Abstract: An occupant detection system and method are provided for detecting an occupant seated in a vehicle seat. An electrode is arranged in a seat proximate to an expected location of an occupant for sensing an occupant proximate thereto. The electrode may be integrated with a seat heater. Control circuitry controls the seat heater. A signal generator is coupled to the electrode and configured output to the electrode a plurality of signals at a plurality of frequencies. Occupant detection circuitry detects voltages responsive to the plurality of signals at the plurality of frequencies and detects a state of occupancy based on the detected voltages. An LC circuit coupled to the electrode and the control circuitry suppresses capacitance generated by the control circuitry.

Abstract: A bed includes a frame, a controller coupled to the frame, and a patient position detection system coupled to the frame and coupled to the controller. The patient position detection system has at least three modes of operation of varying sensitivities for determining whether a person supported on the frame has moved by a sufficient amount to activate an alarm.

Abstract: A seat has a seat frame and a seat cushion supported by the seat frame. The seat cushion has an upper surface that supports a user and a lower surface defining a cavity. The seat cushion moves between an at rest condition in which no operator is seated on the seat, and a deflected condition in which the seat cushion is deflected with respect to the frame in response to an operator seated on the seat. A switch is mounted to the frame and opens and closes an electrical circuit in response to an actuating force. A switch actuator is mounted to the seat cushion lower surface in the cavity and moves between a non-actuating position when the seat is at rest and an actuating position when the seat is deflected. The switch actuator delivers the actuating force as the switch actuator is moved toward the actuating position.

Abstract: To allow more reliable detection of occupancy of a seat by a person, the invention includes a detection device for detecting occupancy of a seat, in particular of a vehicle seat or motor vehicle seat, comprising at least one elongate light guide having at least one elongate core element and at least one elongate sheath at a distance from the core element. The light guide is deformable by mechanical actuation means in at least one direction running perpendicular to the longitudinal axis of the light guide by the deformation brought about by the seat being occupied causes the light to exit from the light guide on the side opposite the mechanical means.

Abstract: A system including a first electrode, a second electrode, a first circuit and a second circuit. The second electrode is capacitively coupled to the first electrode. The first circuit is configured to receive data via a network and transmit a signal via the first electrode based on the data. The second circuit is configured to receive data via the network and receive a current that corresponds to the signal via the second electrode based on the data.

Abstract: A child car seat for a land vehicle comprises a support for supporting at least a part of a body of a child, the support being positionable on a vehicle seat of the land vehicle and a restraint for holding the body in position relative to the support. A data processing unit forms when in operational mode and connected to an in-vehicle data communication network in the land vehicle, a child car seat network node in the in-vehicle data communication network. The seat includes a first network connector for establishing, in cooperation with a matching second network connector, a data communication connection between the child car seat network node and the in-vehicle data communication network. The child car seat has a signal carrier connecting the data processing unit to the first network connector.

Abstract: A seat occupant determining apparatus includes a first load detecting sensor at a right of a seat, a second load detecting sensor at a left of the seat, a third load detecting sensor at a front or a rear of the first and second load detecting sensors, in order to detect a part of the load, respectively, a right-left sum value calculating portion calculating a right-left sum value, a threshold changing portion for changing an occupant determining threshold on the basis of the load value of the third load detecting sensor, and an occupant determining portion determining an occupant of the seat to be an adult when the right-left sum value is equal to or more than the occupant determining threshold and determining an occupant of the seat to be a child in a child seat when the right-left sum value is less than the occupant determining threshold.

Abstract: A main electrode is located in a vehicle seat. A guard electrode is located between a grounded vehicle body and the main electrode. A detection unit selectively applies an alternating voltage signal to the main electrode and the guard electrode, sets the main electrode and the guard electrode to be in an open state or a grounded state, detects an electric current of one of the main electrode and the guard electrode, converts the selected electric current into a voltage value, and detects an overcurrent in the main electrode and the guard electrode. A control unit determines the main electrode and the guard electrode to be an open failure, a power supply short failure, a grounded failure, or a short failure with the guard electrode, according to one or a combination of the voltage value and detection or non-detection of an overcurrent.

Abstract: A starting device of an occupant protective system includes an angular velocity or acceleration sensor 11 for detecting the behavior of a vehicle, processing sections 131 and 132 for performing two or more computations using different subtrahends on a physical quantity based on the output from the sensor 11, a comparing section 133 for comparing absolute values of outputs from the processing sections 131 and 132, a selecting section 134 for selecting the output value of the processing sections 131 and 132 with the minimum absolute value, and a decision section 135 for making a decision as to the necessity for starting the occupant protective system in accordance with the output value selected.

Abstract: Device for vehicle seat occupancy detection, wherein a base frame which can be adjusted in the height direction of a vehicle seat and which is composed of at least two scissors arms which are connected to one another is arranged between a seat part of the vehicle seat and a vehicle body part, the device comprising a first detector which is attached to at least one of the scissors arms and which, when the vehicle seat is occupied by a minimum weight, detects a predefinable height setting of the scissors arm which is lower than a maximum possible height setting, and at least one spring which is fixed to at least one of the scissors arms and the predefinable pretensioned spring force of which corresponds at most to the downward-acting weight force due to the minimum weight and counteracts the latter.

Abstract: A system and method for providing enhanced weight alert notification during automated patient management is presented. A plurality of weight measurements in an automated patient environment from a weight monitoring device for a patient during an observation period is remotely obtained. A raw baseline weight for the patient is determined based on a function of the weight measurements. Irregularities in the weight measurements are identified. The raw baseline weight is processed into a baseline weight by application of a correction coefficient to the irregularities. Weight remotely measured in the automated patient environment for the patient on a substantially regular basis is obtained. Changes in the weight are identified by periodic comparison to the baseline weight. An alert notification is generated in response to the change in weight.

Abstract: A capacitive passenger detector includes: a capacitive sensor having main, sub and guard electrodes; a sensor characteristic measurement unit for applying an alternating voltage signal to each electrode and for converting a current in each electrode to a voltage; and a controller. The controller defines a current in the guard electrode as a reference current when voltages of the main and guard electrodes have a same potential. The controller defines a current flowing direction of the guard electrode to be negative when the voltage of the main electrode is higher than the guard electrode. The controller defines the current flowing direction of the guard electrode to be positive when the voltage of the main electrode is lower than the guard electrode. The controller corrects the voltage of the main electrode based on the current of the guard electrode so that a corrected voltage is set to be a passenger determination data.

Abstract: A passenger detection system includes a satellite sensor circuit; and a master determination unit. The satellite sensor circuit includes an antenna electrode which is provided in at least one of a seating face or a back face of a seat; and an electric field generation unit which generates an electric field around the antenna electrode, and generates a current signal based on the electric field. The master determination unit includes a current detection unit which detects a variation of the current signal; and a control unit which determines a sitting situation of a passenger by comparing signal data with threshold data, the signal data being related to a current signal which flows based on the electric field which is obtained from the current detection unit and which is generated at the antenna electrode, the threshold data being related to the sitting situation of the passenger. The satellite sensor circuit and the master determination unit are connected via a power supply line and a ground line.

Abstract: A seat occupancy display system which includes a seat occupancy sensor array with individual sensors. Each sensor is configured to detect the weight bearing thereon and to output an occupancy signal. Individual sensors can be configured to provide a location identification thereof. An interface circuit communicates the occupancy signals to a central processor which is configured to create a data file representative of the seat occupancies in the seating arena. A display coupled to the central processor is configured to display either a list of occupied seats and/or a map of the seats with an indication of which seats are not occupied. Also, orders for refreshments or other items can be ordered at each seat and the orders can be transmitted to attendants for real time payment and delivery.

Abstract: A bed includes a frame, a controller coupled to the frame, and a patient position detection system coupled to the frame and coupled to the controller. The patient position detection system has at least three modes of operation of varying sensitivities for determining whether a person supported on the frame has moved by a sufficient amount to activate an alarm.

Abstract: In or for a vehicle, an arrangement for measuring weight of an occupant of a seat connected to a floor of the vehicle via a slide mechanism, the floor, in part, defining a passenger compartment of the vehicle. A support structure extends between the slide mechanism and the seat. A force sensing device is coupled to the support structure and configured for measuring force in the support structure indicative of weight applied by the occupant to the seat. The weight may be used for component control.

Abstract: The Child Seat Safety System provides drivers (common vehicles) with an alarm and monitoring system for the attachment of safety harnesses and temperature readings for respective child seat occupants within the car. The monitoring component details the attached “status” of said harnesses through indicator lights on the main operator dashboard along with on the system device. Alarm features automatically warn either the driver or surrounding bystanders or emergency personnel of alarm situation including temperature variances, harness disengagement, accident or unattended occupant warnings. The Child Seat Safety System can reduce the risk of small children being injured due to unattached seat belts during accident, braking or collision, and can reduce exposure to unhealthy temperatures either during driving or from extended lengths of time being unattended in a car.

Abstract: A wheelchair alarm system and method for preventing falls for patients at risk by recognizing the gesture of a patient attempting to stand. The wheelchair alarm system uses an array of proximity sensors and pressure sensors to create a map of the patient's sitting position, and then uses gesture recognition algorithms to determine when a patient is attempting to stand up. The wheelchair alarm system responds with light and voice alarms that can encourage the patient to remain seated and/or to make use of the system's integrated nurse-call function. The wheelchair alarm system can be seamlessly integrated into existing hospital WiFi networks, sending messages to the nurse call system as well as providing the patient's location.

Abstract: A capacitor seat sensor includes a cushion pad for a vehicle seat, protective panels installed on an upper surface of the cushion pad, including upper, intermediate and lower sheets, and extending a predetermined distance beyond a front end of the cushion pad, conductive panels including a sensor antenna panel and a sensor guard panel which is respectively interposed between the upper and intermediate sheets of the protective panels and between the intermediate and lower sheets of the protective panels to detect the presence of an occupant on the cushion pad, and a fastener for fastening front end portions of the protective panels onto a lower end of the cushion pad so as to prevent the conductive panels from wrinkling.

Abstract: A safety belt warning system for vehicles comprises a sensor mat for the detection of a force acting on its surface, which includes, for the formation of two electrical capacitors, two dielectric layers which are located one above the other in sandwich fashion and arranged in each case between electrically conductive coats, and which have different compressibility at least in the direction of loading due to force, so that the capacitances of the two capacitors vary differently with a load on the sensor mat.

Abstract: The invention is related to capacitive detection systems and methods. In one embodiment, a capacitive detection system comprises a first transmitter electrode and a first receiver electrode disposed in a first seat and configured to form a first capacitor, and a second transmitter electrode disposed in a second seat and configured with the first receiver electrode to form a second capacitor.

Abstract: A vehicle system for communicating with a child seat is provided with a receiver configured for receiving a seat sensor signal from a child seat controller. A controller is configured for communicating with the receiver for analyzing the seat sensor signal and comparing the seat sensor signal to pre-existing guidelines to determine a status message. A user interface is configured for communicating with the controller for displaying the status message. The child seat is provided with a plurality of seat sensors for measuring different adjustable features of the seat including; a harness sensor for measuring a tension within a harness; a buckle switch for measuring a connection of a buckle; and a level sensor for measuring an inclination of a seat sub-assembly. The seat controller is provided for receiving measurement signals from the seat sensors and transmitting the seat sensor signal.

Abstract: A weight based occupant detection device that includes a weight sensing device installed in a vehicle seat in a manner effective to sense weight on a seating surface. The weight sensing device is configured to output a weight signal indicative of an occupant weight of a seat occupant residing on the vehicle seat. The occupant detection device also includes a seat orientation angle sensing device that is configured to output an orientation angle signal indicative of a seat orientation angle. The occupant detection device may also include an accelerometer for sensing vertical acceleration of the vehicle seat, and a seat backrest angle device for measuring the angle of the seat backrest. The occupant detection device compensates a signal from the weight sensing device for errors caused by seat orientation, seat vertical acceleration and seat backrest angle.

Abstract: A system and methodology utilizing seat sensors and an electronic card system that monitors the location of children on a bus as well as preventing children from being left behind, is herein disclosed. As the child enters the bus, the child would insert a personalized identification card, thereby recording the child's seat location and presence. Upon exiting, the child again inserts the identification card and following a prescribed time interval, a warning light and alarm would be activated if the seat remains occupied, thus alerting the bus driver to check the seat location. Every bus seat would have an integral weight sensor electrically connected to a main control panel. The system provides the bus driver, or assigned chaperone, a pushbutton selection array corresponding to each seat assignment.

Abstract: A portable child safety seat system has three lightweight, easily transferable modular components. The system utilizes one or more pressure sensor switches configured to be placed under the cushion of a vehicle's infant seat or cushions of multiple infant seats to detect the presence of a child in that seat. Electrical lines connect the pressure sensor switch to an interface unit which contains a back-up electrical power source, i.e. a rechargeable battery. The interface unit is in turn connected by electrical lines to a controller component which has a plug section for receiving electricity and a display section to indicate the presence of the child in the infant seat. When a child is in the infant seat and the vehicle's engine is running, the pressure sensing switch is closed and electricity is directed to light the display section of the controller. When the engine is not running, electricity is directed from the back-up battery to light the display section.

Abstract: In accordance with one aspect of the present invention, an alarm assembly for a wheel chair is disclosed. A pair of mounting brackets is combined to the frame underneath the seat of the wheel chair. A removable and extendable switch-bar selectively combines to the mounting brackets. The switch-bar is adjustable in length to accommodate chairs of various widths and selectively positionable on the mounting brackets to change the distance between the seat and switch. The switch on the switch-bar senses the presence of a patient and in response to the absence of a patient communicates an alarm signal to the alarm.

Abstract: A sheet switch (142) has a bottom layer (144) and a top layer (160). First and second conductors (148, 162) located on the bottom layer (144) form two separate conductive paths, with a voltage potential applied to the conductors (148, 162). The top layer (160) includes a ground conductor (172). Spacers (178) are positioned between the top and bottom layers (160, 144). When forces are externally applied, the spacers (178) collapse and the ground conductor (172) contacts the first and second conductors (148, 162), and establishes a conductive path therebetween.

Abstract: The invention relates to a seat occupancy sensor (10) comprising at least two switch elements (12, 14) which can be activated by pressure. Said elements can be associated with the surface of a seat and are arranged at a certain distance from each other in such a manner that a first switch element (12) is associated with a first area of the seat and a second switch element (14) is associated with a second area of the seat. According to the invention, the first and second switch elements (12, 14) are connected to each other in such a manner that a logical AND-linkage is produced. The first and second switch elements are, for example, serially connected in a particularly simple embodiment of the invention.

Abstract: In a vehicle safety system with a vehicle steering wheel, which has a steering wheel rim, and with at least one capacitive sensor which detects an alteration to an electric or electromagnetic field, the sensor is arranged in or on the steering wheel rim.

Abstract: A circuit and method for providing an improved bed pad, seatbelt or floor mat sensor monitoring system with the ability to detect a connection failure between the monitoring module and the target sensor by monitoring the connection for loss of data being transmitted or returned (looped back) by the sensor.

Abstract: A warning system for notifying another person when a child is left in a child safety seat. The system recognizes a child in a child safety seat by either a pressure pad or a secured child seat lap belt. The system is activated by the release of the driver's seat belt. Should a child remain in the seat when the driver's seat belt is disengaged, the system alarms notifying the driver of such. The alarm would include a calm audio output such as a lullaby, a song, or a story. The system can be integrated into the OEM features to provide an alert escalation process using a local alert, a vehicle alert, a wireless alert and ultimately a 911 alert.

Abstract: Method for controlling output of a classification algorithm which classifies an occupant of a seat in a vehicle in which a bladder or other type of weight sensor is arranged in a bottom cushion of the seat, data relating to the pressure exerted by the occupant on the bottom cushion is obtained from the weight sensor, the occupant is initially classified, a current classification is output using data from the weight sensor, the occupant is periodically re-classified using data from the weight sensor, and a classification change is allowed only upon obtaining evidence of a new classification which is greater than evidence of the current classification. The classification change may be enabled by determining a substantially consecutive period of time when the re-classification is unchanged and different from the current classification, and enabling the classification change upon when the consecutive period of time is greater than a threshold.

Abstract: A sun protection system for a transportation vehicle has plurality of LCD zones laminated into one or more glazings of the vehicle. An occupant sensor detects an expanse of at least one occupant in the vehicle. A navigation system determines a vehicle location, a date and time value, and a heading. External and internal temperature sensors sense outside and inside temperatures. A controller generates respective drive signals for the respective LCD zones in a manual mode and in an automatic mode. The controller compares a temperature difference between the outside temperature and the inside temperature to a temperature threshold. The respective drive signals provide substantially zero attenuation if the temperature difference is less than the temperature threshold while in the automatic mode.

Abstract: A child restraint warning system configured to be secured to a child seat/carrier having a base, a seat detachably connected to the base, where the child seat/carrier includes a harness configured to be releasably secured with a latch. When the seat is secured on the base a seat position sensor sends a signal to a control unit positioned on the back of the seat. The control unit is switched into an active status for detecting an unlocked condition of the harness latch. A first series of audible warning signals is produced by the control unit if the latch remains unlocked for a pre-determined period of time. If the latch continues to be in an unlocked condition after the first series of warning signals the control unit generates a second series of signals, which can be spoken messages pre-programmed by the user.

Abstract: An occupant detection system for a vehicle includes an antenna arrangement of a capacitance-based occupant detection device in particular provided beneath the seat surface of a vehicle seat for the generation of a first occupation signal in the event of occupation of the vehicle seat by a person based on a radiation of predetermined minimum strength starting from the antenna arrangement and passing through the person, based on at least one switch arrangement of a weight-based occupant detection device which is provided beneath the seat surface of the vehicle seat and can be actuated in dependence on the pressure acting on it in order to generate a second occupation signal in the event of occupation of the vehicle seat by a person, in particular an adult, as well as a controller that generates an occupation detection signal in the event that both the first occupation signal of the capacitance-based occupant detection device and the second occupation signal of the weight-based occupant detection device are pres

Abstract: A vehicle occupant classification system categorizes vehicle occupants into various classes such as adult, child, infant, etc. to provide variable control for a vehicle restraint system such as an airbag. The classification system utilizes sensors that are installed in various locations in the vehicle. The sensors are used to generate a three-dimensional profile for the vehicle occupant. Various factors can affect the accuracy of this three-dimensional profile. Fuzzy logic is used to reduce some of the inaccuracies by providing multiple decision levels for various stages of the classification. Inaccuracies are also caused by sensors shifting within the system from their original position. This condition creates offset and the system evaluates this offset and generates a correction factor to provide a more accurate three-dimensional profile.

Abstract: A movement monitor includes a sensor pad for sensing when a weight is placed on the sensor pad and when the weight is removed from the sensor pad. A sleeve encloses the sensor pad. A control flap is formed in the sleeve for enclosing an alarm circuit coupled to the sensor pad.

Abstract: A system and method for classifying a vehicle occupant is disclosed. A base is installed in each of leg frames of a seat of a vehicle. A cover is installed above the base to be spaced apart from the base. Two weight sensors are installed between the base and the cover to support the cover, and configured to measure a load transmitted to the cover by the weight of a vehicle occupant sitting in the seat. A control unit receives load values measured by the weight sensors, and determines whether the vehicle occupant sitting in the seat is an adult or a child based on the received load values. A shock absorption member is interposed between the weight sensors and the base. A stopper is interposed between the base and the cover in order to limit a downward movement range of the cover in a case of overload.

Abstract: The present invention relates to a method determining the morphology of the occupant of an automotive car, characterized in that it comprises the steps of collecting (200) the outputs of a plurality of capacitive sensors (100) provided on a seat, determining for each capacitive sensors (100) a first value representative of the distance (di) separating a target (10) from the sensor (100) and a second value (Sdi) representative of the surface of the sensor (100) covered by the target (10), applying (210) to the second values (Sdi) representative of the surface of the sensor (100) covered by the target (10) a respective weighting (Wi) based on the corresponding first value (di) representative of the distance separating the target (10) from the same sensor (100), and determining (240) the morphology of the target (10) on the basis of the collection of weighted second values (SdixWi).

Abstract: A network system including: a first sensor device which includes a first sensor unit which detects an action of a detection object; and a first transmission unit which transmits first data regarding the action and first identification information to a server via a first base station: a second sensor device which includes; a second sensor unit which obtains sensing data; and a second transmission unit which transmits second data including the sensing data and second identification information to the server via a second base station; wherein the server is configured to: associate the first and second data based on the detection of the action; to access predetermined normal data correlating data; and, detect an abnormal condition if a combination of the action detected via the first sensor unit and the sensing data obtained by the second sensor unit conflict with the correlated normal data.

Abstract: An electrical connector assembly includes a first connector subassembly associated with a removable component, and a second connector subassembly associated with a host component to which the removable component is removably connectable. One and only one of the first and second connector subassemblies is floatable relative to its associated component.

Abstract: An apparatus is provided for detecting the presence of an obstruction with respect to a height-adjustable bed. The apparatus includes one or more sensors coupled to the bed. At least one of the sensors has an output signal which is variable in response to changes in a weight applied to the support surface. The apparatus also includes a controller having inputs configured to receive the output signals from the sensor or sensors. The controller is configured to monitor the output signals, and turn on a room light if a change in position of a body relative to a support surface of the bed is detected.

Abstract: Power is supplied to an ECU (20) from an on-vehicle battery (41). When an ignition switch (42) is switched from the OFF state to the ON state upon vehicle engine start, the ECU (20) is switched from the power saving mode to the normal mode and a CPU (31) executes initial processing. Moreover, when a user puts on a seat belt and a seat belt switch (44) is switched from the ON state to the OFF state, the ECU (20) is switched from the power saving mode to the normal mode and the CPU (31) executes the initial processing. Thus, the initial processing is executed at a comparatively short interval and it is possible to improve the reliability of the CPU (31).

Abstract: Devices, systems, and methods are disclosed for altering permitted settings of a vehicle according to a driver identified through short range wireless communication. The vehicle captures a unique identifier from a wireless communication device of the driver of the vehicle. This unique identifier is used to reference a database to determine the identity of the driver as well as settings for the driver created by a controlling authority. The controlling authority may be, for instance, a parent or employer of the driver. The settings may limit certain devices within the vehicle and/or the vehicle itself. Speed control settings, radio settings, wireless communication device settings, and various other settings are all possible to limit distractions to the driver. Further, the settings may be influenced by the number or identities of passengers within the vehicle.

Abstract: The present invention teaches and discloses method and apparatus for alerting a grocery store check out cashier of merchandise placed on the bottom tray of a typical grocery shopping cart. A passive RFID transponder is incorporated into the structure of the cart which when interrogated by an associated reader, located at the cashier's check out station, responds with a signal verifying the presence, or absence, of an unseen item upon the carts bottom tray.

Abstract: A patient position pad is provided that includes a timer. The patient position pad is configured to detect the position of a patient. The timer is configured to track the useful life of the patient position pad.

Abstract: The recognition of seat occupancy of a seat is achieved by recording at least one measured signal by way of a seat occupancy sensor. The measured signal is allocated a weight signal by way of an allocation rule, which is representative of a weight with which the seat is occupied. The allocation rule is altered when the weight signal over the course of time is first greater than a given upper threshold and when further, during a given first duration the weight signal lies in a first weight range at a weight zero value. The allocation rule is altered such that the then current measured signal is allocated the weight signal reduced by a given percentage from the weight signal. The allocation rule is further altered when the weight signal lies around the weight zero value in a given second weight range during a given second duration, which is much longer than the first duration.

Abstract: A vehicle seat pressure sensor includes a light source, a non-fiber optical polymer sheet, a boundary layer and a detection unit. The non-fiber optical polymer sheet is composed of non-woven flexible optical polymer material and has a first surface with a peripheral edge surrounding the first surface. The peripheral edge of the optical polymer sheet is aligned with the light source such that light emitted from the light source projects into the optical polymer sheet through the peripheral edge. The boundary layer is disposed along the first surface of the optical polymer sheet. The detection unit is disposed relative to the optical polymer sheet to detect changes in attenuation of light emitted from the peripheral edge of the optical polymer sheet in response to elastic deformation of the boundary layer and the optical polymer sheet.

Abstract: A method includes measuring a first frequency response of an electrode at a first frequency across a range of environmental conditions, measuring a second frequency response of the electrode at a second frequency across the range of environmental conditions, and comparing the first and second frequency responses measured to define a data set representing an effect of the environmental conditions. An occupant detection system includes an electrode and a detector circuit. The detector circuit is configured to measure an actual frequency response of the electrode and compare the actual frequency response to the data set to determine the effect of the current environmental condition.

Abstract: An occupancy detection system includes a signal generator coupled to an electrode, the signal generator configured to output a first signal at a first frequency and a second signal at a second frequency. The system further includes a voltage detection circuit connected to an output terminal of the signal generator and to an input terminal of the electrode, wherein the voltage detection circuit is configured to measure a first voltage responsive to the first signal at the first frequency and a second voltage responsive to the second signal at the second frequency. A control module in communication with the voltage detection circuit is configured to detect a state of occupancy based on the first voltage and the second voltage.