help with keypad reading...

Projects General Guidance
1

Hey guys, having a problem with my project. i have a keypad from seeedstudio. (12 key, 13 pin individual pins for each key).
i got the project working with a really long if statement but im trying to clean up my code and possibly get the keypad readings using a couple of arrays to read which button is pressed...
problem is that i can't get it to read which button and my lcd screen only shows "#" constantly.

my code is as follows:

#include <LiquidCrystal.h>

LiquidCrystal lcd(12, 11, 10, 9, 8, 7);

String button;

String Keys[12] = {"1","2","3",
                 "4","5","6",
                 "7","8","9",
                 "0","*","#"};
int Pins[12] ={A3,1,5,
               A2,0,4,
               A1,A5,3,
               A4,A0,2};

void setup() {
  
  lcd.begin(16,2);

  pinMode(A0, INPUT_PULLUP);
  pinMode(A1, INPUT_PULLUP);
  pinMode(A2, INPUT_PULLUP);
  pinMode(A3, INPUT_PULLUP);
  pinMode(A4, INPUT_PULLUP);
  pinMode(A5, INPUT_PULLUP);
  pinMode(0, INPUT_PULLUP);
  pinMode(1, INPUT_PULLUP);
  pinMode(2, INPUT_PULLUP);
  pinMode(3, INPUT_PULLUP);
  pinMode(4, INPUT_PULLUP);
  pinMode(5, INPUT_PULLUP);
}

void loop() {
  delay(1000);
  lcd.setCursor(0,0);
  
  lcd.print(GetKey());
  
}

String GetKey(){  
  for(int i=0; i<13; i++){
    if(digitalRead(Pins[i] == LOW)){
      button = Keys[i];
    }
  }
  return button;  
}
2

Are you using an Arduino Uno ? Could you remove every use of the String object ?

char button;

char Keys[12] = {'1','2','3',
                 '4','5','6',
                 '7','8','9',
                 '0','*','#'};

The pinMode() can be set in a loop as well.

  #define numKEYS 12

  for( int i=0; i<numKEYS; i++)
    pinMode( [Pins[i], INPUT_PULLUP);

When you read the keys, the array index is from [ 0 ] up to [ 11 ]. You use also [ 12 ] which is beyond the array.
You could stop the loop as soon as a button is pressed (it would be better to return every button that is simultaneously pressed).
If no button is pressed you have to clear the button.

  for(int i=0; i<numKEYS; i++){      // numKEYS is 12
    if(digitalRead(Pins[i] == LOW)){
      button = Keys[i];
      break;                                       // key pressed, don't check the others.
    }
  }
  button = 0;                                    // make button a space or zero or something.

Instead of ascii code or strings for the buttons, I would use normal integer values for the buttons. When the button with "3" is pressed, I would return integer value 3. To make them readable on the display, they might have to be converted to text.

3

http://playground.arduino.cc/Main/KeypadTutorial

4

thanks for you help. few stupid mistakes and your fix made it work perfectly.