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
Manual operation of school bell / college bell creates lot of disturbances caused by human errors. If the bell operator forgets to ring the bell for a specific period, or delayed to ring the bell, it creates disturbances for entire the institution. All the classes on that day will be completely disturbed. This problem is more present if the bell operator is on leave. Automatic Periodic College Bell is the only solution to avoid all these problems.
The Project AT89S8252 Microcontroller Based Automatic Periodic College Bell with RTC DS1307 Interfacing is an interesting project which uses AT89S8252 microcontroller as its brain. This project is very useful in schools, colleges and educational / academic institutions for automation of periodic class bell. This bell rings only at preprogrammed timings. As the DS1307 Real Time Clock chip is used, entire the calendar can be programmed into the microcontroller. User can program the bell to ring the bell from morning to evening and not to ring in after school hours and on Sundays and Second Saturdays. Micro Switches is provided for entering the required timings. This switches made this project user friendly. 16X2 LCD display is provided to display the alarm times and current time. DS1307 is interfaced to the microcontroller for real timing performance. A 3V battery can be connected to DS1307 to avoid time disturbances caused by power failures.
AT89S8252 has inbuilt flash EPROM. Data stored remains in the memory even after power failure, as the memory ensures reading of the latest saved settings by the micro controller. It can retain data for more than ten years. This project uses regulated 5V, 500mA power supply. Unregulated 12V DC is used for relay. 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 230/12V step down transformer.
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.