Physical Science International Journal

The work presents the design and implementation of a Central Electronic Equipment Security Lock System - a security and access control system for used in public and private organisations as a means to restrict unauthorized access to valuable electronics equipment. The system interfaced the microcontroller (PIC16F877A) to the 16 x 2 Liquid Crystal Display (LCD) which is used to communicate/display the visual outputs to the user, multiplexed keypad (4 x 3) as input unit, three relays (30A, 12V) that serve as isolators and the buzzer-a warning device that gives an alarm when a wrong password is encoded. When the correct password is entered, the system grant access to the user and upon entry of a wrong code three times, the system gives a sound alarm via a buzzer showing that unauthorized person has tempered with the property being secured. By this, the user can also choose which equipment to grant access to (switch on) or not. The system is programmed using Assembly language and MPLAB compiler IDE to grant access to a single load or multiple loads either automatically or manually. The regulated power supply of the system showed a negligible difference of (4.9 V and 11.8 V compared to the ideal values of 5.0 V and 12.0 V respectively. Also, the system operation timing tests carried out with respect to real time showed a mean variation of 0. 005 min (0.30 sec). These errors are quite negligible hence the system is certified to be of optimal performance. The designed and implemented Central Electronic Equipment Security Lock System therefore finds suitable application in security and access control systems for use in public and private organisations as a means of restricting unauthorized access to valuable electronics equipment.