Apparatus and method for locating missing article

An apparatus for locating a missing article, comprising:

• a signal sensor including a piezoelectric element for detecting an external signal and generating a location confirm sound, a signal buffer for buffering the signal detected by the piezoelectric element, and an analog/digital converter for converting an analog signal from the signal buffer to a digital signal;
• a signal processor including an integrator for integrating a signal sensed by the signal sensor, a signal delay for delaying an output signal from the integrator, an inverter for interrupting an output signal from the signal delay when it is inputted for less than a predetermined time and inverting a phase of the output signal from the signal delay when it is inputted for the predetermined time or more, and a compulsory signal interrupter for compulsorily interrupting an output signal from the inverter when the output signal from the inverter lasts for more than the predetermined time;
• and
• a main controller including a memory for storing a password, and a plurality of timers for counting respective periods of a wake-up signal and one or more finding signals, silent times, and one or more finding password wait times, respectively.

A method for locating a missing article using a missing article locating apparatus, comprising:

• a) if an input signal lasts for a wake-up hardware delay time determined by a circuit configuration of the missing article locating apparatus in a standby mode where standby power is supplied to the apparatus, calling a wake-up password processing routine and supplying main power to the apparatus, and if the input signal further lasts for a wake-up program delay time, determining the input signal to be a valid wake-up signal, determining whether a signal is inputted for a first silent time, and starting time counting for confirmation of a finding signal if no signal is inputted for the first silent time;
• b) calling a finding password processing routine if the finding signal is inputted at a predetermined timing during the time counting at the step a), determining whether a signal is inputted for a second silent time if a pre-registered finding password is set to two or more, and determining whether the pre-registered finding password is satisfied if no signal is inputted for the second silent time;
• and
• c) determining whether a signal is inputted for a last silent time if the pre-registered finding password is satisfied, calling a location confirm sound generating routine to generate a location confirm sound, if no signal is inputted for the last silent time, and stopping the generation of the location confirm sound if a signal is sensed in the middle of generating the location confirm sound, a signal is inputted through a function input unit, or the number of times that the location confirm sound is generated expires.

An input method of a function input unit of a missing article locating apparatus, comprising:

• a) if a function key of the function input unit is operated in a standby mode where standby power is supplied to the missing article locating apparatus, supplying main power to the apparatus and determining whether the function key has been pressed for a predetermined first time or more, and if it is determined that the function key has not been pressed for the first time or more, recognizing the pressing of the function key as an abnormal key operation, initializing each port and then turning the main power off;
• b) if the function key has been pressed for the first time or more, recognizing the pressing of the function key as a normal key operation, generating a beep and flickering a light emitting diode, so as to inform a user that the function key has normally been operated;
• c) determining whether the function key has been pressed for a predetermined second time or more after the step b), and if it is determined that the function key has not been pressed for the second time or more, recognizing that the user uses the missing article locating apparatus as an illuminator and turning the light emitting diode on to perform an illumination function;
• d) if the function key is again inputted or a certain time elapses after the light emitting diode is turned on, turning the light emitting diode off to end the illumination function, initializing each port and then turning the main power off;
• and
• e) if it is determined at the step c) that the function key has been pressed for the second time or more, generating the beep and flickering the light emitting diode, so as to inform the user that he/she has to set a finding password, and calling a finding password input routine to set the finding password.