Microcontroller Based Digital Code Lock

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 AT89C2051 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 relay gets on and 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 Laser light, the microcontroller will automatically open the door for you.

INTRODUCTION…………………..4

PROJECT DESCRIPTION…………...…5

BLOCK DIAGRAM……………………...…5

BLOCK DIAGRAM EXPLANATION……………………5

CIRCUIT DIAGRAM…………………..11

MAIN CIRCUIT DIAGRAM……………………………11

POWER SUPPLY……………………………………..12

CIRCUIT EXPLANATION………………………………...12

FLOW CHART.…… ………………………13

PROGRAM…………………………...14

COMPONENTS DETAILS…………….…22

RESISTOR……………………………………..22

CAPACITOR…………………………….….22

TRANSISTOR………………….…...23

DIODE…………………………………………23

INTEGRATED CIRCUITS…………………….……...24

CONCLUSION……………………………….30

APPLICATIONS………………………………30

FUTURE ENHANCEMENT……………..30

REFERENCES……………………..……31