Code input system

Sometimes you have to enter a code into an ATM or a door system:

It can be easily stolen with a spy camera:

Of course code can be difficult to defend against real "proficient" ...

But! This gives more safety:

Code input basic system: You need:
-Arduino nano (or other)
-1   7 segment display (common cathod)
-1   74HC595 IC
-5   LED
-2   220-470 ohm resistors (or only one...)
-1   4,7 Kohm resistor
-2   buttons
-wires

Connects:

Arduino code (with 7 segment display):


int array[10] = {1,2,3,4,5,6,7,8,9,10} ;
int klick = -1;
int digit1a = 7;
int digit2a = 0;
int digit3a = 4;
int digit4a = 0;
int digit1b = 0;
int digit2b = 0;
int digit3b = 0;
int digit4b = 0;
int counter = 0;

int latchPin = 2;  //Pin connected to ST_CP of 74HC595
int clockPin = 4;  //Pin connected to SH_CP of 74HC595
int dataPin = 3;   //Pin connected to DS of 74HC595
//for 74595

void setup(){
 Serial.begin(9600);
// serial port optional, not need

 pinMode(5, INPUT);
 digitalWrite(5, HIGH);
  pinMode(6, INPUT);
 digitalWrite(6, HIGH);
 //belso felhuzo
 pinMode(7, OUTPUT);
 digitalWrite(7, LOW);
 // code in succeer green LED off
  pinMode(8, OUTPUT);
 digitalWrite(8, LOW);
 // digit 1 LED
  pinMode(9, OUTPUT);
 digitalWrite(9, LOW);
 // digit 2 LED
  pinMode(10, OUTPUT);
 digitalWrite(10, LOW);
 // digit 3 LED
   pinMode(11, OUTPUT);
 digitalWrite(11, LOW);
// digit 4 LED
 pinMode(latchPin, OUTPUT);
 pinMode(clockPin, OUTPUT);
 pinMode(dataPin, OUTPUT);
// for 74595
}

void loop(){


if (array[klick]-1 == 0) {
   digitalWrite(latchPin, LOW);
    shiftOut(dataPin, clockPin, MSBFIRST, 63);
    digitalWrite(latchPin, HIGH);
}

if (array[klick]-1 == 1) {
    digitalWrite(latchPin, LOW);
    shiftOut(dataPin, clockPin, MSBFIRST, 6);
    digitalWrite(latchPin, HIGH);
 }

if (array[klick]-1 == 2) {
    digitalWrite(latchPin, LOW);
    shiftOut(dataPin, clockPin, MSBFIRST, 91);
    digitalWrite(latchPin, HIGH);
}

if (array[klick]-1 == 3) {
    digitalWrite(latchPin, LOW);
    shiftOut(dataPin, clockPin, MSBFIRST, 79);
    digitalWrite(latchPin, HIGH);
}

if (array[klick]-1 == 4) {
    digitalWrite(latchPin, LOW);
    shiftOut(dataPin, clockPin, MSBFIRST, 102);
    digitalWrite(latchPin, HIGH);
}

if (array[klick]-1 == 5) {
    digitalWrite(latchPin, LOW);
    shiftOut(dataPin, clockPin, MSBFIRST, 109);
    digitalWrite(latchPin, HIGH);
}

if (array[klick]-1 == 6) {
    digitalWrite(latchPin, LOW);
    shiftOut(dataPin, clockPin, MSBFIRST, 125);
    digitalWrite(latchPin, HIGH);
}

if (array[klick]-1 == 7) {
    digitalWrite(latchPin, LOW);
    shiftOut(dataPin, clockPin, MSBFIRST, 7);
    digitalWrite(latchPin, HIGH);
}

if (array[klick]-1 == 8) {
    digitalWrite(latchPin, LOW);
    shiftOut(dataPin, clockPin, MSBFIRST, 127);
    digitalWrite(latchPin, HIGH);
}

if (array[klick]-1 == 9) {
    digitalWrite(latchPin, LOW);
    shiftOut(dataPin, clockPin, MSBFIRST, 111);
    digitalWrite(latchPin, HIGH);
}

  if (digitalRead(6) == LOW) {
    delay (50);
    if (digitalRead(6) == LOW) {
      klick = klick + 1;
    }
  }
//push random button

if (klick == -1){
   for (int i= 0; i< 10; i++)
 {
   int pos = random(10);
   int t = array[i];
   array[i] = array[pos];
   array[pos] = t;
 }
}
if (klick > -1 && klick < 10){
   Serial.print(klick);
   Serial.print(": ");
   Serial.println(array[klick]-1);
 }
// serial prnt optional, not need

if (klick > 10){
klick = -1;
  }
  // random part end

    if (digitalRead(5) == LOW) {
    delay (50);
    if (digitalRead(5) == LOW) {
      counter = counter + 1;
   
   
  if (counter == 1){
  digit1b = array[klick]-1;
  digitalWrite(8, HIGH);
}
  if (counter == 2){
  digit2b = array[klick]-1;
  digitalWrite(9, HIGH);
}
  if (counter == 3){
  digit3b = array[klick]-1;
  digitalWrite(10, HIGH);
}
  if (counter == 4){
  digit4b = array[klick]-1;
  digitalWrite(11, HIGH);
  delay (2000);
}
}
}
// number in button
 
if (counter == 4) {
if (digit1b == digit1a && digit2b == digit2a && digit3b == digit3a && digit4b == digit4a) {
      digitalWrite(7, HIGH);
      delay(8000);
      digitalWrite(7, LOW);
      digitalWrite(8, LOW);
      digitalWrite(9, LOW);
      digitalWrite(10, LOW);
      digitalWrite(11, LOW);
      counter = 0;
      klick = -1;
     }else {
      digitalWrite(8, LOW);
      digitalWrite(9, LOW);
      digitalWrite(10, LOW);
      digitalWrite(11, LOW);
      counter = 0;
      klick = -1;
}
}
  delay(150);

}

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Further development:
Brightness change  measurement hindrance...