The Basic requirement of security can be achieved by designing electrical or mechanical locks that are designed with one or a few keys, but for locking a big area many locks are required. Basically traditional locks are heavy and are not protective as they can be broken down easily by using some tools. Electronic locking systems are preferable over mechanical locks, to resolve the security problems that are associated with the mechanical locks.
Nowadays every device’s operation is based on digital technology. For instance, token-based digital identity devices, Fort-token mobile and digital-based door lock systems for auto door opening or closing are all based on digital technology. These locking systems are used to control the movement of door and are functional without requiring a key to lock or unlock the door. These locking systems are controlled by a keypad and are installed at the side hedge of the door.
1. Password Based Door Locking System
In this project, a keypad is attached to the door for opening and closing operations of the door. After entering the code, if that code matches with the predefined one, then the door will unlock for a limited period of time. After prolonging the unlocking for a fixed period of time, the relay reenergizes and the door gets locked again. If anyone enters a wrong code in an attempt to open the door and attempts thrice, then this system immediately switches an alarm or a buzzer.
The operation of this system can be described by the above block diagram, which consists of blocks as keypad, a buzzer, an LCD, a Motor Driver and a stepper motor. The Keypad is an input device that helps to enter a code to open the door. This block gives the entered code signals to the microcontroller. The buzzer and LCD are the final indicating devices for displaying the information and alarming. The Stepper motor moves the door: opens and closes the door, and the motor driver drives this motor by receiving control signals from the microcontroller.
The microcontroller used in this project is from 8051 family, and it is programmed with the Keil software. When a person enters a password by using various keys in the keypad ranging from 0 to 9 including ‘Enter’ and ‘Escape’ keys, then the microcontroller immediately reads the data and compares it with the stored data.
If this data matches, the microcontroller sends display information to the LCD display as ‘Code is authenticated’. Furthermore, the microcontroller sends the command signals to the motor-driver IC to rotate the motor in a particular direction such that the door opens. After sometime, the spring system with a specified time delay closes its relay, and then the door starts closing and slowly comes to its normal closed position.
If the person attempting to open the door enters a wrong password, then the microcontroller switches the alarm for further course of action. In this way, a simple door-lock system can be implemented with the use of a microcontroller.
2. ATmega Based Garage Door Opening
This is an advanced door opening system compared to the above system. This system uses Android technology for opening and closing operations. Hence, users can use their Android mobiles for door operations instead of using a keypad.
This system uses an ATmega series controller, a Bluetooth modem, an Android mobile, a buzzer, a relay driver, relays and lamps (instead of motors) for achieving remote controlled operations of the door.
This project is designed to unlock a garage door with an Android device by entering a single password in an Android application. An Android OS-based device, such as a mobile or tablet, is connected to this system through a Bluetooth device. The Bluetooth device is attached to the ATmega microcontroller, which is programmed with a particular password for opening and closing the garage door by its owner. An android application with a Graphical User Interface based touch screen operation of any mobile allows any user to enter this particular password in it.
Before sending this information to the microcontroller, the Bluetooth of the phone is paired to the Bluetooth modem attached to the control device. After entering the password in the Android mobile, it sends that data to the microcontroller via its Bluetooth. With the stored password in the microcontroller, it compares and sends the control signals to the relay driver only if the two passwords match.
Then, the relay performs mechanical operations to open and close the door through the motor, but in this project – the motor is replaced with the lamp for a better indication purpose. In this project, a lamp is used in place of a motor for visualization purpose. If the entered password is wrong, then the system generates a buzzer. After opening the door, the motor automatically closes the door with a predefined time setting on microcontroller for the reverse rotation of the motor.
3. Movement Sensing Automatic Door Operating System
This system doesn’t use any input devices like a keypad or Android commands as with the above two systems, but automatically senses the motion of humans to automatically open and close a door by using a passive infrared sensor.
The above two projects come under the security systems’ category, but this project implements an effort needed to pull or push the doors. This Passive-Infrared-Sensor based simple door lock system reduces or the PIR detects the presence of human beings when they reach in its proximity. Pyro-electric sensors in the PIR introduce changes in their temperature due to infrared radiation from humans.
For opening and closing the door, a person is always required in some places like shopping malls, theaters and hotels and it is a boring job. So this system automatically detects the person approaching towards the door by sensing the energy from their body. When a person approaches within the range of the sensor, it sends logical commands to the microcontroller. This controller further sends the control signals to the motor driver IC so that the motor is rotated in appropriate directions.
The door automatically returns to its original position, i.e., closed position – after a fixed time delay. This system also provides protection against the locked rotor system by placing limit switches to the motor which are given to the microcontroller as an interrupt signals.
These are the basic projects based on the doorlock system. We hope that you have got a better understanding of this concept with the above three examples. Please share your views on this article in the comments section below, and for further help to implement these projects, you can contact us.
- Door lock system by homedepot