SimpleKeypad library for Arduino

SimpleKeypad is an Arduino library for using matrix keypads. SimpleKeypad is based on the original Keypad library, but it is a simplified version. It does not support mutiple keypresses. It requires less memory and runs a bit faster.

This code was tested on the Arduino Uno and Nano, but it should work on any card.

Functions

SimpleKeypad() : Constructor (see the example)

getKey() : Scans the keypad every 10 ms and returns a key only one time, when you start pressing it

scan() : Scans the keypad and returns the raw output (the key currently being held down)

Example

#include <SimpleKeypad.h>

const byte nb_rows = 4;                         // four rows
const byte nb_cols = 4;                         // four columns
char key_chars[nb_rows][nb_cols] = {            // The symbols of the keys
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};
byte rowPins[nb_rows] = {9, 8, 7, 6};           // The pins where the rows are connected
byte colPins[nb_cols] = {5, 4, 3, 2};           // The pins where the columns are connected

SimpleKeypad kp1((char*)key_chars, rowPins, colPins, nb_rows, nb_cols);   // New keypad called kp1

void setup() {
  Serial.begin(9600);
  Serial.println("Press any key on the keypad and it will show up here :");
}

void loop() {
  char key = kp1.getKey();                      // The getKey function scans the keypad every 10 ms and returns a key only one time, when you start pressing it
  if (key) {                                    // If getKey returned any key
    Serial.println(key);                        // it is printed on the serial monitor
  }
}