The main objective of this project is to implement an Pass word Based Door Locking System Using AT89c51 Microcontroller.
Security is a prime concern in our day-today life. Everyone wants to be as much secure as possible. An access control for doors forms a vital link in a security chain. The microcontroller based Door locker is an access control system that allows only authorized persons to access a restricted area. The system is fully controlled by the 8 bit microcontroller AT89C51 which has a 2Kbytes of ROM for the program memory. The password is stored in the EPROM so that we can change it at any time.
The system has a Keypad by which the password can be entered through it. When the entered password equals with the password stored in the memory then the Stepper motor rotate forward side so that the door is opened. If we entered a wrong password for more than three times then the Alarm is switched on. When we go inside and come back then the microcontroller will sense the person using the IR, the microcontroller will automatically open the door for you.
The default password is 1111 and you can change the password by dialing 1234, old password, and new password #button. for example if you want to change the password from the default to 4523 then dial 123411114523# after dialing you can hear a beep sound which confirm the operation goes successful.
- AT89c51 Microcontroller
- Stepper motor
- ULN2003 Motor Driver
- 5V Buzzer
- Embedded C
- KEIL Demo Version with Simulator
This project is an innovative solution to operate a machine / motor / liquid pumps for a small duration. If a machine is to be operated for ten minutes, and should be switched off after the duration, it is too difficult and many times we forget to switch it off the system after the prescribed time.
This project provides the facility of automatic switch off after the requited time duration. This is achieved by using the AT89S52 MCU. Four push-to-on switches are connected to one port of the microcontroller. These four switches are to provide four different fixed time constants.
A 16X2 LCD is connected to the microcontroller to display the status of the pump. Contrast of the LCD can adjusted by using a preset which is connected to it.
A transistor is used to drive the relay during the active time period. 5V double pole – double through relay is used to control the AC liquid pump. LED indication is provided for visual identification of the relay / load status. A switching diode is connected across the relay to neutralize the reverse EMF.
This project uses regulated 5V, 750mA power supply. Power on LED is connected for visual identification of power status. 7805 three terminal voltage regulator is used for voltage regulation. Bridge type full wave rectifier is used to rectify the ac out put of secondary of 230/18V step down transformer.