Numpad mit LCD-I2C 16x2 Display

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Hello guys,

how do I get it so that when I press Number "1" on the numpad, one sentence comes up on the display. Likewise, how do I make the sentence disappear automatically after 20 seconds?

That's how far I have come now:

#include <Keypad.h>
#include <LiquidCrystal_I2C.h>

const int ROW_NUM    = 4; // four rows
const int COLUMN_NUM = 4; // four columns

char keys[ROW_NUM][COLUMN_NUM] = {
  {'D','#','0','*'},
  {'C','9','8','7'},
  {'B','6','5','4'},
  {'A','3','2','1'}
};

byte pin_rows[ROW_NUM] = {6, 7, 8, 9};      // connect to the row pinouts of the keypad
byte pin_column[COLUMN_NUM] = {2, 3, 4, 5}; // connect to the column pinouts of the keypad

Keypad keypad = Keypad(makeKeymap(keys), pin_rows, pin_column, ROW_NUM, COLUMN_NUM );
LiquidCrystal_I2C lcd(0x27, 16, 2); // I2C address 0x27, 16 column and 2 rows

int cursorColumn = 0;

void setup(){
  lcd.init(); // initialize the lcd
  lcd.backlight();
}

void loop(){
  char key = keypad.getKey();

  if (key) {
    lcd.setCursor(cursorColumn, 0); // move cursor to   (cursorColumn, 0)
    lcd.print(key);                 // print key at (cursorColumn, 0)

    cursorColumn++;                 // move cursor to next position
    if(cursorColumn == 16) {        // if reaching limit, clear LCD
      lcd.clear();
      cursorColumn = 0;
    }
  }
}

A more advanced task would be:

If I make a typo, I press "A" on the numpad and the sentence gets deleted.

I hope you understand the problem and could help me.

Cheers! :smiley: