Patent Publication Number: US-9845964-B2

Title: Air conditioner having human body sensing antenna unit

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     Pursuant to 35 U.S.C. §119(a), this application claims the benefit of Korean Patent Application No. 10-2013-0070275 filed on Jun. 19, 2013, which is hereby incorporated by reference as if fully set forth herein. 
     FIELD 
     The present disclosure relates to an air conditioner, and more particularly, to an air conditioner having a human body sensing antenna unit that senses movement of human bodies or the number of human bodies located within an indoor space. 
     BACKGROUND 
     In general, an air conditioner is an apparatus which cools or heats an indoor space by performing a process of compressing, condensing, expanding, and evaporating a refrigerant. 
     Recently, as energy saving measures to address global warming have been implemented, various methods for effective energy consumption of conventional energy consumption apparatuses have been proposed. 
     As to such energy saving, methods of controlling air conditioners in which the number of human bodies or movement of human bodies located within an indoor space is sensed and temperature is controlled thereby have been proposed. 
     Conventional air conditioners are classified into two types, as detailed below, according to human body sensing methods. 
     First, a triangular method is a method of calculating the position of an object by measuring distances from pre-defined reference points. As the triangular method, there are an active badge system using infrared light, an active bat system using ultrasonic waves, and an easy living system using a vision system. 
     Next, a proximity method is a method of determining a position using proximity to a known reference point. As the proximity method, there is a smart floor system using a pressure sensor and an automatic ID system using RFID. 
     Further, human body sensing devices may be divided into a terminal based method, such as an active bat system, and a non-terminal based method using a vision sensor or a pressure sensor according to whether or not a resident possesses a terminal. 
     In case of the terminal based method using infrared light or ultrasonic waves, the position of a resident is not searched but the position of a terminal possessed by a resident is searched. Thereby, only if a resident possesses a terminal at all time in an indoor space, the position of the terminal of the resident may be recognized. 
     On the other hand, an easy living system using a vision system may cause privacy violation in home, and a smart floor system using a pressure sensor may have poor scalability and a difficulty in management. 
     As human body sensors which have been used or developed now in security, home electronics, and lighting, passive infrared sensors (PIR), which directly generate electrical signals in response to external heat sources, are employed. These conventional human body sensors are motion sensors which may sense a human body present within a sensing area only if the human body moves, and such a PIR sensor senses infrared light of 8˜12 μm emitted from a human body when the human body moves. Then, the PIR sensor converts received light energy, changed when the PIR sensor senses infrared light, into an electrical signal and may thus recognize the human body moving within a sensing range. 
     SUMMARY 
     An innovative aspect of the subject matter described in this specification may be embodied in an air conditioner that includes an outdoor unit; an indoor unit located in a building and configured to distribute cool air to a space within the building; and an antenna unit configured to sense (i) movement of human bodies within the space or (ii) presence of human bodies located in the space and determine a number of human bodies based on the sensed presence, where the antenna unit includes a housing and a plurality of antenna arrays located on an outer surface of the housing. 
     These and other embodiments can each optionally include one or more of the following features. The housing is detachably located on the indoor unit or a ceiling of the space. The indoor unit includes an indoor unit housing that defines an external appearance of the indoor unit. The indoor unit housing includes (i) a front panel that defines a frame part of a lower surface of the indoor unit, (ii) a cabinet located on the upper surface of the front panel, (iii) an indoor fan, and (iv) an indoor heat exchanger. The housing is detachably located on the front panel. The housing is configured to rotate and has a circular cross section. 
     The housing is a conical shape or a hemispherical shape. The housing is located in the space and the circular cross section of the housing decreases from a surface where the housing is located in a direction perpendicular the surface. The plurality of antenna arrays is located on the housing in the circumferential direction of the housing and is configured to sense movement of human bodies or the presence of human bodies in the space. Each of the antenna arrays comprises a plurality of antenna patterns arranged in a line. Each of the plurality of antenna arrays is separated a respective distance along the outer surface of the housing. Each distance decreases in a downward direction perpendicular a surface where the housing is located. 
     The space is divided into a plurality of detection zones, wherein a number of the plurality of antenna arrays corresponds to a number of the plurality of detection zones. The antenna unit further includes (i) a transceiver configured to receive radio signals from the plurality of antenna arrays or transmit radio signals to the plurality of antenna arrays and (ii) a switch that is configured to connect the plurality of antenna arrays to the transceiver. The switch sequentially connects the plurality of antenna arrays to the transceiver and sequentially disconnects the plurality of antenna arrays from the transceiver in a designated direction. The antenna array is an IR-UWB antenna array. 
     Another innovative aspect of the subject matter described in this specification may be embodied in an air conditioner that includes an outdoor unit; an indoor unit located in a building and configured to distribute cool air to a space within the building; and an antenna unit located in the space, where the antenna unit includes (i) a housing, (ii) a plurality of antenna arrays located around a circumference of the housing and configured to sense (i) movement of human bodies within the space or (ii) presence of human bodies in space and determine a number of human bodies based on the sensed presence. 
     These and other embodiments can each optionally include one or more of the following features. The space is divided into a plurality of detection zones, wherein a number of the plurality of antenna arrays corresponds to a number of the plurality of detection zones. The housing is detachably located on the indoor unit or a ceiling of the space. 
     Another innovative aspect of the subject matter described in this specification may be embodied in an air conditioner that includes an outdoor unit; an indoor unit located in a building and configured to distribute cool air to a space within the building; and an antenna unit located in the space, where the antenna unit includes a housing; a plurality of antenna arrays configured to sense (i) movement of human bodies within the space or (ii) presence of human bodies in the space; a processor configured to determine a number of human bodies based on the sensed presence; a transceiver configured to receive radio signals from the plurality of antenna arrays or transmit radio signals to the plurality of antenna array; and a switch configured to connect the plurality of antenna arrays to the transceiver, where the switch sequentially connects the plurality of antenna arrays to the transceiver and sequentially disconnects the plurality of antenna arrays from the transceiver in a designated direction. 
     These and other embodiments can each optionally include one or more of the following features. The transceiver and the switch are located on the housing of the antenna unit. The transceiver and the switch are located on a printed circuit board (PCB) and the switch is an RF switching element located on the PCB. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view illustrating an example indoor unit of an air conditioner. 
         FIG. 2  is a perspective view illustrating an example outdoor unit of an air conditioner. 
         FIG. 3  is a block diagram schematically illustrating a configuration of an example indoor unit and an example outdoor unit. 
         FIGS. 4-5  are perspective views illustrating external appearances of example antenna units. 
         FIG. 6  is a view illustrating an example antenna unit installed on a ceiling. 
         FIG. 7  is a view schematically illustrating an example indoor unit divided into a plurality of zones and an example antenna unit. 
         FIG. 8  is a block diagram schematically illustrating a configuration of an example antenna unit. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a perspective view illustrating an example indoor unit  10  of an air conditioner.  FIG. 2  is a perspective view illustrating an example outdoor unit  20  of the air conditioner.  FIG. 3  is a block diagram schematically illustrating a configuration of an example indoor unit  10  and an example outdoor unit  20 . 
     The air conditioner may include an indoor unit  10  and an outdoor unit  20 . Further, the air conditioner may include a four-way valve  240 . 
     With reference to  FIGS. 1 and 3 , the indoor unit  10  may include an indoor heat exchanger  150  and an indoor fan  160 . The indoor unit  10  further includes an indoor unit housing  11 , and the indoor heat exchanger  150  and the indoor fan  160  are accommodated in the indoor unit housing  11 . 
     The indoor heat exchanger  150  may function as an evaporator during cooling operation and function as a condenser during heating operation. The indoor heat exchanger  150  is connected to an outdoor heat exchanger  270  of the outdoor unit  20  through a circulation path  230  along which a refrigerant circulates. 
     In some implementations, the indoor unit  10  may be installed such that the upper part of the indoor unit  10  is inserted into a ceiling and the lower surface of the indoor unit  10  is exposed downward from the ceiling to the outside. 
     With reference to  FIG. 1 , the indoor unit housing  11  forming the external appearance of the indoor unit  10  may include a front panel  110  forming the frame part of the lower surface of the indoor unit  10 . Further, the indoor unit housing  11  may include a suction grill  120  installed at the center of the front panel  110  so as to cause indoor air to be introduced into the indoor unit  10 . Further, the indoor unit housing  11  may include a cabinet  130  forming the upper portion of the indoor unit  10  and accommodating a plurality of components therein. The cabinet  130  is provided on the upper surface of the front panel  110 . Further, the indoor unit housing  11  may include a base  140  closing the upper surface of the cabinet  130  and causing the indoor unit  10  to be mounted within a ceiling. 
     A tetragonal hole is formed through the center of the front panel  110 , the suction grill  120  is mounted within the hole, and rectangular discharge holes  112  are formed at the edge of the front panel  110 . The discharge holes  112  discharges air, heat-exchanged in the indoor unit  10 , again to an indoor space. The discharge holes  112  having the same shape may be formed through the edge of the front panel  110 . 
     A louver  114  forcibly determining the flow direction of air discharged to the indoor space through the discharge hole  112  is formed at the discharge hole  112 . The louver  114  has a rectangular plate shape corresponding to the shape and size of the discharge hole  112 , is connected to a motor (not shown) generating rotary force, and is rotated, thus forcibly determining the flow direction of air. Therefore, air discharged to the indoor space through the discharge hole  112  is blown to a region distant from the discharge hole  112  and thus, the indoor unit  10  maximizes air conditioning effects. 
     The suction grill  120  having an approximately tetragonal plate shape is mounted at the center of the front panel  110 . As described above, the suction grill  120  sucks indoor air to the inside of the indoor unit  10 . Therefore, a plurality of suction holes  122  extended in the horizontal direction is vertically formed through the center of the suction grill  120 . Here, reference numeral  116  represents a refrigerant sensor detecting leaked refrigerant. 
     The indoor heat exchanger  150  and the indoor fan  160  may be installed within the cabinet  130 . 
     A plurality of indoor units  10  may be provided and the plural indoor units  10  may be respectively disposed within plural indoor spaces. The outdoor unit  20  may be disposed at an outdoor space. 
     With reference to  FIG. 3 , the outdoor unit  20  may include a compressor  220 , an outdoor heat exchanger  270 , an outdoor expansion valve  250 , and an outdoor fan  260 . Further, the outdoor unit  20  may include an outdoor unit housing  21  (with reference to  FIG. 2 ) and the compressor  220 , the outdoor heat exchanger  270 , the outdoor expansion valve  250 , and the outdoor fan  260  are accommodated within the outdoor unit housing  21 . The outdoor heat exchanger  270  may function as a condenser during cooling operation and function as an evaporator during heating operation. 
     The compressor  220  compresses introduced refrigerant in a low-temperature and low-pressure state into refrigerant in a high-temperature and high-pressure state. Various structures may be applied to the compressor  220 , and an inverter-type compressor may be employed as the compressor  220 . 
     With reference to  FIG. 2 , the outdoor unit housing  21  may include a front panel  211  closing the indoor space of the outdoor unit  20  at the front and forming the front surface of the outdoor unit housing  21 . Further, the outdoor unit housing  21  may include side grills  213  guiding introduction of outdoor air at the left and right sides of the outdoor unit housing  21 . Further, the outdoor unit housing  21  may include a rear grill guiding introduction of external air from the rear to the inside of the outdoor unit housing  21 . Further, the outdoor unit housing  21  may include a base  219  supporting a plurality of components. Further, the outdoor unit housing  21  may include a upper panel  215  guiding discharge of air, heat-exchanged in the outdoor unit  20 , in the upward direction. 
     A pair of ventilation holes  214  may be formed at the center of the upper panel  215  so as to discharge air, heat-exchanged in the outdoor unit  20 , to the outside of the outdoor unit  20 . 
     A shroud  212  having a cylindrical shape is mounted at the border of the upper surface of the ventilation hole  214 , and the number of the shrouds  212  corresponds to the number of the ventilation holes  214 . The shroud  212  guides the flow direction of air discharged to the outside of the outdoor unit  20  through the ventilation hole  214 . An outdoor fan  260  may be provided in the shroud  212 . 
     The four-way valve  240  adjusts the circulation path  230  of the refrigerant discharged from the compressor  220 . That is, the four-way valve  240  is a flow path change valve for conversion between cooling and heating, and guides the refrigerant compressed by the compressor  220  to the outdoor heat exchanger  270  during cooling operation and guides the refrigerant compressed by the compressor  220  to the indoor heat exchanger  150  during heating operation. 
     Further, the air conditioner may include a controller controlling at least one of temperature, air direction, air volume, and air velocity according to the number of human bodies or movement of human bodies sensed by a human body sensing antenna unit  300 , which will be described later. 
       FIGS. 4-5  are perspective views illustrating external appearances of example antenna units  300   a  and  300   b .  FIG. 6  is a view illustrating an example antenna unit  300  installed on a ceiling.  FIG. 7  is a view schematically illustrating an example indoor unit  10  divided into a plurality of zones and an example antenna unit  300 .  FIG. 8  is a block diagram schematically illustrating a configuration of an example antenna unit  300 . 
     In some implementations, the air conditioner may include the human body sensing antenna unit  300  sensing movement of human bodies or the number of human bodies located within an air conditioning space in which the indoor unit  10  is installed. 
     With reference to  FIGS. 4 and 8 , the antenna unit  300   a  may include a plurality of antenna arrays  310 . Further, the antenna unit  300   a  may include a housing  320  provided with the outer surface on which the plurality of antenna arrays  310  is installed. Further, the antenna unit  300   a  may include a transceiver  370  transmitting a radio signal to the antenna arrays  310  and receiving radio signals from the antenna arrays  310 . Further, the antenna unit  300   a  may include a switch  350  selectively connecting the plurality of antenna arrays  310  and the transceiver  370 . Further, the antenna unit  300   a  may include a signal processor  390  receiving reflected radio signals received by the antenna arrays  310  from the transceiver  370 , processing the reflected radio signals, and thus judging whether or not human bodies move within the indoor space and the number of human bodies located in the indoor space. 
     The transceiver  370  may be replaced with a transmitter transmitting radio signals and a receiver receiving radio signals. 
     The antenna unit  300   a  may be an ultra wide band (UWB) antenna unit. More particularly, the antenna unit  310  may be an impulse radio UWB (IR-UWB) antenna unit. 
     IR-UWB is a low-velocity position-based network technology using a UWB pulse and provides functions of distance estimation and position estimation forming the basis of Ubiquitous Environment. IR-UWB provides an error range of one meter or less in distance estimation. Based on wireless communication, IR-UWB uses an ultra wide band of 3.1 GHz˜10.6 GHz as a frequency band and assures a system dynamic range within thirty meters. 
     The frequency band used by IR-UWB may be divided into three bands, i.e., a sub-GHz band, a low-band, and a high-band. Sixteen channels are assigned to the three bands. The sixteen channels may be divided into channels including channels 0, 3 and 9, and other channels. In some implementations, one channel is implemented. IR-UWB may be applied to position estimation in a stopped and/or low-velocity moving state. 
     Although the human body sensing antenna unit  300   a  is installed in an indoor space in which the indoor unit  10  is installed, the position of the human body sensing antenna unit  300   a  is not limited thereto. However, in order to cover the entirety of the indoor space without a dead zone, the antenna unit  30  may be installed on the ceiling C of the indoor space in which the indoor unit  10  is installed, i.e., an air conditioning space (with reference to  FIG. 6 ). 
     The antenna unit  300  may be installed on the ceiling, i.e., the ceiling surface, of the indoor space or on the above-described indoor unit  10 . Here, the antenna unit  300  may be installed on the indoor unit housing  11  of the indoor unit  10  and, in some implementations, installed on the front panel  110  of the indoor unit housing  11 . 
     With reference to  FIG. 1 , the antenna unit  300  may be installed at the edge of the front panel  110 . If the front panel  110  has a rectangular shape, the antenna unit  300  may be installed at a corner A of the front panel  110 . In some implementations, the antenna unit  300  may be installed at the corner A located between neighboring discharge holes  112 . 
     Further, the antenna unit  300  may be provided so as to be detachably installed on the ceiling or the indoor unit  10 . Therefore, the antenna unit  300  may be may be installed selectively at a position of the indoor space in which the indoor unit  10  is installed, where there may not be an obstacle and the antenna unit  300  effectively covers the entirety of the indoor space. 
     With reference to  FIGS. 4 and 6 , the housing  320   a  has a designated space formed therein and the antenna arrays  310  are installed on the outer surface of the housing  320   a . Although the shape of the housing  320   a  may be variously modified, the housing  320   a  may be a rotating body having a circular horizontal section. In some implementations, the housing  320   a  may have a conical shape. 
     If the housing  320   a  has a conical shape, the conical housing  320   a  is installed such that the apex of the conical housing  320   a  faces downward. That is, the conical housing  320   a  is installed such that the apex or generating line of the conical housing  320   a  faces the indoor space downward. In more detail, the housing  320   a  is installed such that the horizontal sectional area of the housing  320   a  decreases in a downward direction perpendicular to the ceiling surface. Here, the lower surface of the conical housing  320   a  is closely adhered to the ceiling surface C. As described above, at least one of the transceiver  370  and the switch  350  is installed within the housing  320   a  and, more particularly, both the transceiver  370  and the switch  350  may be installed within the housing  320   a . The lower surface of the housing  320   a  may be opened so as to achieve communication between the transceiver  370  and switch  350  and the signal processor  390 . 
     Plural antenna patterns  310   a  are arranged in a line, thus forming one antenna array  310 . The antenna patterns  310   a  are attached to the outer surface of the housing  320   a.    
     The plurality of antenna arrays  310  is installed along the outer surface of the housing  320   a . Here, the plural antenna arrays  310  may be separated from each other by a designated interval on the outer surface of the housing  320   a.    
     Further, the antenna arrays  310 , each of which has a structure in which the plural antenna patterns  310   a  are arranged in a line, may be installed so as to face the lower surface of the housing  320   a  from the generating line of the housing  320   a  (or in the reverse direction). Therefore, the plural antenna arrays  310  are separated from each other by a designated interval in the circumferential direction of the outer surface of the housing  320   a.    
     The interval between the plural antenna arrays  310  may decrease in the downward direction perpendicular to the surface C on which the housing  320   a  is installed. That is, the interval d n  between the plural antenna arrays  310  decreases in a direction from the installation surface C to the lower end of the housing  320   a.    
     One antenna array  310  senses movement of human bodies or the number of human bodies located within the corresponding one of zones divided from the indoor space. 
     Further, with reference to  FIG. 5 , the housing  320   b  may have a hemispherical shape. If the housing  320   b  has a hemispherical shape, plural antenna arrays  310  may be installed so as to face the lower surface of the housing  320   b  and be separated from each other by a designated interval in the circumferential direction of the outer circumferential surface of the housing  320   b.    
     In some implementations, the housing  320   b  may have various other shapes, such as a sphere, a cone, a cylinder, and a polypyramid. 
     With reference to  FIG. 7 , the number of the antenna arrays  310  corresponds to the number of zones divided from the indoor space. For example, if the indoor space in which the indoor unit  10  is installed is divided into 8 zones, 8 antenna arrays  310  may be provided on the housing  320 . 
     Radio waves emitted by the antenna arrays  310  are transmitted to the corresponding zones of the indoor space and are reflected by obstacles (human bodies or fixed objects). The reflected radio waves are received by the antenna arrays  310  sensing the corresponding zones. 
     With reference to  FIG. 8 , the transceiver  370  may function to generate a radio signal and to transmit the radio signal to the antenna array  310  or to receive radio signals from the antenna array  310 . The transceiver  370  may be located within the housing  320 . 
     The transceiver  370  transmits the radio signals received from the antenna array  310  to the signal processor  390 . The signal processor  390  may sense movement of human bodies or the number of human bodies in the corresponding zones using the received radio signals. Further, the controller controls at least one of indoor temperature, air direction, air volume and air velocity according to movement of human bodies or the number of human bodies sensed by the signal processor  390 . 
     In order to transmit the radio signal generated by the transceiver  370  to the plurality of antenna arrays  310 , the antenna unit  300  includes the switch  350 . The switch  350  may be located between the antenna arrays  310  and the transceiver  370 . 
     The switch  350  selectively connects the plurality of antenna arrays  310  to the transceiver  370 . 
     If the number of the plural antenna arrays  310  is n, the switch  350  sequentially connects the n antenna arrays  310  to the transceiver  370 . 
     If the first antenna array  311  emits radio waves, the switch  350  connects the first antenna array  311  to the transceiver  370  and, if the second antenna array  312  emits radio waves, the switch  350  connects the second antenna array  312  to the transceiver  370 . After the switch  350  sequentially connects the n th  antenna array to the transceiver  370  in such a manner, the switch  350  connects the first antenna array  311  to the transceiver  370  again. 
     The n antenna arrays  310  sense movement of human bodies or the number of human bodies located in the n corresponding zones divided from the indoor space. 
     The switch  350  may be an RF switching element having a MEMS structure. The switch  350  in an element type may be provided on a PCB. Here, the switch  350  may be mounted on the PCB. Further, both the transceiver  370  and the switch  350  in an element type may be mounted on a PCB. 
     With reference to  FIGS. 7 and 8 , operation of the human body sensing antenna unit  300  of the air conditioner will be described. 
     The plural antenna arrays  310  are disposed along the outer circumferential surface of the housing  320  in the circumferential direction. Each of the plural antenna arrays  310  senses movement of human bodies or the number of human bodies located in each of zones (zone  1  to zone  8 ) divided from the indoor space. 
     The switch  350  sequentially connects the plural antenna arrays  310  to the transceiver  370  and releases connection of the plural antenna arrays  310  to the transceiver  370 . Here, the switch  350  connects the adjacent antenna arrays  310  installed on the housing  320  to the transceiver  370  in a designated direction. 
     After the switch  350  releases connection of a specific antenna array  310  to the transceiver  370 , the switch  350  connects another antenna array  310 , sensing a zone adjacent to the zone sensed by the specific antenna array  310 , to the transceiver  370 . That is, the switch  350  connects the antenna array  310  sensing the zone  1  to the transceiver  370  and then connects the antenna array  310  sensing the zone  2  adjacent to the zone  1  to the transceiver  370 . Here, the switch  350  may connect the antenna arrays  310  to the transceiver  370  in the counterclockwise direction or the clockwise direction. 
     In more detail, if the first antenna array  311  senses movement of human bodies or the number of human bodies within a corresponding zone, the switch  350  connects the first antenna array  311  to the transceiver  370 . 
     The transceiver  370  transmits a radio signal, which will be emitted through the antenna arrays  310 , to the first antenna array  311 . 
     Then, the first antenna array  311  emits radio waves to the zone  1 . The radio waves emitted by the first antenna array  311  are reflected by an obstacle in the zone  1  and are received again by the first antenna array  311 . 
     The radio signal received by the first antenna array  311  is transmitted to the transceiver  370  through the switch  350 . The transceiver  370  transmits the radio signal received from the first antenna array  311  to the signal processor  390 . 
     When the transceiver  370  transmits the radio signal to the signal processor  390 , the switch  350  releases connection of the first antenna array  311  to the transceiver  370 . Thereafter, the switch  350  connects the second antenna array  312  to the transceiver  370 . The subsequent process is the same as the above-described process performed by the first antenna array  311  and a detailed description thereof will thus be omitted. 
     By repeating such a process, the switch  350  releases connection of the n th  antenna array  310  to the transceiver  370 , and then connects the first antenna array  311  to the transceiver  370  again. 
     Here, the first antenna array  311  and the second antenna array  312  are located adjacent to each other. That is, the first antenna array  311  and the second antenna array  312  are antenna arrays respectively sensing two adjacent zones divided from the indoor space. 
     In some implementations, the described air conditioner may sense movement of human bodies or the number of human bodies located in an indoor space instead of a conventional air conditioner sensing human bodies through an IR-UWB antenna using infrared light. 
     The human body sensing antenna unit of the air conditioner may be detachably installed on the ceiling or the indoor unit and thus, the installation position of the human body sensing antenna unit may be changed according to sizes or shapes of an indoor space. 
     The indoor space in which the air conditioner is installed may have various shapes according to building structures. If the human body sensing antenna unit is fixed to the indoor unit, the antenna unit may not be disposed at a proper position so as to correspond to various indoor spaces. In some implementations, the antenna unit is detachably provided and may thus be installed at a position to cover the corresponding indoor space. 
     Further, in the conventional air conditioner, if human bodies are sensed using an antenna, one antenna does not sense all directions of an indoor space and thus needs to be rotated by a motor. In some implementations, a switch sequentially connecting a plurality of antenna arrays to a transceiver is provided, a motor to rotate the antenna unit may not required, and thus motor manufacturing costs may be reduced and air conditioner manufacturing costs may be reduced. 
     In some implementations, an air conditioner having a human body sensing unit may sense movement of human bodies or the number of human bodies located within an indoor space. 
     In some implementations, the human body sensing antenna unit may be detachably installed on a ceiling or an indoor unit and thus, the installation position of the human body sensing antenna unit may be changed according to sizes or shapes of the indoor unit. 
     In some implementations, the air conditioner is provided with a switch sequentially connecting a plurality of antenna arrays to a transceiver and may not require a motor to rotate the antenna unit, and may thus reduce motor manufacturing costs.