Security prime concern in our day to day life. Everyone wants to be as much as secure to be possible.an access control systems forms a vital link in a security
chain.The microcontroller based digital lock presented here is an access control that allow only authorized person to access a restricted area.This system is based
suitable for corporate offices,atms,home security. As a simple example ,to lock our mobile phones keypads, a security code of at least 4 digits must be entered.The
system comprises a small electronic unit with a mobile keypad which is outside the entry door to control a solenoid-operated lock with help of D.C. motor. when an
authorized person enter predetermined password via the hand held mobile keypad from some other place ,the stepper motor is operated for a limited time to unlatch
the solenoid operated lock so the door can be open. At the end of preset delay, the stepper is operated in the reverse direction and door gets lock again .A DTMF
decoder CM8870C which decode the keypad signals and these signal are given to the micro controller .A buzzer is provide for audio acknowledgement of the key
impression. Whenever a key is press on the numeric keypad, the system acknowledges the impression by a short beep sound . The keil cross compiler is used to edit, compile and debug this program and the program used is embedded C.
good projects for final year.