DIGITAL DOOR LOCK SYSTEM AND CONTROL METHOD FOR INFORMING WINDOWS OPENING STATUS IN CASE OF OUTING Technical Field The present invention relates, in general, to a digital door lock system and control method thereof for informing a user of open windows when the user exits and, more particularly, to a digital door lock system and control method thereof in which, in response to an exit locking signal input by an exciting user, a digital door lock attached to the door of a main gate requests and receives information about the open/shut states of windows from open/shut sensing units attached to the windows, thus outputting a stored alarm voice or flashing an alarm light when it is determined that a window is open, thereby quickly informing the user of the open window.

Background Art In recent years, to control access by unauthorized

persons to houses, stores, government buildings, office buildings, etc. , access control systems have become widely used. Conventional access control systems are configured in a variety of types: cheap locks having simple locking mechanism, expensive mechanical locks having complex mechanical locking mechanism, electronic locks having mechanical locking mechanism combined with electro- mechanical technologies, etc.

The conventional simple locking mechanism is configured to lock or unlock doors by using simple mechanical lock and key. However, the simple locking mechanism has some disadvantages that, as the number of secured places, such as houses, cars, computers and safes, requiring access control increases, the number of keys associated with locking mechanism of the places accordingly increases, thereby causing inconvenience to users carrying the bunches of keys. Another disadvantage of the conventional simple locking mechanism is that it is sometimes difficult to pick right keys from the bunches of keys. In an effort to overcome the above-mentioned

disadvantages caused by the conventional simple locking mechanism, a variety of digital door locking mechanism have been proposed and used. The conventional digital door locking mechanism comes out in several types: password input type locking mechanism in which passwords should be entered through a password input unit ; magnetic card type locking mechanism operated by magnetic cards having magnetic stripes; RF (Radio Frequency) card type locking mechanism; and IC (Integrated Circuit) card type locking mechanism.

FIG. 1 is a block diagram schematically illustrating the construction of a conventional digital door lock 100.

The conventional digital door lock 100 comprises an antenna 101, a data receiving unit 102, a remote control receiving unit 103, a keypad 104, a CPU (Central Processing Unit) 105, a motor drive unit 106, and a mortise lock 107.

The antenna 101 has an RF (Radio frequency) sensor and/or an IR (Infrared) sensor to receive input authentication data from a variety of security cards 110, such as RF cards and other mobile cards capable of

outputting RF signals and IR signals, or from a variety of mobile terminals 120 capable of performing RF communication and IR communication. The. data receiving unit 102 receives the input authentication data from the antenna 101 and transmits the input authentication data to the CPU 105.

The remote control receiving unit 103 receives a locking signal, an unlocking signal, a call signal or other signals from an RF remote controller 130, and transmits the input signals to the CPU 105. The keypad 104 outputs authentication data corresponding to pressed key buttons to the CPU 105 when a user presses designated key buttons on the keypad 104.

Upon receiving input authentication data from the data receiving unit 102, the remote control receiving unit 103 or the keypad 104, the CPU 105 compares the input authentication data with reference authentication data stored therein. When the CPU 105 determines that the input authentication data matches with the reference authentication data or when the CPU 105 receives an unlocking signal from an interphone 140, the CPU 105 sends

an unlocking control signal to the motor drive unit 106.

In response to the unlocking control signal received from the CPU 105, the motor drive unit 106 controls the mortise lock 107 into unlocking the digital door lock 100. Though not described, it is apparent that electricity is supplied to the digital door lock from an internal power supply unit or an external power source (not shown in FIG. 1).

However, the conventional digital door lock 100 illustrated in FIG. 1 provides simple functions of locking or unlocking the door to allow access only to an authorized person and to prevent an illegal entry of an unauthorized person. Thus, a user must manually lock the points of entry, for example, windows, other than the door of a main gate equipped with the digital door lock 100. In other words, the user who exits must manually lock the points of entry, for example, windows, prior to setting the digital door lock 100 of the main door to an exit locking mode'.

However, in a situation there are many windows to be locked or the user who is about to exit is very busy, the user may fail to lock the windows when exiting. In that

situation, even though illegal entry through the door of the main gate equipped with the digital door lock can be prevented without failure, an unauthorized person can enter the premises through unlocked windows. Thus, the conventional digital door locking mechanism may often lead to mental stress and a loss of property because a trespasser can enter a building through unlocked windows even if the building is provided with a digital door lock on the door of the main gate.

Disclosure of the Invention Accordingly, the present invention has been made considering the above conventional problems, and an object of the present invention is to provide a digital door lock system and control method thereof in which, in response to an exit locking signal input by a user who exits, a digital door lock attached to the door of a main gate requests and receives information about the open/shut states of windows of and from open/shut sensing units attached to the windows, thus outputting a stored alarm voice or flashing an alarm light when it is determined that a window is open, thereby quickly informing the user of the open window window.

In order to achieve the above object, in an aspect of the present invention, there is provided a digital door lock system for informing an exiting user of open windows, which controllably locks or unlocks a door of a gate in response to input data and comprises: a window monitoring unit to monitor open/shut states of one or more windows in realtime and transmit a window open/shut state signal indicative of the monitored open/shut states of the windows through wired or wireless communication in realtime; a digital door lock to receive the window open/shut state signal and check the open/shut states of the windows, in which, when an exit locking signal is transmitted from an external key input unit to the digital door lock and it is determined that at least one window is open, at least one drive signal and stored alarm voice data are output from the digital door lock; and an alarm unit connected to the digital door lock through an electric wire so that the alarm unit receives the drive signal output from the digital door lock and is driven in response to the drive signal, the alarm unit comprising a speaker to receive and amplify the alarm voice data and output an alarm voice to a surrounding area.

In another aspect of the present invention, there is provided a method of controlling a digital door lock system for informing an exiting user of open windows, the digital door lock system having a window monitoring unit to monitor open/shut states of one or more windows, a digital door lock

to receive a window open/shut state signal output from the window monitoring unit and determine whether the windows are open or shut, and an alarm unit to output an alarm voice and/or flash an alarm light under control of the digital door lock, the method comprising: (a) receiving the window open/shut state signal and checking the open/shut states of the windows in realtime ; (b) determining whether an input key value corresponds to an exit locking mode'or not when the key value is output from a key input unit; (c) checking the open/shut states of the windows using the window open/shut state signal when it is determined that the input key value corresponds to the exit locking mode'; (d) generating a speaker drive signal and transmitting the speaker drive signal to the alarm unit when it is determined that at least one window is open; and (e) reading stored alarm voice data and transmitting the alarm voice data to the alarm unit, thus outputting an alarm voice message.

Brief Description of the Drawings FIG. 1 is a block diagram schematically illustrating the construction of a conventional digital door lock; FIG. 2 is a block diagram schematically illustrating the construction of a digital door lock system for informing an exiting user of open windows, according to an

embodiment of the present invention; FIG. 3 is a block diagram schematically illustrating the structures of open/shut sensing units having different types of switches, according to embodiments of the present invention; and FIG. 4 is a flowchart of an operation process of the digital door lock system for informing an exiting user of open windows, according to an embodiment of the present invention.

Best Mode for Carrying Out the Invention Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, in which the same reference numerals are used throughout the different drawings to designate the same or similar components. In the following description, the construction and functions which are known in the related art may not be explained when it is determined that further explanation will confuse the gist of the present invention.

FIG. 2 is a block diagram schematically illustrating the construction of a digital door lock system 200 for

informing a user of locking state of windows when the user exits, according to a preferred embodiment of the present invention.

The digital door lock system 200 according to the preferred embodiment of the present invention comprises a window monitoring unit 210, a digital door lock 220 and an alarm unit 230.

The window monitoring unit 210 is provided on a window or provided at a position nearby the window for monitoring the locking state of the window, and sending a signal indicative of the sensed state of the window to the digital door lock 220. The window monitoring unit 210 includes an open/shut sensing unit 212, a signal transmitting unit 214 and a power supply unit 216.

The open/shut sensing unit 212 may include a variety of sensors or switches. Examples of sensors which can be used in the open/shut sensing unit 212 are IR (Infrared) sensors, optical sensors, magnetic sensors, ultrasonic sensors, etc. Each of the above-mentioned sensors detects the open/shut state of the window by using a variation of

physical quantities, and generates an electric signal, such as an analog signal or a digital signal corresponding to the variation.

In addition, examples of switches employed in the open/shut sensing unit 212 are mechanical switches, IR (Infrared) switches, optical switches, magnetic switches, etc. Each of the switches generates and transmits a pulse signal, such as a high signal (1) or a low signal (0), according to the open or shut state of the window.

The signal transmitted from the open/shut sensing unit 212 to the signal transmitting unit 214 is a digital signal which has a logical value of 0'when the window is shut or has a logical value of 1'when the window is open.

The construction of the open/shut sensing unit 212 according to the embodiment of the present invention may vary according to the type of sensor used (analog sensor or digital sensor) or the type of switch used (NO switch or NC switch). In other words, when the open/shut sensing unit 212 which detects the open/shut state of the window uses a digital sensor, the open/shut sensing unit 212 outputs a

high signal to the signal transmitting unit 214 when the window is open but outputs a low signal to the signal transmitting unit 214 when the window is closed.

However, when the open/shut sensing unit 212 employs an analog sensor, an analog signal output from the analog sensor is applied to an A/D converter (Analog to Digital Converter, not shown) which converts the analog signal into a digital signal and outputs the digital signal to the signal transmitting unit 214. Herein, the digital signal generated at the A/D converter is a high signal when the window is open and is a low signal when the window is closed.

The detailed construction of the open/shut sensing unit 212 is illustrated in FIG. 3.

The signal transmitting unit 214 includes a digital communication module to transmit, through wired or wireless communication, a window open/shut state signal which has been generated at the open/shut sensing unit 212 and has a digital value of 0'or 1', to the digital door lock 220.

Examples of wireless communication used for the signal communication between the window monitoring unit 210 and the digital door lock 220 according to the embodiment of the

present invention are RF (Radio Frequency) communication, IR (Infrared) communication, Bluetooth communication, etc.

Examples of wired communication used for the signal communication are serial communication, PLC (Power Line Communication), copper wire communication, etc. that support <BR> <BR> RS (Recommended Standard) -232C and RS-485. The PLC, a data communication technology based on CEBus (Consumer Electronics Bus), allows data communication using a communication device connected to a domestic plug socket, and transmits data using AC frequencies of about 50-60 Hz.

The power supply unit 214 supplies input AC power to both the open/shut sensing unit 212 and the signal transmitting unit 214.

The digital door lock 220 includes a signal receiving unit 221, a key input unit 222, a CPU (Central Processing Unit) 223, a voice data storage unit 224, a motor drive unit 225, and a mortise lock 226.

The signal receiving unit 221 receives a window open/shut state signal which has been transmitted from the signal transmitting unit 214 through wired or wireless communication and has a digital value of 0'or 1'. To perform the above-mentioned function, the signal receiving unit 221 is equipped with a communication module corresponding to a specified communication system, selected from among RF communication, IR communication, Bluetooth communication, serial communication, power line

communication and copper wire communication which is used in the signal transmitting unit 214.

The key input unit 222 is a data input unit having a plurality of key buttons to allow a user to input a key value when setting the digital door lock 220 to a locking or unlocking mode. Furthermore, when the user inputs a key value corresponding to an exit locking mode'by operating the key buttons of the key input unit 222, the key input unit 222 transmits the exit locking mode'key value to the CPU 223.

The CPU 223 reads alarm voice data stored in the voice data storage unit 235, and controls the motor drive unit 225, a speaker 232 and an alarm light 234, in response to a digital signal from the signal receiving unit 221 and a key value output from the key input unit 222. In other words, if the CPU 223 determines that the digital signal output from the signal receiving unit 221 is a high signal and a key value corresponding to the exit locking mode'has been transmitted thereto from the key input unit 222, the CPU 223 reads alarm voice data stored in the voice data storage unit 224 and outputs an alarm voice through the speaker 232.

In the meantime, if the CPU 223 determines that the digital signal output from the signal receiving unit 221 is a low signal and a key value corresponding to the exit locking mode'has been transmitted thereto from the key input unit 222, the CPU 223 outputs a drive control signal

to the motor drive unit 225, thereby activating the exit locking mode'of the digital door lock 220 by using the motor drive unit 225.

The voice data storage unit 224 stores therein at least one set of alarm voice data for informing an exiting user of unlocked windows when the user sets the digital door lock 220 to the exit locking mode'while one or more windows remains open.

In response to the drive control signal output from the CPU 223, the motor drive unit 225 drives a motor installed in the digital door lock 220. The mortise lock 226 is driven by the motor drive unit 225, and actuates its locking unit comprising a dead bolt, thus locking or unlocking the digital door lock 220.

The alarm unit 230 is mounted at a position on the digital door lock 220 or at a position adjacent to the digital door lock 220 and informs a user of open windows by sounding an alarm voice or flashing an alarm light when the user exits while any window remains open. The alarm unit 230 includes a speaker drive unit 231, the speaker 232, a flasher drive unit 233, the alarm light 234 and a flashing circuit unit 235.

The speaker drive unit 231 receives a speaker drive signal from the CPU 223 of the digital door lock 220, and drives the speaker 232. Furthermore, the speaker drive unit 231 transmits the alarm voice data to the speaker 232. The

speaker 232 amplifies the input alarm voice data, and sounds an alarm voice.

The flasher drive unit 233 receives a flasher drive signal from the CPU 223 and drives the alarm light 234. The flasher drive unit 233 operates in conjunction with the flashing circuit unit 235. The flashing circuit unit 235 switches, at predetermined time intervals, electric power supplied to the flasher drive unit 233, so that the alarm light 234 flickers periodically. The flashing circuit of the flashing circuit unit 235 is alternately turned on and off for a predetermined period when an input signal is turned on. The ON-duration and OFF-duration of the flashing circuit is adjustable manually or automatically.

FIG. 3 is a block diagram schematically illustrating the structures of open/shut sensing units 212 having different types of switches, according to embodiments of the present invention.

FIG. 3a illustrates an open/shut sensing unit 212 having both a NO (Normally Opened) switch 310 and an inverter 320. FIG. 3b illustrates an open/shut sensing unit 212 having an NC (Normally Closed) switch 330 alone.

The NO switch 310 is configured such that the switch contact point is normally opened but is closed in response to a switch pressure signal. In the embodiment of the present invention, when a window is shut and the NO switch.

310 is pressed, the switch contact point is closed so that

the NO switch 310 outputs a high signal. In the meantime, when the window is open, the switch contact point is opened so that the NO switch 310 outputs a low signal. However, in the embodiment of the present invention, the digital door lock system is configured to output the alarm voice or flash the alarm light when a user exits while a window is unlocked.

Thus, the signal output from the NO switch 310 must be inverted. To cope with the inversion, the inverter 320 is coupled to an output terminal of the NO switch 310 and inverts the signal output from the NO switch 310.

The NC switch 330 is configured such that the switch contact point is normally closed so that the NC switch 330 outputs a high signal. However, the switch contact point of the NC switch 330 is opened in response to a switch pressure signal so that the NC switch 330 outputs a low signal. Thus, in the embodiment of the present invention, when a window is open, the NC switch 330 outputs a high signal. However, when the window is shut and the NC switch 330 is pressed, the switch contact point is closed, so that the NC switch 330 outputs a low signal. Therefore, unlike the NO switch 310 of FIG. 3a, it is not necessary to couple an inverter to the NC switch 330.

FIG. 4 is a flowchart of an operation process of the digital door lock system for informing an exiting user of open windows, according to an embodiment of the present invention.

The open/shut sensing unit 212 of the window monitoring unit 210 continuously senses the open/shut states of the windows, and transmits a high signal or a low signal to the signal transmitting unit 214 (S400). The signal transmitting unit 214 receives the high signal or the low signal output from the open/shut sensing unit 212 and transmits the high signal or the low signal as a window open/shut state signal to the digital door lock 220 through wired or wireless communication (S402). Thus, the digital door lock 220 performs real-time checks of the open/shut states of the windows by using the window open/shut state signal.

A key value, which is input by an exiting user who operates the key input unit 222 provided on the digital door lock 220, is transmitted to the CPU 223. Thus, the CPU 223 checks the input key value (S404). The CPU 223 determines, through the step S404, whether the input key value is an exit locking mode'signal or not (S406).

When it is determined at S406 that the input key value is the exit locking mode'signal, the CPU 223 checks the open/shut states of the windows by using the window open/shut state signal which has been received at S402 (S408). The CPU 223 determines, through the step S408, whether at least one window is open or not (S410).

When it is determined at S410 that at least one window is open, the CPU 223 generates a speaker drive signal and

transmits the speaker drive signal to the speaker drive unit 231, thereby driving the speaker 232 (S412). Thereafter, the CPU 223 reads alarm voice data stored in the voice data storage unit 224, and transmits the alarm voice data to the speaker 232 (S414). The speaker 232 amplifies the input alarm voice data and sounds an alarm voice (S416).

When it is determined at S410 that all the windows are shut, the CPU 223 transmits a motor drive signal to the motor drive unit 225, thus driving the motor to set the digital door lock 220 to the exit locking mode' (S418).

Thus, the motor under control of the CPU 223 controls the mortise lock 226, so that a door equipped with the digital door lock 220 is locked in the exit locking mode' (S420).

In the process of FIG. 4, only the alarm voice message is used to inform an exiting user of open windows. However, the alarm function of informing an exiting user of open windows may be accomplished by use of an alarm light which is flashed periodically in the same manner as that described for FIG. 2.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. Thus, it should be understood that the embodiments disclosed in the

specification are only to illustrate, but are not to be construed as the limits of the present invention, so that the scope and spirit of the invention are not limited by the embodiments. The scope of the present invention should be construed by the accompanying claims and all the technologies equivalent to the scope of the invention as disclosed in the accompanying claims should be included in all rights reserved in the invention.

Industrial Applicability As described above, unlike a conventional digital door lock, which is configured to control access to premises only through the door of a main gate equipped with a digital door lock, so that a person can enter the premises through unlocked windows, the digital door lock system and control method thereof according to the present invention checks the open/shut states of windows when a user exits, and informs the exiting user of open windows using, for example, an alarm voice, thus allowing the user to lock the open windows without failure when exiting.

Therefore, the present invention allows the exiting user to be quickly informed of open points of entry, for

example, windows, only using a digital door lock provided on the door of a main gate, without requiring separate automatic access control devices to be provided at the points of entry. Thus, the present invention is advantageous in that it allows the user to save money and efficiently prevents a trespasser from entering the premises.