Home security is one of the most critical concerns in daily life. Traditional home security typically depends heavily on locks; however, it is inconvenient for people to carry numerous keys simply to open doors. In this paper a novel human–machine interface was integrated in a home-security system. The developed system applies the action of knocking as the input interface to unlock a door without using keys. First, the unlock areas on the door are set. When a user knocks on the door, the system obtains knocking information from six vibration sensors in the door. A pattern-recognition algorithm subsequently identifies the knocking pattern of the user, including the knocking areas and the knocking sequence. The k-nearest neighbor algorithm was employed to construct the identification classifiers. According to the simulation results, the accuracy of identifying the correct knocking areas was between 90% and 93%. In addition, the performance of the proposed home-security system was satisfactory in field trials.
ICIC express letters. Part B, Applications 6(10), pp.2877-2882