Introduction: LCD Display Home Lock System

This project will act as an home lock, and the only way you can get inside the house is from pressing the correct 3 digit code. The LCD will act as a communication device to inform the individual if they have entered the correct code or not. The IR receiver will act as the device to take input from the user, and finally the step motor will unlock and "open" the house door if the correct code has been entered.


  • 16*2 LCD display
  • IR receiver
  • Step motor
  • ULN2003 driver board
  • Jumper Wires
  • Potentiometer
  • Breadboard
  • 10 K resistor

Step 1: Step 1: Connecting LCD Display

The first step you want to complete before assembling your LCD is connect the breadboard to 5V and GND.

  • Connect 1st pin to GND
  • Connect 2nd pin to power
  • Connect 3rd pin to the middle pin of the potentiometer
  • Connect 4th pin to pin 2 on the Arduino
  • Connect 5th pin to GND
  • Connect 6th pin to A4
  • Connect 11th pin to A3
  • Connect 12th pin to A2
  • Connect 13th pin to A1
  • Connect 14th pin to A0
  • Connect 15th pin to a 10 K ohm resistor which connects to power
  • Connect 16th pin to GND

Step 2: Step 2: Potentiometer

  • Connect the far right pin to Power
  • Connect far left pin to GND
  • Connect middle pin to pin 3 on the LCD

Step 3: Step 3: IR Receiver

There are 3 legs on the IR receiver. The leg on the far right is VCC (power), the leg on the far left if OUT (connect to a pin), and the middle leg is for GND.

  • Connect the VCC to the power rail on the breadboard
  • Connect the OUT pin to A2 on the Arduino
  • Connect the GND pin to the ground rail on the breadboard

Step 4: Step 4: Setup Step Motor

Follow the circuit above. Be sure to connect the the white pins into the drive module and then begin connecting the drive module pins top the Arduino pins.

Step 5: Step 5: the Code

Before you get started on the code be sure to get a TV remote and get decode the HEX codes for your remote. You would need to decode 3 numbers for this project (for the password to your 'house'). Don't forget to download the IR remote library.

To do this use this code:


void setup(){


irReceiver.enableIRIn(); }

void loop() {

if (irReceiver.decode(&result)) {


Serial.println(result.value, HEX); } }

Step 6: Step 6: Final Code

Here is the final code for this home unlock system. Be sure to change the top hex codes into the hex codes that you have received through your T.V remote. If you have any questions, don't hesitate to ask me in the comments below.