Arduino Starter Kit, Winstar LCD shows "9" as "90".

Other Hardware Displays
1

Greetings from Kazakhstan.

I've received my Arduino Starter Kit about a week ago, and after making all projects in the book i've decided to make something on my on.

The decision as to make a simple combination lock, using 10k potentiometer and LCD. The result is in attached file. The principle is simple - until you wont enter the correct first digit and hold it for 3 seconds, you wont be able to enter the second digit and etc.

The problem that i've encountered is that when i adjust potentiometer to number 9, LCD somehow shows 9 as 90 and accepts it as correct digit. But after switch to third digit, it's shown as 9. After spinning a potentiometer, it once again show 9 as 90. The same goes to all one-digit numbers.

What could be the possible problem and it's solution?

Some additional info:

  1. Potentiometer value is mapped as (potVal, 0, 1023, 0, 99);
  2. Serial monitor shows 9 as 9
  3. Potentiometers included in starter kit are horrible. Their pins are bigger than breadboard holes, had to use pliers to adjust them =/
  4. It's 5:25 in the morning here, and i have only one solutions i came up to, whih is not using one-digit numbers. But it sucks, one-digit numbers are cool.

Also, here's the code (pretty bulky, Im a complete noob in programming).

#include <LiquidCrystal.h>;
LiquidCrystal lcd(12,11,5,4,3,2);

const int code1 = 23;
const int code2 = 9;
const int code3 = 88;
int Position = 0;
int potVal;
int currCode;
int val = 0;
int currPosition;
long prevMillis = 0;

byte p2 [8] = {
  B00000,
  B00000,
  B00000,
  B11111,
  B00000,
  B00000,
  B00000,
};
void setup (){
  lcd.begin(16,2);
  lcd.print ("Enter code");
  lcd.createChar (0, p2);
  lcd.setCursor (2,1);
  lcd.write ((byte)0);
  lcd.setCursor (5,1);
  lcd.write ((byte)0);
}
void loop (){
  if (currPosition != 3){
  lcd.setCursor (10,1);
  lcd.print ("Locked");
  }
  potVal = analogRead (A0);
  currCode = map (potVal, 0, 1023, 0, 99);

  
if (currPosition == Position){
  lcd.setCursor (0,1);
  lcd.print (currCode);
  if (currCode == code1){
    if(millis() - prevMillis > 1000){
   prevMillis = millis();
      val++;
      }
      }
      else { val = 0;
      }
      if (val>=3){
        lcd.setCursor (0,1);
        lcd.print (code1);
        currPosition = 1;
        val = 0;
}
}
if (currPosition == 1){
        lcd.setCursor (3,1);
        lcd.print (currCode);
       if (currCode == code2){
       if (millis() - prevMillis > 1000){
      prevMillis = millis();
         val++;
      }
      }
      else { val = 0;
      }
      if (val>=3){
        lcd.setCursor (3,1);
        lcd.print (code2);
        currPosition = 2; 
       val = 0; 
}
}
if (currPosition == 2){
        lcd.setCursor (6,1);
        lcd.print (currCode);
       if (currCode == code3){
       if(millis() - prevMillis > 1000){
      prevMillis = millis();
         val++;
      }
      }
      else { val = 0;
      }
      if (val>=3){
        lcd.setCursor (6,1);
        lcd.print (code3);
        val = 0;
        currPosition = 3;
}
}
if (currPosition == 3){
    lcd.setCursor (10,1);
  lcd.print ("Opened");
  }
  }

Thank you in advance, community!

Code lock.jpg

2

Change:

  lcd.setCursor (0,1);
  lcd.print (currCode);

to:

  lcd.setCursor (0,1);
  lcd.print ("  ");  // Two spaces to clear the area of screen the number will occupy
  lcd.setCursor (0,1);
  lcd.print (currCode);
3

The decision as to make a simple combination lock, using 10k potentiometer and LCD. The result is in attached file. The principle is simple - until you wont enter the correct first digit and hold it for 3 seconds, you wont be able to enter the second digit and etc.

Of course you realize that this technique makes it easier for someone to 'crack' your combination.

Wouldn't it be harder to crack if you did let them enter the second and third digits even if the earlier one(s) were incorrect. If the lock didn't open three seconds after entering the third digit they would then know that at least one of their entries was incorrect, but they wouldn't know which one was incorrect.

Also, your display might look better if you used two digits for each entry by including the leading zeroes for the low numbers. This would also remove your original problem for this type of application.

Don