Functioning of Digital Code Lock with LCD using 8051 Microcontroller The digital code lock system with LCD using 8051 microcontrollers is a password-based system. This project can be used as a security checking system to stop access to a room only for unauthorized persons with the password. So this project can be named with a wide range of names such as a digital combination lock, a digital security code lock, a password security system, an electronic code lock, a digital code lock. People name this type of a security system with various names, although all of them mean to make a password-based security system with a different microcontroller with some extra features like automatic door open or lock, GSM-based SMS alert, sound alarm, etc. Digital Code Lock with LCD using 8051 Microcontroller In our day to day life, Security is a major problem, and digital code locks have become a significant part of the security system. There are several types of technologies available for security purpose, like PIR Based, RFID based, Laser-based, and biometric-based, etc. Even now, there are Digital code locks which can be worked using smartphones also based on IoT (Internet of Things). In this proposed system, we have discussed a simple Digital code lock using LCD and 8051 Microcontroller, which can only be not closed by a predefined code, if we enter the incorrect code, the system generates the buzzer. Digital Code Lock Block Diagram This project can be built with 8051 series microcontroller, keypad, buzzer, LCD. Here the microcontroller controls the entire process like entering the password from the keypad, compares the entered password with the predefined password, drives the buzzer and send the status to the display. Digital Code Lock Block Diagram Keypad Module In this project, we have interfaced 4X4 keypad to the 8051 microcontroller using multiplexing techniques for entering the digital code in the system. Here this 4×4 keypad has 16 keys. If we want to use 16 keys on the keypad, then we need 16-pin for connecting the microcontroller, but in this technique, we require to use only 8-pins for interfacing 16-keys. So that it can interface the keypad module. Please refer this link to know more about matrix keypad and its interfacing Keypad Module LCD The LCD screen is an electronic display module, it can be used in a wide range of applications. The basic module of the LCD is 16×2 LCD display and is very frequently used in various electronic circuits and well as devices. Please refer this link to know more about LCD Display construction and its working LCD AT89C51 Microcontroller The AT89C51 is an 8-bit microcontroller which belongs to Atmel’s 8051 families. AT89S51 Microcontroller Working of the Project The proposed system uses a matrix keypad and an LCD as an input and output devices. A 4-digit predefined password requires to be specified the person. This password is saved in the system. While opening, if the given password from matrix keypad matchs with the saved password, then the lock gets opened and a note is displayed on the LCD. Also, an o/p pin is made high to be used for further purposes. As the program runs, the string ‘Enter Password’ is exhibited on the LCD. The keypad is checked for the entered digits one by one. Each time, row & column of the key pushed is noticed and a * is shown on LCD parallel to the entered number. After the password is entered, the consumer is provoked to ‘verify Password’ and yet again the key is taken through the LCD. If the given passwords do not equal, a note is displayed to specify ‘Wrong Password’; or else the user is provoked to open the device. To open, a person needs to ‘Enter Password’ through a keypad. Again the keypad is checked for the entered digits and equivalent digits are recognized. The passkey is exhibited as ‘****’ on the LCD display. After the password is entered, they are contrasted with the predetermined password. If all the digits equal to a set password, LCD exhibits ‘Lock Open’ and the output pin of the lock go high. If the code is wrong, ‘Wrong Password’ is sent to be shown on the LCD. The system gets protected if more than three tries are made with an incorrect password to unlock the digital code lock. The system desires to be rearranged in such a case. Thus, this is all about the functioning of digital code lock with LCD using 8051 microcontrollers. We hope you have understood the project well. If you have any queries. Please feel free to ask, and if you would like to implement similar projects like keypad based projects, please comment in the comments section. 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