ISSUES WITH THE KEYPAD LIBRARY

Projects Programming
1

I'm working on a small project with a keypad that I am trying to interface with the Keypad.h library. Everything is working fine, but when I push the A, B, C, or D button it gives me the characters from the first column instead of the 4th. I'm not sure what's going wrong in my code. Does someone have any ideas?

#include <LiquidCrystal.h>
#include <Keypad.h>
#include <Password.h>
#include <EEPROM.h>

// Define pins used for the LCD.
LiquidCrystal lcd(A0, A1, A2, A3, A4, A5);

// Define keypad parameters.
const byte ROWS = 4;
const byte COLS = 4;

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

byte rowPins[ROWS] = {10, 11, 12, 13};
byte colPins[COLS] = {6, 7, 8, 9};

Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);



void setup() {
  Serial.begin(9600);
  lcd.begin(16, 2);
  lcd.clear();

}

void loop() {

  char key = keypad.getKey();

  if (key) {
    Serial.println(key);
  }


  
}
2

What do you get when you press keys in the first column ?

3

I'm not sure what's going wrong in my code. Does someone have any ideas?

Nothing. You have the keypad connected incorrectly.

4

(deleted)

5

What do you get when you press keys in the first column ?

When the first column (1, 4, 7, *) is pressed it gives the correct characters. Same with the second and third column. When the 4th column is pressed it gives the characters as if it were the 1st column.

I took the keypad out to test the row and column wires by shorting them (like the keypad would) and they all work properly. Except pin 9 seems to be a duplicate of pin 6.

6

jamescb82:
I took the keypad out to test the row and column wires by shorting them (like the keypad would) and they all work properly. Except pin 9 seems to be a duplicate of pin 6.

Very strange. Have you checked to see if 9 and 6 are shorted together? The sketch looks fine so I think it is a hardware problem.

7

Very strange. Have you checked to see if 9 and 6 are shorted together? The sketch looks fine so I think it is a hardware problem.

It really is weird. I moved the pin 9 wire around to tidy a few things up and made sure nothing was shorting, I even checked with a multimeter. Still a no go.

8

So I made column 4 use pin 2 instead of pin 9. That seems to have solved the problem, though I have no idea why which is really going to bother me :confused: