Arduino - Keypad - LCD
Hardware Required
Or you can buy the following sensor kits:
1 | × | DIYables Sensor Kit (30 sensors/displays) | |
1 | × | DIYables Sensor Kit (18 sensors/displays) |
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About Keypad and LCD
If you do not know about keypad and LCD (pinout, how it works, how to program ...), learn about them in the following tutorials:
Wiring Diagram
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Arduino Code
/*
* Created by ArduinoGetStarted.com
*
* This example code is in the public domain
*
* Tutorial page: https://arduinogetstarted.com/tutorials/arduino-keypad-lcd
*/
#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] = {
{'1','2','3', 'A'},
{'4','5','6', 'B'},
{'7','8','9', 'C'},
{'*','0','#', 'D'}
};
byte pin_rows[ROW_NUM] = {9, 8, 7, 6}; // connect to the row pinouts of the keypad
byte pin_column[COLUMN_NUM] = {5, 4, 3, 2}; // 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;
}
}
}
※ NOTE THAT:
The I2C address of LCD can vary according to the manufacturers. In the code, we used 0x27 that is specified by DIYables manufacturer
Quick Steps
- Connect Arduino to PC via USB cable
- Open Arduino IDE, select the right board and port
- Navigate to the Libraries icon on the left bar of the Arduino IDE.
- Search “keypad”, then find the keypad library by Mark Stanley, Alexander Brevig
- Click Install button to install keypad library.
- Search “LiquidCrystal I2C”, then find the LiquidCrystal_I2C library by Frank de Brabander
- Click Install button to install LiquidCrystal_I2C library.
- Copy the above code and open with Arduino IDE
- Click Upload button on Arduino IDE to upload code to Arduino
- Press some keys on keypad
- See the result in LCD
If LCD displays nothing, see Troubleshooting on LCD I2C
Code Explanation
Read the line-by-line explanation in comment lines of source code!
Video Tutorial
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