An application of microcomputer design is given. A microprocessor based system is used to automate the entry logging procedure for a teaching laboratory. The system is used to control entry point security and maintain a laboratory logbook for each entry/exit transaction. A barcode scanner interfaced to the microprocessor identifies users by reading their university ID cards. A permanent record of each entry/exit is made on a magnetic cassette tape. A software package which runs on the university's mainframe computer is used to analyze the entry/exit information. / M. S.