DESIGN AND CONSTRUCTION OF A REMOTE CODED SECURITY SYSTEM

Abstract

Remote coded access security systems are used to restrict people from gaining access to a place, equipment, items or database depending on the electronic logic applied to the switching terminal as described here. To open the system a 3 digit password stored in the group of latches (74374) must be entered in the correct sequence by first resetting the system. The comparator (7845) unit of the system compares the entered code with that already stored in the latches; access is granted if the password corresponds together by switching an electrical device. The password can also be entered via a remote control which transmits pulses in form of infrared rays and op-amp (LM 393) consisting of the photo diode which receives the transmitted rays, this is enabled by using a 7490 decade counter to count the pulses. This project h as a built in alarm system that consists of t wo monostable 555 timer, the alarm system signals an intruder, if the codes are entered wrongly three times. This system finds application everywhere, including banks, military database systems and equipments, conglomerates, schools, etc.