# Patent

## Title
Vehicle-based vehicle occupant reminder using capacitive field-based sensor

## Abstract

Methods and apparatus are provided for providing an indication to a person external to a vehicle, of an occupant inside the vehicle. The method comprises determining whether an occupant is in a vehicle, based on a capacitance measured within the vehicle; sensing whether an ignition of the vehicle is in an off position; detecting whether a first door coupled to the vehicle has been opened and closed, if the vehicle ignition is in an off position; if the first door has been opened and closed and an occupant is sensed in the vehicle, measuring a first time (T1) beginning from the instant the first door is closed; and activating the alert, if T1 is greater than a predetermined threshold time.

## Background
TECHNICAL FIELD
The present invention generally relates to alert systems, and more particularly a system for alerting a person outside of a vehicle of the presence of an occupant inside the vehicle.
BACKGROUND
Research has shown that an occupant who is left in a closed, parked vehicle for an extended amount of time on a hot or sunny day may face the possibility of suffering from a physical injury due to the heat and humidity that may be present in the automobile. Several types of products are available that provide various safety features intended to prevent injuries of these types. One common product used by drivers or adults responsible for transporting children is a child safety seat.
For the most part, child safety seats have been designed to accommodate and protect a child in the event of a vehicular collision. In recent years, child seat technology has become more sophisticated. Some child seats are now configured to detect the presence of a child in the child seat. Other child safety seats may operate in conjunction with some type of wireless transceiver, wherein the child seat sends signals to the transceiver relating to the presence of a child within the seat.
Although child seat assemblies of these types are useful, they may present certain drawbacks. For example, the wireless transceiver is typically capable of being carried from location to location. Thus, if a driver is in possession of the transceiver and fails to provide it to a subsequent driver, the subsequent driver may not receive the alert from the transceiver. Therefore, the subsequent driver will not be notified or reminded of the presence of the occupant in the vehicle. Moreover, because the wireless transceiver is transportable, it may become misplaced or may be lost.
Furthermore, child seat assemblies of this type are not useful in the protection of other occupants, such as older children or persons who do not fit into the child seat and who may be inadvertently left in an unattended, closed vehicle.
Accordingly, it is desirable to provide a system that is capable of alerting a person or driver who is outside of an automobile to an occupant inside of the automobile. In addition, it is desirable to provide an alert system that is useful for all drivers who operate the automobile. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.
BRIEF SUMMARY
A method is provided for alerting a person outside of a vehicle of an occupant in the vehicle. The method comprises the steps of determining whether an object in the vehicle is an occupant, based, in part, on a capacitance measurement of the object; sensing whether an ignition of the vehicle is in an off position; detecting whether a first door coupled to the vehicle has been opened and closed, if the vehicle ignition is in an off position; if the first door has been opened and closed, measuring a first time (T1) from an instant the first door is closed to an instant after the first door is closed; and activating the alert, if T1 is greater than a predetermined threshold time (Tthreshold).
Another method is provided for alerting a person outside of a vehicle of an occupant in the vehicle. The method comprises determining whether an object in the vehicle is an occupant, based, in part, on a capacitance measurement of the object; sensing whether an ignition of the vehicle is in an off position; detecting whether a first door coupled to the vehicle has been opened and closed, if the vehicle ignition is in an off position; sensing whether the first door and a second door have been locked; and if the first and second doors have been locked and an occupant is in the vehicle, activating the alert.
An apparatus is provided for indicating to a person external to a vehicle, of an occupant inside the vehicle, where the vehicle has a seat and at least a first and a second door. The alert system comprises a capacitor sensor, controller, door sensor, ignition indicator, and an alert. The capacitance sensor is operatively coupled to at least a portion of the vehicle to measure a capacitance of an object in the vehicle. The controller is electrically coupled to the capacitance sensor and configured to determine whether the object is an occupant, based in part, on the measured capacitance of the object in the vehicle. The door sensor is coupled to the controller and configured to sense the opening and closing of the first and second doors. The ignition indicator is coupled to the controller and configured to sense whether an ignition of the vehicle is in an off position. The alert is electrically coupled to the controller and configured to produce a signal external of the vehicle if the controller determines the object is an occupant and if after the first door was closed, the second door has not been opened within a predetermined threshold time.
Another apparatus is provided for indicating to a person external to a vehicle, of an occupant inside the vehicle, where the vehicle has a seat and at least a first and a second door. The alert system comprises an electric field sensor, controller, door sensor, ignition indicator, and an alert. The electric field sensor is operatively coupled to at least a portion of the vehicle to measure a capacitance of an object in the vehicle. The controller is electrically coupled to the electric field sensor and configured to determine whether the object is an occupant, based in part, on the measured capacitance of the object in the vehicle. The door sensor is coupled to the controller and configured to sense the opening, closing, and locking of the first and second doors. The ignition indicator is coupled to the controller and configured to sense whether an ignition of the vehicle is in an off position. The alert is electrically coupled to the controller and configured to produce a signal external of the vehicle if the controller determines the object is an occupant and if after the first door was closed, the first and second doors are locked.



BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and
FIG. 1 is a block diagram of an exemplary occupant alert system;
FIG. 2 is an illustration of an exemplary seat that may be employed in the exemplary occupant alert system depicted in FIG. 1; and
FIG. 3 is a flow diagram of an exemplary method for implementing an occupant alert system.



DETAILED DESCRIPTION
The following detailed description of the invention is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any theory presented in the preceding background of the invention or the following detailed description of the drawings.
An exemplary embodiment of an occupant alert system 100 for an automobile 102 is provided and shown in block diagram form in FIG. 1. The occupant alert system 100 is implemented into the automobile 102 to alert persons external to the automobile 102 of an occupant that may be inside the automobile 102. The occupant alert system 100 includes at least one electric field sensor 104 that communicates capacitance data to a sensor electronic control module (ECM) or controller 106. The sensor ECM 106 is also operatively coupled to a door sensor 108 and a portion of an ignition module 110. The sensor ECM 106 is configured to receive signals from the door sensor 108 indicating whether one or more of the doors 124, 126 coupled to the automobile 102 is opened or closed and from the ignition module 110 as to whether the ignition 114 has been turned off. An alert ECM 116 is also coupled to the sensor ECM 106 and is configured to cause an alert or alarm in the event an occupant is left in the vehicle for over a predetermined amount of time. Each of these components will now be discussed.
The electric field sensor 104 is at least partially located in a seat 118 that is disposed within the automobile 102, and is configured to sense a capacitance field of an object or occupant that may be present on the seat 118. In one embodiment, the electric field sensor 104 is configured to compare the sensed capacitance data with a predetermined capacitance to determine whether the object is an occupant. Any one of numerous types of electric field sensors that may be appropriate for use in an automotive vehicle may be employed, such as, for example, a capacitance sensor. Generally, the electric field sensor 104 includes a transmitter 130 and a receiver 132. The transmitter 130 is configured to transmit signals relating to the detected capacitance field. The transmitted signals are received by the receiver 132.
The transmitter 130 may be located in any one of the seats 118 that may be disposed within the automobile 102, including the rear row or rear seats. More preferably, the transmitter 130 is located in at least one of the seats or rows of seats where an occupant may sit or lay, a child seat may be located, or where a driver may not remember to look for an occupant. As illustrated in FIG. 2, the transmitter 130 may be positioned on any portion of the seat 118. For instance, the transmitter 130 may be positioned in the bottom seat cushion, or within the back cushion. Depending on the design of the seat 118 itself, the transmitter 130 may be placed under or in the upholstery of the seat 118 or embedded within the foam cushion of the seat. The receiver 132 can be placed in any other section of the automobile 102 that is in sufficient proximity to the transmitter 130 to thereby receive transmitted signals, including, but not limited to, anywhere in or on the seat 118. After the appropriate capacitance data of the object is collected it is then communicated to and received by the sensor ECM 106.
Although only one electric field sensor 104 is referred to herein, those skilled in the art will recognize that any number of electric field sensors may be used. Moreover, the electric field sensor 104 can alternatively be configured to produce an electric field and to provide a measurement that measures the change in the electric field when an object or occupant is in the sensing range of the electric field sensor 104, instead of measuring capacitance.
Returning to FIG. 1, the sensor ECM 106 includes at least a processor 120 that operates in conjunction with a memory 122. The processor 120 is configured to compare the capacitance sensed by the electric field sensor 104 to a predetermined capacitance (Cp), to determine whether or not an occupant is on the seat 118. The predetermined capacitance may be a number within a range that may identify whether an occupant is in the seat. The predetermined capacitance may be set and programmed to a preferred setting into the processor 120 and/or memory 122 at any time during manufacture of the automobile, or alternatively, the predetermined capacitance may be subsequently adjusted.
As previously mentioned, the sensor ECM 106 is also coupled to a door sensor 108. The door sensor 108 is coupled to a door 124 of the automobile 102 and configured to provide data to the sensor ECM 106 as to whether the door 124 has been opened and closed and/or locked and unlocked. Any one of numerous types of sensors suitable for detecting whether a door 124 is open, closed, locked, or unlocked may be employed. The door sensor 108 may also be coupled to a second door 126, or some or all of the remaining doors, so as to determine whether those doors have been opened or closed or locked or unlocked. Alternatively, separate door sensors 108 may be coupled to the other doors 126 to sense the opening or closing or locking or unlocking of the doors.
The sensor ECM 106 is also in communication with the ignition module 110. The sensor ECM 106 senses whether the ignition is off to determine whether to activate the system 100. The door sensor 108 and ignition module 110 each provide serial data to the sensor ECM 106 that aid the sensor ECM 106 in the determination of whether to send a signal to the alert ECM 116.
A timing mechanism 128 is coupled to the door sensors 108. The timing mechanism 128 is configured to activate and measure various time periods, such as from the moment that the door sensor 108 senses that the first door 124 has been open and subsequently shut, to the moment the second door 126 has been opened. The timing mechanism 128 may be configured to reset when the second door 126 has been shut and if the electric field sensor 104 senses an occupant is present in the automobile. The timing mechanism 128 may be integrated into a single component embedded in the system 100, or alternatively, incorporated into the sensor ECM 106, or can be a separate timer component. As appreciated by those with skill in the art, the timing mechanism 128 may also be set to measure any other time durations that may be useful in determining whether an occupant has remained in the automobile 102 for an unacceptable length of time.
The timing mechanism 128 sends the collected timing data to the sensor ECM 106, which compares the measured time with a predetermined threshold time (Tsafe) that may be stored in its memory 122. The predetermined threshold time is preferably an acceptable time period within which a driver or other person can reasonably attend to the occupant after the driver initially exits the vehicle from the first door 124. In one embodiment, the predetermined threshold time may be between about two and twelve (2–12) seconds, more preferably about ten (10) seconds.
If the sensor ECM 106 determines that an occupant is in the automobile 102 and, for instance, the occupant has remained in the automobile 102 for a time period that is greater than the predetermined threshold time or the doors 124, 126 have been locked with the occupant in the automobile, the sensor ECM 106 is configured to send a serial data message to the alert ECM 116 to activate an alert. The alert ECM 116 can be configured to produce any one of numerous types of alarm or alert mechanisms that can be used to notify the driver that an occupant may be in the automobile 102. In one embodiment, the alert ECM 116 is coupled to an automobile horn. As appreciated by those with skill, the horn can be a typical car horn sound, or a different sound that can be associated with an alert alerting others that an occupant may be in the automobile 102. In another embodiment, the alert ECM 116 can be coupled to a separate audible noise that is not associated with the car horn. In yet another embodiment, the alert ECM 116 may be coupled to a visual alert, such as flashing car headlights or some other type of visible indication. As those familiar with the art may appreciate, one or more of these alerts may be used in conjunction with one another. In yet another embodiment, the form of alert may be a few short horn sounds.
Turning to FIG. 3, an embodiment of one of the methods by which to operate the occupant alert system 100 will now be discussed. Although each step herein is discussed as if they are to be performed in a particular order, it will be appreciated that some of the steps need not be performed in the described order and that some steps may be performed simultaneously, or before or after another step that may be described in the method. In any event, each of the steps referred to in FIG. 3 are referenced herein by parentheticals.
While the automobile 102 is in operation or when the system 100 is not activated, the system 100 is in a sleep or standby mode (202). The system 100 is activated when the sensor ECM 110 senses that the ignition 114 has been shut off (204). Then, the sensor ECM 110 detects via the door sensor 108 whether a first door 124 is opened and subsequently shut (206). If the first door 124 is opened, but not shut, the sensor ECM 106 causes the system to return to standby mode (250). If the first door 124 is opened and subsequently shut, the sensor ECM 106 causes the electric field sensor 104 to measure the capacitance of the object or occupant that is present on the seat 118 (208). Specifically, the electric field sensor 104 senses the capacitance and sends the data to the sensor ECM 106 to compare the sensed capacitance (C1) with a predetermined capacitance (Cp) to identify whether an occupant is in the automobile. If C1 is not equal to Cp, or if Cp is a range, if C1 is not within the range of Cp, the ECM 106 assumes that no occupant is present on the seat 118 and the system 100 returns to standby mode (250). If the electric field sensor 104 senses a C1 that is equal to or within the range of Cp, the timing mechanism 128 is activated and begins to track time from the closing of the first door 124 (T1) so that a determination can be made as to whether the tracked time (T1) becomes greater than the predetermined threshold time (Tsafe) (210). Alternatively, if C1 is equal to or within the range of Cp, thus indicating the presence of an occupant, and the sensor ECM 106 detects that all of the doors 124, 126 are locked (209), time is not tracked; however, the sensor ECM 106 sends a serial data message to the alert ECM 116 to activate the alert (214).
If time tracking begins, the sensor ECM 106 then detects whether the second door 126 has been opened within Tsafe (212). If T1 is greater than Tsafe, then the sensor ECM 106 sends a serial data message to the alert ECM 116 to activate an alert (214). If T1 is less than Tsafe, then the timing mechanism 128 is reset (216) to track additional time (T2). The sensor ECM 106 then senses whether the second door 126 has been shut (218). If the second door 216 has been shut, then the sensor ECM 106 takes another capacitance measurement (C2) and identify whether C2 is equal to or within the range of Cp (220). If C2 is not equal to or not within the range of Cp, then the system 100 returns to standby mode (250). If C2 is identified as being equal to or within the range of Cp, then the sensor ECM 106 compares T2 to Tsafe (222). If T2 is less than Tsafe, then the system 100 continues to detect whether the second door 216 is shut. If T2 is greater than Tsafe, then the sensor ECM 106 sends a serial data message to the alert ECM 116 to activate the alert (214).
While an exemplary embodiment(s) has been presented in the foregoing detailed description of the invention, it should be appreciated that a vast number of variations exist. It should also be appreciated that these exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing a preferred embodiment of the invention. It being understood that various changes may be made in the function and arrangement of elements described in an exemplary preferred embodiment without departing from the spirit and scope of the invention as set forth in the appended claims.

## Claims

1. A method for providing an alert to a person outside of a vehicle of an occupant in the vehicle, comprising the steps of:
determining whether an object in the vehicle is an occupant, based, at least in part, on a capacitance measurement of the object;
sensing whether an ignition of the vehicle is in an off position;
detecting whether a first door coupled to the vehicle has been opened and closed, if the vehicle ignition is in an off position;
determining whether a second door coupled to the vehicle has been opened;
if the first door has been opened and closed, the second door has been opened, and an occupant is sensed in the vehicle, measuring a first time (T1) from an instant the first door is closed to an instant when the second door is open; and
activating the alert, if T1 is greater than a predetermined threshold time (Tthreshold).

2. The method of claim 1 wherein determining whetter the object in the vehicle is an occupant further comprise:
sensing the capacitance of the object it is positioned on a seat; disposed within the vehicle; and
determining that an object is an occupant if the sensed capacitance is equal to a predetermined capacitance.

3. The method of claim 1, wherein the predetermined threshold time is between about 2–12 seconds.

4. The method of claim 1, wherein the alarm system is an audible indicator.

5. The method of claim 4, wherein the audible indicator is a horn coupled to the vehicle.

6. The method of claim 1, wherein the alarm system is a visual indicator.

7. An alert system for providing an indication to a person external to a vehicle, of an occupant inside the vehicle, the vehicle having a seat and at least a first and a second door, the system comprising:
an electric field sensor operatively coupled to at least a portion of the vehicle to measure a capacitance of an object in the vehicle;
a controller electrically coupled to the electric field sensor and configured to determine whether the object is an occupant, based at least in part, on the measured capacitance of the object in the vehicle;
a door sensor coupled to the controller and configured to sense the opening and closing of the first and second doors;
an ignition indicator coupled to the controller and configured to sense whether an ignition of the vehicle is in an off position; and
an alert electrically coupled to the controller and configured to produce a signal external of the vehicle if the controller determines that the object is an occupant and if, after the first door was closed, the second door has not been opened within a predetermined threshold time.

8. The system of claim 7, further comprising:
a timer coupled to the door sensor and controller.

9. The system of claim 7, wherein the alert is an audible indicator.

10. The system of claim 9, wherein the alert is a vehicle horn.

11. The system of claim 7, wherein the alert is a visual indicator.

12. The system of claim 7, wherein the visual indicator is a flashing light.

13. The system of claim 7, wherein the electric field sensor further comprises a transmitter and a receiver.

14. The system of claim 13, wherein the transmitter is coupled to at least a portion of the seat.