Abstract
There have been developed in authentication systems for information using biometric information approaches such as fingerprint, face, and iris. In general, a door-lock system is operated by touching keypads, which remains fingerprints on the keypads. Such door-lock systems do not protect personal information from others due to the exposure of fingerprints to keypads. In this paper, we propose the new door-lock system that does not leave fingerprints on the keypads. Without touching keypad the system works because the system accepts authentication information by using illuminance sensor and LED. The experiment shows that the implemented door-lock system works well under any circumstance.