In this project, I used the 4x4 keypad to create a program that allows the user to enter a password and a green LED will light up if correct, and a red LED will light up if incorrect.

The items need are as follows:

Arduino Uno
Breadboard
Jumper Wires x 13
220 (Ohm) Resistors x2
Red and Green LED
Membrance Switch Module 4x4 Keypad

Step 1: Step 1: Add the LEDs

Place both LEDs to the breadboard
Connect the smallest lead of both LEDs to the ground rail with a Jumper Wire
Connect the 220 (Ohm) Resistor to the long lead
Now, connect the long lead of both LEDs to the Arduino using a Jumper Wire
- Red = pin 13
- Green = pin 12
Finally, connect a Jumper Wire from the ground rail on the breadboard to the GND pin on the Arduino.

Step 2: Step 2: Add the Keypad

Connect the 4x4 Keypad to the Arduino
- Start connecting the keypad with Jumper Wires to pin 9, 8, 7, 6, 5, 4, 3, and 2 on the Arduino

This step is super easy and now to move on to the code.

Step 3: Step 3: the Code

Here's the code for the program. It will turn the Green LED on and print "Access Granted" on the serial monitor when the correct password is entered. When an incorrect password is entered, the program will turn the red LED on and print "Incorrect Password" to the serial monitor.