_LED, HIGH);
digitalWrite(D4_LED, HIGH);
tone(buzzer, 2000);
delay(100);
noTone(buzzer);
delay(100);
}
void accessDenied() {
lcd.clear();
lcd.setCursor(0, 1);
lcd.print(" Access Denied ");
tone(buzzer, 1000);
delay(250);
noTone(buzzer);
delay(100);
tone(buzzer, 1000);
delay(250);
noTone(buzzer);
delay(100);
tone(buzzer, 1000);
delay(250);
noTone(buzzer);
delay(100);
lcd.clear();
lcd.setCursor(0, 0);
lcd.print(" Please reset ");
lcd.setCursor(0, 1);
lcd.print("ALL FOUR knobs to 0");
lcd.setCursor(0, 2);
for (line = 0; line < 20; line++) {
lcd.write(0);
delay(1000);
}
}Repository link:
Arduino-Combination-Safe-master.zip The article was first published in hackster, June 29, 2022
cr: https://www.hackster.io/c010rblind3ngineer/arduino-combination-safe-ac2c97
author: c010rblind3ngineer
License 
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