Abstract:
A chemical alert system for generating an alarm is described including a portable electronic device, preferably with telecommunication capabilities to allow for data and/or voice communication via private or public networks, and at least one chemical sensor integrated with the housing of the portable device and controlled by a chemical sensor processing unit, further comprising an alert discriminator receiving input based on measurements of the chemical sensor, performing a test on the input and based on an outcome of the test initiating the transfer of measurements of the chemical sensor to a remote processing facility.

Description:
FIELD OF THE INVENTION 
     The present invention relates to system for generating an alert or action in response to a change in the chemical composition of the surroundings of a portable electronic device such as a mobile phone, tablet and the like using a chemical sensor integrated within the housing of the device. 
     BACKGROUND OF THE INVENTION 
     Portable or mobile devices originally introduced as mobile phones or electronic agendas become more and more ubiquitous. As the processing power of their internal processors grows and equally the bandwidth for communication with stationary processors, such portable devices take on more and more the role of multi-purpose tools available to consumers and specialist users alike. 
     It has been recognized that portable devices can benefit from the presence of sensors capable of providing chemical analysis of materials brought into contact or the vicinity of the device. Whilst there are many possible applications for such sensors, it suffices to consider for example the analysis of air surrounding the portable device. Such an analysis can be useful for multiple purposes such as testing for hazardous gases, breath analysis for general medical purposes or driving fitness, and the like. 
     It has been known to incorporate gas sensors into portable sensor devices, such as mobile phones or tablet computers. For example, humidity sensors have been incorporated into some smartphone devices. However, humidity (i.e. gaseous water in air) is only one gas that might be of interest to a user of this type of device. Therefore, there is a need to provide devices that allow for measuring of a larger selection of gases, such as alcohol, CO, benzene, or groups of gases, which can e.g. be classified as certain smells or odors. 
     In case such gases can cause a hazard or pose an otherwise relevant condition for the user, it is desirable to use portable devices with integrated chemical sensors to issue an alarm or a notification to its user, to the surrounding of the user or to a remote location or to trigger an automated response. 
     As the issuing of a false hazard alarm or the triggering of an automated response can be disruptive and costly, it is seen as an object of the invention to improve the reliability of an alert system based on the use of portable devices with an integrated chemical sensor. 
     SUMMARY OF THE INVENTION 
     Hence, according to a first aspect of the invention, there is provided a chemical alert system for generating an alarm, the system including a portable electronic device, preferably with telecommunication capabilities to allow for data and/or voice communication via private or public networks, enclosed in a housing having preferably an air duct with an opening to the exterior of the housing and at least one chemical sensor controlled by a chemical sensor processing unit, further comprising an alert discriminator receiving input based on the measurements of the chemical sensor, performing a first test on the input and based on an outcome of the test initiating the transfer of measurements of the chemical sensor to a remote processing facility in case that, for example, the input from the chemical sensor unit indicates the presence of a chemical component in the sampled air beyond a test limit. 
     The test limit or threshold can be for example a concentration value or a condition or test procedure for the measurement results or any results derived from the measurements. 
     In a preferred embodiment the alert discriminator includes a two-stage test with a first threshold activating an alert mode in the portable device and a second threshold initiating either the transfer of measurements or the activation of an alarm mode of the portable device. In a variant of this embodiment, the passing of second threshold causes the activation of the alarm state, whereas the passing of the first threshold without passing of the second threshold initiates the transfer of measurements. 
     In a preferred embodiment of the invention the transfer of measurements includes measurements as used as input to the alert discriminator and additional measurements as gained from any prior stage in the processing of the measurements including raw data representing the direct sensor measurements. 
     An alarm of the portable device can include the generation of an acoustic alarm using internal resources such as a loudspeaker as integrated, or of an optical alarm using display or any in-built flash. Another possible alarm can be the initiation of a communication to a remote location, such as police or fire departments. An alarm can include a control event, in which the portable device controls one or more devices in its vicinity. It is further possible that the remote facility triggers the alarm by either assuming control of the portable device, other devices in its vicinity or by initiating communications to the remote locations. 
     Another aspect of the invention relates to a chemical alert system including a portable device as described above and a remote processing facility to receive the measurements of the chemical sensor as transferred by the portable device, whereby the remote facility is adapted to augment processing steps for the measurement of the chemical sensor as performed by the portable device. 
     The augmentation of the processing steps can include the re-processing of the measurements using more complex and powerful routines or models beyond the capacity of the portable device. The augmented processing can include the addition of further measurements or information from sources other than the portable device itself. Such sources can include other portable device in the vicinity of the portable device or the output of external sensors such as smoke or gas detectors. The further information may include publicly available information such as weather or other environmental conditions as may be useable for the interpretation of the measurement as performed by the portable device. 
     A preferred chemical sensor includes a sensor material, preferably in form of a layer, also denoted as receptor layer, to which an analyte may bond to and as such modify an electrical property of the sensor material such as its electrical conductance, e.g. metal oxide chemical sensors. It can also include a plurality of different sensors or an array of similar sensors. In such a sensor array, each sensor cell may provide a layer of a material exhibiting different absorption characteristics such that each cell of the sensor array may specifically be sensitive to a different analyte and as such may enable the portable electronic device to detect the presence or absence or concentration of such analyte. 
     A preferred sensor is combined with a least part of its control and read-out circuit onto a single semiconductor substrate. In a preferred variant this circuit is a CMOS circuit. 
     The portable device can be a smart phone, a handheld computer, a laptop, an electronic reader, a tablet computer, a game controller, a pointing device, a photo or a video camera, a digital music player, an electronic wrist watch, a personal health tracking device, a headset or a computer peripheral. Its housing is typically a shell of metal, glass, or plastic material and can be assembled as a unibody or from several parts. Enclosed in the housing are typically processors, drivers for parts such as screens, antennae, cameras, microphones and speakers as well as batteries to provide power to the device and its parts. A screen is typically arranged as a part of the housing or mounted behind a transparent window of the housing. 
     The duct acts as confinement for the air inside the housing and can take the shape of a tube or channel formed as part of the housing or as a separate part connected to an opening in the housing. It can be a single straight or curved duct. 
     The opening itself can be a dedicated opening thus exclusively connecting the chemical sensor to the outside. However, given that the manufacturers of portable electronic devices strive to maintain the housing as a good protection against humidity and water, it is seen as advantageous that the opening is shared with at least one further component of the portable device requiring a similar connection to the exterior, such as other sensors, for example humidity sensors, a loudspeaker, or a microphone. The opening can further be protected by a grill or a membrane to prevent bigger particles or unwanted components of the air from entering or blocking the duct. 
     The above and other aspects of the present invention together with further advantageous embodiments and applications of the invention are described in further details in the following description and figures. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1A  is a perspective view of a portable electronic device; 
         FIG. 1B  is a schematic view into part of the housing of the device of  FIG. 1A ; 
         FIG. 2  is a block diagram with components of a portable device in accordance with an example of the invention; 
         FIG. 3A  illustrates processing steps in accordance with an example of the invention; and 
         FIG. 3B  illustrates the effects of a recalculated chemical measurement in an example of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     The device of  FIG. 1A  is a portable electronic device such as a mobile phone. The housing  10  of the mobile phone includes a front side with a screen  101  and elements like buttons  102  to let a user interact with the phone. Also shown on the front side is an opening  103  for a loudspeaker. Further openings  104 ,  105  are located at a lower side wall of the housing  10 . It is well known to mount components like microphones and loudspeakers behind such openings. The phone includes one or two cameras  106 , and internally additional sensors (not shown) such as location sensors or GPS, and acceleration and orientation sensors in a manner well known. 
     Another opening  107  is located at the lower side wall. As shown in  FIG. 1B  the opening  107  is linked to a tubular duct  11  passing through the interior of the housing. A chemical sensor  12  and a humidity sensor  13  are both mounted along the duct  11  such that the sensitive areas of both sensors are essentially exposed air of the same composition entering the duct through the opening  107 . The actual size and shape of the duct  11  depends on the volume available and the nature of the chemical gas sensor  12  and the humidity sensor  13  can vary, but given the physical constraints of portable mobile devices the area of the opening is typically in the range of less than 10 square millimeters and in the present example actually about less than 3.1 square millimeters. 
       FIG. 2  shows a block diagram with the most important components of the portable device. In particular, the device includes a chemical gas sensor  21  integrated as part of a CMOS substrate  211  which has CMOS circuitry to control the basic functions and the basic readout of the sensor. The CMOS circuit can include for example the driver to switch the sensor and his heater on or off as well as A/D converters and amplifiers and an I2C bus controller to exchange data on an I2C bus  22 . The I2C bus connects the sensors with a sensor hub  23 . A further humidity and temperature sensor  24  is also linked to the I2C bus  22 . The chemical sensor  21  can be for example a single sensor, such as a metal oxide type sensor, or an array or assembly of several sensors. The chemical sensors can be either of the same type of metal oxide sensors but with a different sensing material or, either alternatively or in addition, sensors based on a different sensing principle. For metal oxide sensors, SnO2 (tin dioxide) is known to be sensitive to carbon monoxide, and WO3 (tungsten trioxide) is known to be sensitive to O3 (Ozone). 
     The sensor hub  23  provides a control and processing unit for more complex control and read-out functions of the chemical sensor  21  based on signals sent to or extracted from, respectively, the on-chip CMOS circuitry. The sensor hub  23  also controls other auxiliary sensors such as GPS, magnetometers, accelerometers and the like. 
     Further control and read-out function can also be performed by the central processing unit (CPU)  25  of the portable device, which in turn has read/write access to a memory  26 , which can include static or volatile memory or both as known in the art. The memory  26  typically stores the operating system of the device and can also be used to store application programs specific to the operation of the sensors of the portable device. The functions performed by the sensor hub and the sensor specific programs and program libraries as stored and executed by the CPU  25  form a chemical processing unit capable of transforming the measurements of the sensor into a result which can be displayed or otherwise communicated to the user of the portable device. 
     The CPU  25  and the memory  26  include and execute an alert discriminator in form of executable code. Functions of the alert discriminator are described in more detail below while making reference to  FIG. 3 . 
     In addition to the specific sensors as described above, the CPU is also connected to one or more sensors, for example the camera  271  or the microphone  272  also shown as the camera  106  and the microphone  104  of  FIG. 1 . Other sensors  273  such as location, acceleration and orientation sensors can be controlled by the sensor hub  23  as shown in the example. The sensors  271 ,  272  communicate with the CPU using their own interface units  274 ,  275 , respectively, which operate typically in complete independence of the chemical sensor  21 . 
     The device includes further well known input/output units  281  such as a touch sensitive display, virtual or physical keyboards and gesture tracking devices etc. The portable device as shown has a telecommunication circuit  282  comprising an antenna, driver circuits and encoding and decoding units as are well known in the art. Using such a telecommunication circuit, the device can connect to remote data processing and storage facilities  29  as shown. 
     The  FIG. 3  illustrate the operation of the above described elements in form of the schematic flow diagram of  FIG. 3A  and the basic diagram of  FIG. 3B , which illustrates the effect of the recalculation of a measurement or input as described below. 
     A first part  31  of the processes described are performed within and by the portable device. These local processes  31  performed by the portable device include the processes  32  performed by the alert discriminator. Other remote processes  33  involve and are performed within the remote facility. 
     The processes can be started for example by a user selecting an alert function or program on the portable device. Once started, the program keeps the portable device in a measurement loop. In the measurement loop measurements  311  are taken. The raw data from the measurement are then processed in a local processing step  312  performed by the chemical processing unit of the portable device. 
     The processing step  312  can include the application of standard routines and basic functions such as baseline corrections, polynomial fits, max-min determination, derivative or integral calculations, spectral analysis such as FFT or DFT, filtering, matrix calculations etc. The routines can further include more complex variants of statistical analysis tools such as Principal Component Analysis, Linear Discriminant Analysis and the like or neural network based tools such as Self-organizing Maps, Back Propagation, pattern recognition routines etc. 
     As the exact nature of the routines is not seen as a specific aspect of the present example, it suffices to refer to known libraries of such routines as available for example in MATLAB®. 
     The processed data are used as an input  313  to the alert discriminator  32 . Within the alert discriminator the input is used in a first test  321 . The first test compares the input  313  or values derived from the input  313  against a first condition or threshold. The threshold can be for example a concentration value for a specific gas or component or a plurality of concentrations for a spectrum of gases. 
     The portable device remains in its measurement loop, in case the first test  321  is negative, and after a delay  315  the sensor is automatically activated to perform another measurement  311 . The delay is chosen to repeat measurements as often as possible without however draining the battery of the portable device. Hence the delay  315  is automatically switchable depending on whether the portable device is charging and thus connected to an external power supply or not. 
     If the outcome of the first test  321  is however positive, the input  313  or values derived from the input  313  are subject to a second test  322 . Typically the second test  322  would set stricter conditions or thresholds. If the outcome of the second test  322  is positive, a local alarm  323  is raised instantly by either activating suitable resources within the portable device itself or by sending out communications using the communication facilities build into the portable device. The local resources can include the loudspeaker for generating an acoustic alarm, or the display or flash for generating an optical alarm or both. Depending on the type of portable device, the communication can be transmitted over a local or wide area network, or over the public telecommunication network. The communication can be an alert message to emergency services, to carers and/or to other authorities or people concerned with the well-being of the user. 
     The local alarm  323  can also be integrated into a home automation system and thus initiate an automated response to the alarm such as starting fire sprinklers, shutting down appliances, triggering a house alarm and the like. 
     If however the second test  322  is negative, a communication  324  to a remote processing center  33  is automatically sent out. The remote processing center  33  is adapted to process the chemical measurements  311  in processing steps  331  independently of the local processing  313  using either more powerful processing routines of the type described above when referring to the local processing  313  or additional inputs to the processing compared to the input used during the local processing  313 . The communication  324  therefore includes the raw data  312  or suitable data generated in processing steps which precede the calculation of the input  314 . 
     The additional input can be drawn from sources  332  external to the portable device. These external sources can include other portable devices with the same or a similar type of integrated chemical sensor. The sources can include information collected from stationary sensors such as stations gathering pollution data or permanently installed chemical sensors. The sources  332  can include publically available data such as weather data, or information about chemical or other environmental accidents affecting the location of the portable device. When collecting the external information, the remote processing can include a system to activate an external sensor, for example by initiating a chemical measurement using a portable device in proximity to the portable device and comparing the results as gained from the two portable devices. 
     As output of the remote processing  331  at the remote facility  33 , a new and likely improved result  333  is available. This re-calculated result can be applied in various ways. It can for example be re-tested for the first and second tests  321 , 322  as described above or any equivalent tests. The re-testing can determine whether or not the input should have resulted in a negative outcome of the first test  321 , in which case the portable device resumes its monitoring or measuring loop. Alternatively, the re-testing can determine whether or not the input gives a positive result at the second test  322 , in which case the portable device raises a local alarm  323 . As a matter of course, the remote facility is best enabled to raise alarms  334  in parallel to a transmission  335  of the re-calculated input  333  back to the portable device. 
     The diagram of  FIG. 3B  illustrates the effect of the re-calculations regarding the steps described above. It shows an initial locally calculated input  314  having passed the first test  321  but not the second test  322 . As a result of the remote re-calculation the recalculated input  333  can be found either below the threshold set by the first test  321  or above the threshold set by the second test  322  as is indicated by the dashed arrows in  FIG. 3B . In the case of such outcomes of the re-calculation the increased accuracy of the remote calculation increases the certainty of the alarm raising process by effectively narrowing the zone of uncertainty between the two tests  321 ,  322 . It should be noted, however, an input  333  after re-calculation can remain within the zone of uncertainty between the two levels set by the respective tests  321 ,  322 . Such an outcome would require another handling beyond the scope of this description. 
     While there are shown and described presently preferred embodiments of the invention, it is to be understood that the invention is not limited thereto but may be otherwise variously embodied and practised within the scope of the following claims. For example, it should be noted that the first and second test as described above can be replaced by a single test, a negative outcome of which sends the portable device into its measuring loop as described above, whereas a positive outcome initiates the transmission of the measurements to the remote processing facility for re-calculation. In such an example, an alarm would be raised only after a recalculation of the measurement.