Detecting life by means of co2 in an enclosed volume

[0001] Monitoring of CO2 and temperature levels detects human or animal life and life threatening conditions in vehicle cabins. The detection system uses CO2, temperature and vehicle ignition sensors to monitor the rate of change of these inputs. The sensing system includes identification of vehicle location and operates regardless of the presence or absence of vehicle power. The detection system can respond appropriately to detected events by communicating via cellular and/or satellite transceiver(s), and can respond to hazardous conditions within the vehicle by taking other actions. The detection system employs a graduated warning system of increasing severity.

[0002] The present disclosure may be better understood with reference to the following drawings. The elements in the drawings are not necessarily to scale, emphasis being placed on clearly illustrating the principles of the disclosure. Further, like reference numerals indicate corresponding parts throughout the following drawings.

<figref num="1">[0003] FIG. 1 illustrates a system for monitoring CO2 levels within an enclosed volume, according to an exemplary embodiment of the present disclosure.</figref><figref num="2">[0004] FIG. 2A is a flowchart illustrating a method of monitoring CO2 levels within an enclosed volume, according to an exemplary embodiment of the present disclosure. [0005] Figure 2B is a continuation of the flowchart of Figure 2A. [0006] Figure 2C is a continuation of the flowchart of Figure 2A. [0007] Figure 2D is a continuation of the flowchart of Figure 2A.</figref><figref num="3">[0008] FIG. 3 illustrates a CO2 sensor and sensor controller, according to an exemplary embodiment of the present disclosure;</figref><figref num="4">[0009] FIG. 4 shows exemplary nominal CO2 decay rates compared to test data.</figref>

[0010] FIG. 1 illustrates a CO2 detection system 100 according to an exemplary embodiment of the present disclosure. System 100 includes CO 2 sensor 101 , position sensor 102 , temperature sensor 108 , power supply 109 , sensor controller 107 , communication system 106 and (possibly) accelerometer 110 , all communicating via network 105 . System 100 provides an alert upon sensing the presence of unmanned object 103 within enclosed volume 104, as discussed further herein. The unmanned object 103 may be a child or infant in a child seat, an adult unable to exit the vehicle alone, an animal, or the like. Said enclosed volume 104 is an automobile or some other enclosure, such as a mobile enclosure for transporting humans or animals, or a stationary enclosure such as a refrigerator or freezer, or any reasonably airtight space in which a mammal may be enclosed.

[0011] In addition, the enclosed volume 104 exchanges low-level air with air having a known and relatively low concentration of CO2, such as atmospheric air, which has an average CO2 concentration of about 400 ppm. Low air exchange rate is roughly the (1) hourly air exchange (ACH) rate for a typical stationary vehicle. The system may allow a range of ACFI values. The system uses ACH values to predict future CO2 levels from current volumetric conditions. The tolerance around ACH and associated CO2 projections allow the system to accommodate different volumes.

[0012] In one embodiment, the CO2 sensor 101 comprises a low power, self-calibrating, humidity compensated sensor. The CO2 sensor 101 samples the air within the enclosed volume 104 and records the CO2 level multiple times per second to determine the first, second and higher order rate of change of the CO2 level, i.e. the CO2 level above the threshold corresponding to nominal air ~400ppm.

[0013] The sensor controller 107 controls the operation of the CO2 sensor 101 and other components of the system 100. As shown in FIG. Although the sensor controller 107 is shown in FIG. 1 as a separate component from the CO2 sensor 101, the temperature sensor 108, and other components, in some embodiments multiple components are packaged together in one device. The sensor controller 107 is further discussed herein with respect to FIG.

[0014] The temperature sensor 108 provides temperature data to the temperature sensor controller 107 . In one embodiment, the temperature sensor 108 is a low power consumption device. In one embodiment, the sensor controller 107 samples the temperature level via the temperature sensor 108 multiple times per second to determine the temperature within the enclosed volume. The temperature sensor 108 also provides the humidity level in one embodiment.

[0015] The power supply 108 provides power to the system 100. FIG. The power supply 108 may be a cigarette lighter (not shown) or an interface to the vehicle power supply via an ODB-III port. Alternatively, the power supply 108 may be the power supply that supplies the car's radio. In other embodiments, other power sources such as solar power or other energy harvesting mechanisms are used.

[0016] The power source 108 further comprises an internal rechargeable battery (not shown). This battery allows the system to operate for at least a week without recharging and allows the system to operate outside the vehicle without vehicle power. The battery is automatically charged when the vehicle is running or powered.

[0017] The sensor controller 107 determines whether the vehicle is active using readily available vehicle active signals (available with ODBIII and car radio connections) or using voltage thresholds to the vehicle power supply. When the vehicle is active, it actively charges the vehicle's battery, increasing the system voltage above ~13VDC. Furthermore, modern vehicles generally only power the cigarette lighter when the vehicle is active.

[0018] The position sensor 102 determines the position of the enclosed volume 104 to transmit position information when the system 100 issues an alarm, as discussed further herein. The position sensor 102 may be a GPS transmitter. The position sensor 102 may include a clock that is used to update the system time and provide the sensor controller 107 with the current time.

[0019] In one embodiment, the communication system 106 comprises a satellite or cellular transceiver or Global System for Modem (GSM) modem for communicating vehicle and occupancy status. The communication system 106 also receives and transmits both voice and data communications.

[0020] In one embodiment, the accelerometer 110 comprises a standard accelerometer that operates when a vehicle door is opened and closed. Accelerometers may also be activated in other situations such as a vehicle crash or when a person moves around the vehicle. Activation of the accelerometer activates (awakens) the system 100, as discussed further herein.

[0021] The network 105 may be any type of network known in the art or developed in the future, such as Internet backbone, Ethernet, Wifi, WiMax, broadband over powerline, coaxial cable, and the like. The network 105 may be hardware, software, or any combination of both.

[0022] As discussed further herein, in the exemplary embodiment, when the system 100 detects an unsafe CO2 level, first a first user (first user 120), then a second user (second user 121), and then emergency management (EMS 122) are alerted.

[0023] Figures 2A, 2B, 2C, and 2D illustrate a method 200 for detecting CO2 within an enclosed volume, in an exemplary embodiment of the present disclosure. Referring to FIG. 2A, at step 201 of method 200, the system 100 (FIG. 1) is operated to wake from "sleep" mode. The system polls the sensor at regular time intervals and sleeps during the interval to save power. Based on these sensor inputs and associated calculations, the system can be in "deep sleep" or "active mode." In one scenario, the accelerometer 110 (FIG. 1) detects an event, such as opening or closing a car door, to activate the system 100 . In another scenario, the CO2 sensor 101 (FIG. 1) detects a CO2 level equal to or above the threshold, and activates the system 100 in an "active mode." In other scenarios, the system may enter active mode when external power becomes available. When the system is in "deep sleep" mode, the communication system 106 and position sensor 102 are powered down to conserve system power. When the system is activated to wake up, power is supplied to the communication system 106 and the position sensor 102 .

[0024] In step 202 of method 200, the sensor controller 107 queries the sensors to determine system parameters. In this regard, the sensor controller obtains the current CO2 level from the CO2 sensor 101, the current temperature and humidity from the temperature sensor 108, the position data from the position sensor 102 (if powered), and so on.

[0025] At step 206, the system 100 calculates the required running average. In this regard, the sensor controller 107 calculates all necessary running averages to eliminate noise in the sensor data. Specifically, it calculates a running average of current temperature, current CO2 level, current CO2 index decay rate, and empirically determined hourly air exchange (ACH). The system 100 analyzes the operating average decay rate of CO 2 in the enclosed volume 104 . At some point (FIG. 4), the enclosed volume 104 changes from the activated state to the deactivated state. The operating average decay rate CO2 will then follow one of four possibilities as long as the CO2 level is above the nominal atmospheric CO2 threshold at time To: 1. The operating average CO2 will increase.

2. The operating average CO2 decreases, but not as fast as would be expected given the estimated ACH value of the enclosed volume.

3. The operating average CO2 decays exponentially within the tolerance for a given ACH.

Four. The operating average CO2 decreases more rapidly than expected given the estimated ACH value of the enclosed volume.

[0026] In Scenarios 1 and 2 above, there are other sources of CO2 in the system, likely produced by aerobic respiration from mammals. Scenario 3 is the expected scenario. The CO2 level in the atmosphere slowly exchanges with the concentration value in the enclosed space until it decays exponentially to equality. The final scenario would be that either a door, window or other opening would change the ACH value of the enclosure.

[0027] At step 207, the system determines whether the current CO2 level is greater than an ambient threshold of 450 ppm. If the CO2 level does not exceed 450 PPM, the system enters sleep mode at step 205 .

[0028] At step 211, the system determines whether the CO2 level decays fast enough. In this regard, the system queries whether the CO2 level is greater than the nominal high threshold CO2 decay rate, which in one embodiment is based on a threshold of 10% which would be acceptable close to the expected exponential decay. Nominal CO2 decay rate is determined from a combination of experimentally determined and test values. Additionally, the nominal CO2 decay rate may be adjusted over time for a particular enclosed volume based on CO2 decay measurements for that particular enclosed volume during system run.

[0029] FIG. 4 shows exemplary nominal CO2 decay rates compared to test data obtained from testing a full-size sedan with a threshold of 450 ppm. To on the chart of FIG. 4 indicates the point in time when the closed volume is deactivated. The operating average CO2 line 414 plots the CO2 average during operation as described herein. Running averages typically change only a few ppm over a 15 second interval. Planned CO2 line 411 plots the planned CO2 decay rate. (Planned CO2 line 411 tracks operating average CO2 line 414 in the example of FIG. 4).

[0030] The operating average decay rate must consistently exceed the projected rate prediction for each iteration over several minutes or the timer is reset. Nominal CO2 decay y-line 410 plots nominal CO2 decay against volume and temperature. A fast CO2 decay threshold line 412 indicates a threshold below which CO2 levels decay faster than expected. The slow CO2 decay threshold line 413 indicates a threshold above which the CO2 velocity decays too slowly, indicating a potentially dangerous situation in an enclosed vehicle.

[0031] Figure 4 graphically illustrates that CO2 levels increase when the actual decay rate is in region 401, indicating that a mammal may be left in the enclosed volume. If the actual decay rate is within region 402, the CO2 rate will decay slowly, indicating that mammals may be left in the enclosed volume. (Region 401 is substantially a subset of region 402). If the actual decay rate falls within region 403, the CO2 rate will decay correctly. If the actual decay rate falls within region 404, it indicates that the CO2 rate may be decaying too quickly, eg with an open window or door.

[0032] Returning to step 211, if the CO2 rate does not decay quickly enough, in step 211a the system switches from "deep sleep" to sleep mode to "active" mode with GSM/GPS enabled.

[0033] At step 211b, a first timer (Timer1) is incremented to begin timing a potentially dangerous situation in the enclosed volume 104 because the CO2 level is rising or not falling (decaying) quickly enough. The second timer (Timer2) and the third timer (Timer3) are canceled.

[0034] At step 211c, the system queries whether said first timer (Timer1) exceeds a predetermined value, in one embodiment a stable value of 5 minutes. The stabilization value is a well tested and determined duration to allow time for the CO2 level to stabilize to a uniform decay curve.

[0035] After the first timer exceeds a stable value, at step 211d, the system determines whether the enclosed volume 104 is activated or is being activated. If the enclosed volume 104 (eg, an automobile) is running or operating, the method continues at step 231 (FIG. 2C), as described below with respect to FIG. 2C.

[0036] If the enclosed volume is activated or not activated, the method proceeds at step 213 (Fig. 2B).

[0037] Returning to step 211, if it is false that the CO2 is not decaying fast enough (i.e., the CO2 level is decaying quickly), then at step 212, the system determines whether the CO2 level is less than 90% of the nominal value. 90% of the nominal value is an adjustable boundary in other embodiments). If the CO2 level is less than 90% of the nominal value, then at step 212a a third timer (Timer3) is incremented and Timer1 and Timer2 are cleared.

[0038] At step 212b, the system queries whether the third timer exceeds a predetermined value, a stable value, which in one embodiment is five minutes. The stabilization value is a well tested and determined duration to allow time for the CO2 level to stabilize to a uniform decay curve. If the third timer does not exceed the stable value, the system enters sleep mode at step 205 . If the third timer exceeds the stable value, then at step 212c the system queries whether window/door alarms are enabled. This step essentially asks that the user has set the system to request that alert. If so, the method continues at step 250 in FIG. 2D. If window/door alarms are not enabled, the method continues at step 212e (FIG. 2A), as discussed further herein.

[0039] Returning to step 212, in one embodiment, if the CO2 level is not less than 90% of the nominal value, in step 212d timer 2 is incremented and timers 1 and 3 are cleared. At step 212e, if timer 2 or timer 3 is greater than a predetermined period (15 minutes in the illustrated embodiment) and there are no alarms in the system, at step 212f GSM and GPS are disabled and the system enters deep sleep mode.

[0040] At step 2l2g, if this is the first state in which the system enters deep sleep mode, at step 2l2h, the CO2 decay rate is recorded and the method continues at step 205. If not, the method continues at step 205 .

[0041] Referring to Figure 2B, at step 213, the system queries to determine if the temperature is out of tolerance. If the temperature is not out of the acceptable range (below 60 degrees Fahrenheit or, in one embodiment, above 90 degrees Fahrenheit), the method restarts at step 205 in FIG. 2A.

[0042] If the temperature is out of the acceptable range, at step 214 the system queries to determine if this is the first state condition. If so, at step 219 the CO2 decay rate is logged for future use. In this regard, aggregated log values may be used to characterize the enclosed volume (eg vehicle) in order to increase the sensitivity of the algorithm in the future. At step 220, a first alert is sent indicating a life-threatening condition.

[0043] In one embodiment, the first alert is in text form to a first contact (eg, the prospective driver of the vehicle).

[0044] Returning to step 214, if not in the first state, then at step 215, the system queries whether the first timer has exceeded 7.5 minutes. This time period is exemplary and other time periods may be used in other embodiments. This 7.5 minute time difference gives the recipient of the first alert an opportunity to address the situation before another alert is sent.

[0045] If the period of time does not exceed 7.5 minutes, the system returns to sleep mode in step 205 (FIG. 2A). If the period exceeds 7.5 minutes, at step 216 the system queries to determine if it is the first state of the state. If so, in step 221 a second life-threatening alert is sent to the second contact.

[0046] In one embodiment, the second alert is in text form to the second contact.

[0047] Returning to step 216, if not the first embodiment, the system queries whether the first timer has exceeded 10 minutes. This time period is exemplary and other time periods may be used in other embodiments.

[0048] If the time does not exceed 10 minutes, the system returns to sleep mode in step 205 (Fig. 2A). If the period exceeds 10 minutes, then at step 218 the system queries to determine if it is the first state of the state. If so, in step 222 a third alert is sent.

[0049] In one embodiment, the third alert is in the form of a text or contact (call) to an emergency management system (eg, 911).

[0050] Return to step 218, if not in the first embodiment, return to sleep mode in step 205 (Fig. 2A). [0051] Return to step 211d (Fig. 2A), if the CO2 level does not decay fast enough, but the car starts/drives, in step 231 (Fig. 2C), the system queries whether the temperature is outside the nominal range. In one embodiment, the nominal range is above 60 degrees Fahrenheit and below 90 degrees Fahrenheit. If the temperature is within the nominal range, the system returns to sleep mode per step 205 (FIG. 2A). If the temperature is outside the nominal range, at step 232 the system queries whether the first timer has exceeded a predetermined value, which in this embodiment is 5 minutes. If the first timer does not exceed a predetermined value, the system returns to sleep mode for a short period of time, such as 15 seconds, in one embodiment at step 205 (FIG. 2A).

[0052] If the first timer exceeds a predetermined value, then at step 233 the system queries to determine if it is the first state of the state. If the first condition, then at step 236a the CO2 rate is logged and at step 236b the user is alerted to the condition via a first alert. In one embodiment, said first alert is a text sent to the first contact.

[0053] If step 233 determines that it is not in the first state, then in step 234 the system queries to determine if the first timer has exceeded another predetermined value, in this embodiment ten minutes. If the first timer does not exceed a predetermined value, the system returns to sleep mode for a short period of time, such as 15 seconds, in one embodiment at step 205 (FIG. 2A).

[0054] If the first timer exceeds a predetermined value, at step 235 the system queries to determine if it is the first state of the state. If so, in step 237 the user is alerted to the situation via a second alert. In one embodiment, the second alert is another text sent to said first contact.

[0055] At step 250 of FIG. 2D, if window/door alarms are enabled (per step 226 of FIG. 2A), the system queries to determine if the third timer has exceeded another predetermined value, in this embodiment five minutes. If the third timer does not exceed the predetermined value, the system returns to sleep mode for a short period of time, such as 15 seconds, in one embodiment at step 205 (FIG. 2A).

[0056] If the third timer exceeds a predetermined value, then at step 251 the system queries to determine if it is the first state of the state. If the first condition, then at step 252 the CO2 rate is logged and at step 253 the user is alerted to the condition via a first alert. In one embodiment, said first alert is a text sent to the first contact.

[0057] In addition to the alerts described herein, in some embodiments, the system can also be used as a panic button/SOS call, allowing a person within the enclosed volume to send a distress alert.

[0058] Figure 3 illustrates CO2 sensor 101, temperature sensor 108, accelerometer 110, and sensor controller 107 according to one embodiment of the present disclosure. The sensor controller 107 comprises system logic 320 and system data 321 , and in the exemplary sensor controller 107 system logic 320 and system data 321 are shown stored in memory 327 . System logic 320 and system data 321 may be implemented in hardware, software, or a combination of hardware and software.

[0059] The sensor controller 107 also includes a processor 330, which comprises a digital processor or other type of circuitry, to process and execute the system logic 320, if applicable. Processor 330 communicates with and drives other elements within the sensor controller 107 via local interface 324, which may include one or more buses. When stored in memory 327, system logic 320 and system data 321 can be stored and carried on any computer-readable medium for use by or in connection with a computer-based system, a system containing a processor, or other system capable of receiving and executing instructions from a logic circuit, processor, instruction execution system, apparatus, or device, such as an instruction execution system, apparatus, or device. In the context of this specification, a "computer-readable medium" may be any means capable of storing, storing, communicating, propagating, or transporting a program for use by or in connection with an instruction execution system, apparatus, or device. A computer readable medium can be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, device, or propagation medium.

[0060] System logic 320 performs the processes described herein with respect to Figures 2A, 2B, 2C, and 2D. System data 321 includes data collected by the CO 2 sensor 10101 , temperature sensor 108 , power supply 1088 , sensor controller 107 , communication system 106 , position sensor 102 and accelerometer 110 .

[0061] Referring to Figure 3, the communication system 106 may communicate with input devices (not shown), such as keyboards, switches, mice, and/or other types of interfaces. The communication system 106 may also communicate with or include a display device (not shown) that may be used to display data to a user. The communication system 106 may also communicate with, or alternatively comprise, a personal digital assistant (PDA), computer tablet device, laptop, portable or non-portable computer, cellular or mobile phone, or the like. The communication system 106 may also communicate with, or alternatively comprise, non-personal computers such as servers, embedded computers, microprocessors, or the like. The communication system 106 may also or alternatively include a local interface (not shown) for communication with a key fob or button or similar device that a user may use to disable an alarm, such as when the user receives an alarm and knows that no one is within the enclosed volume.

[0062] The communication system 106 may also interface with or include a GPS receiver or a cellular network.

[0063] The communication system 106, the position sensor 102, and the clock 323 are shown as part of the sensor controller 107 in the exemplary embodiment of FIG. In other embodiments, the communication system 106, position sensor 102, and/or clock 323 may be external to the sensor controller and/or part of the CO2 sensor or other sensor.