This week we attach a keypad to an Arduino and show you how you can easily accept input. Then we build a combination door lock with that same keypad. For both projects we also use the serial LCD that we learned in Episode 5.
Downloads
Keypad Input
/*############################## KEYPAD INPUT ##################################
This sketch takes input from a keypad and displays the key that was
pressed on an LCD screen.
To read the keypad input that is is a 4x4 input, we are using a
library from the arduino website called Keypad. You can download this
library at: http://arduino.cc/playground/Code/Keypad
From: Mike Myers (http://mikemyers.me) @netnutmike
Let's Make It Episode 6 (http://tech-zen.tv/index.php/shows/let-s-make-it/episodes/59-sensor-fun-with-arduino-1-massive-failure-but-4-successes-let-s-make-it-episode-6)
http://tech-zen.tv
For the sample code, show notes, contact information and many more
videos, visit the show page at http://tech-zen.tv/letsmakeit
Please subscribe to our YouTube channel or our netcasts at any of
your favorite netcast / podcast outlets.
We normally record Let's Make It live on Tuesday evenings around
7pm eastern. You can watch it live by going to tech-zen.tv and clicking
the live link at the top of the page.
We also have a community setup for our viewers and listeners. You can
join the community by going to community.tech-zen.tv.
We love input on what you would like to know or if you have an idea for
a new Let's Make it episode, you can contact us via email or phone at
the show information page.
################################################################################*/
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <Keypad.h>
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] = {11,10,9,8};
byte colPins[cols] = {7,6,5,4};
Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, rows, cols);
LiquidCrystal_I2C lcd(0x3F,20,4); // set the LCD address to 0x27 for a 16 chars and 2 line display
void setup()
{
lcd.init(); // initialize the lcd
lcd.init();
// Print a message to the LCD.
lcd.backlight();
lcd.setCursor(3,0);
lcd.print("You Pressed:");
}
void loop()
{
char key = keypad.getKey();
if (int(key) != 0) {
lcd.setCursor(16,0);
lcd.print(key);
}
}Passcode Entry
/*############################## SECRET KEYCODE ##################################
This sketch takes input from a keypad for s secret code. If the code is
entered correctly it turns on a green LED to simulate access granted and
displays on the LCD access granted.
If an invalid code is entered, the red LED is lit and access denied is
displayed on the LCD.
To read the keypad input that is is a 4x4 input, we are using a
library from the arduino website called Keypad. You can download this
library at: http://arduino.cc/playground/Code/Keypad
From: Mike Myers (http://mikemyers.me) @netnutmike
Let's Make It Episode 6 (http://tech-zen.tv/index.php/shows/let-s-make-it/episodes/59-sensor-fun-with-arduino-1-massive-failure-but-4-successes-let-s-make-it-episode-6)
http://tech-zen.tv
For the sample code, show notes, contact information and many more
videos, visit the show page at http://tech-zen.tv/letsmakeit
Please subscribe to our YouTube channel or our netcasts at any of
your favorite netcast / podcast outlets.
We normally record Let's Make It live on Tuesday evenings around
7pm eastern. You can watch it live by going to tech-zen.tv and clicking
the live link at the top of the page.
We also have a community setup for our viewers and listeners. You can
join the community by going to community.tech-zen.tv.
We love input on what you would like to know or if you have an idea for
a new Let's Make it episode, you can contact us via email or phone at
the show information page.
################################################################################*/
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <Keypad.h>
//constants for LEDs
int greenLED = 12;
int redLED = 13;
//set our code
char* ourCode = "1234";
int currentPosition = 0;
//define the keypad
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] = {11,10,9,8};
byte colPins[cols] = {7,6,5,4};
Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, rows, cols);
LiquidCrystal_I2C lcd(0x3F,20,4); // set the LCD address to 0x27 for a 16 chars and 2 line display
void setup()
{
lcd.init(); // initialize the lcd
//lcd.init();
// Print a message to the LCD.
lcd.backlight();
displayCodeEntryScreen();
//setup and turn off both LEDs
pinMode(redLED, OUTPUT);
pinMode(greenLED, OUTPUT);
digitalWrite(redLED, LOW);
digitalWrite(greenLED, LOW);
}
void loop()
{
int l;
char key = keypad.getKey();
if (int(key) != 0) {
lcd.setCursor(14,3);
lcd.print(" ");
lcd.setCursor(14,3);
for (l=0; l<=currentPosition; ++l)
{
lcd.print("*");
}
if (key == ourCode[currentPosition])
{
++currentPosition;
if (currentPosition == 4)
{
unlockDoor();
currentPosition = 0;
}
} else {
invalidCode();
currentPosition = 0;
}
}
}
void invalidCode()
{
digitalWrite(redLED, HIGH);
clearScreen();
lcd.setCursor(0,0);
lcd.print("********************");
lcd.setCursor(0,1);
lcd.print("** ACCESS DENIED! **");
lcd.setCursor(0,2);
lcd.print("** INVALID CODE **");
lcd.setCursor(0,3);
lcd.print("********************");
delay(5000);
digitalWrite(redLED, LOW);
displayCodeEntryScreen();
}
void unlockDoor()
{
digitalWrite(greenLED, HIGH);
clearScreen();
lcd.setCursor(0,0);
lcd.print("********************");
lcd.setCursor(0,1);
lcd.print("** ACCESS GRANTED **");
lcd.setCursor(0,2);
lcd.print("** WELCOME!! **");
lcd.setCursor(0,3);
lcd.print("********************");
//add any code to unlock the door here
delay(5000);
digitalWrite(greenLED, LOW);
displayCodeEntryScreen();
}
void displayCodeEntryScreen()
{
clearScreen();
lcd.setCursor(0,0);
lcd.print("Let's Make It Secret");
lcd.setCursor(0,1);
lcd.print("Code Project...");
lcd.setCursor(0,2);
lcd.print("Enter Secret Code:");
}
void clearScreen()
{
lcd.setCursor(0,0);
lcd.print(" ");
lcd.setCursor(0,1);
lcd.print(" ");
lcd.setCursor(0,2);
lcd.print(" ");
lcd.setCursor(0,3);
lcd.print(" ");
}