Arduino based Automated Door Lock

Hey THERE!!

In this project we are going to build an Automated (password protected) Door lock. The classical lock and key is literally 100's of year old invention, and as we know "change is law of Nature" so its time for a change.So today we are going to build a simple and cheap Electronic door lock. The lock we are going to make is an electronic one, its brain will be Arduino Uno (Arduino nano or pro mini will also work fine), and will have a 16*2 lcd screen for display and DIY keypad for inputting password, it will be embedded with a buzzer. In this tutorial I am going to use dc hobby motor for lock mechanism. Components required to build the lock are easily avilable online as well as offline,

~ Arduino Uno 

~16*2 lcd display

~l293D IC

~DC hobby motor / Servo motor

~push switch x 18

~perf board

~1Kohm resistor x 16

~10Kohm potentiometer

~1Mohm resistor

~buzzer

~enclosure for placing the components

some wires , headers, solder and soldering iron will be enough to make automated door lock. 

Now connecting Lcd with arduino-i have made DIY shield for this display to connect Lcd more easily. We are going to use 4 data pins (namely D4,D5,D6,D7) of display for interfacing it with arduino. Making keypad-I have made my simple keypad instead of using keypad module available in market, because it uses 8 i/o pins and if we use this module. We will be lacking in I/O pins for other components.So, I decided to make own keypad module which uses only one analog pin of arduino!! we can make it easily with the help of some push buttons and resistors. working principle of this is Voltage Divider, To make automated latch I am using a regular door latch(Kundi), a dc motor, two push button ,threaded rod( i have used a bolt), a nut and some kind of epoxy to join things together( i have used M seal). Just join threaded rod with motor shaft and nut with latch handle, glue two push button on latch in such a way that whenever latch handle is in its extreme position either of push button should be pressed.connect motor with a motor driver , here I am using L293D ic for controlling Dc hobby motor. I have added a buzzer for making lock more interactive, i have attached one wire of buzzer to gnd and other to pin 10 of arduino.I have used a wooden frame for securing Lcd and keypad which I have mounted over a plastic case containing arduino, buzzer and motor driver. There is not much to say about code, I made it myself and it works fine. There are two keys through which gate can be opened. one is master key which is pre declared in code and can not be changed and other key is updatable and stored in eeprom and can be changed by pressing C key If by mistake you have entered wrong key you can erase it by pressing A key of keypad.