Abstract

The persistent rise in unauthorised entry, burglary and asset theft across residential, commercial and institutional premises has intensified demand for affordable, reliable and locally maintainable electronic security solutions. This study presents the design and implementation of a Personal Identification Number (PIN) based digital access control system for theft prevention, built around an ATmega328P microcontroller, a 4×4 matrix keypad, a 16×2 liquid crystal display, an electromechanical relay driving a solenoid lock, a piezo-buzzer and a GSM module for remote alerting. The system authenticates users by comparing an entered PIN against a value stored in non-volatile EEPROM, grants or denies access accordingly, and escalates to an audible alarm and an SMS notification after three consecutive failed attempts. The work was guided by three objectives, three research questions and three hypotheses. A mixed-method approach combined bench testing of the prototype across 500 controlled trials with a survey of 120 respondents drawn from households and small businesses. Reliability testing recorded an overall authentication success rate of 98.6%, an alarm-triggering accuracy of 97.4% and a mean unlockresponse time of 1.8 seconds. Inferential analysis showed a strong, positive and statistically significant relationship between perceived security effectiveness and willingness to adopt the system (Pearson r = 0.78, p < 0.001), while regression analysis indicated that perceived effectiveness, ease of use and affordability jointly explained 71% of the variance in adoption intention (R² = 0.71, p < 0.001). The findings confirm that a low-cost PIN-based access control system can deliver dependable theft-prevention performance and high user acceptance. The study recommends layered authentication, tamper detection and battery backup as priorities for future iterations.