Abstract:
An apparatus ( 10 ) is provided for detecting an atmospheric component. The apparatus, capable of being inserted into an electronic device ( 30 ) having an imager ( 36 ) and a processor, comprises a substrate; one or more calorimetric reagents ( 14 ) positioned on the substrate; one or more reference colors ( 16 ), each associated with one of the one or more colorimetric reagents; and data bars ( 18 ) positioned on the substrate depicting information about the one or more colorimetric reagents; wherein, when the apparatus is inserted in the electronic device, the imager is capable of detecting colors of the colorimetric reagents based upon the one or more reference colors and information from the data bars, the processor determining whether an atmospheric component is present based upon whether any colors of the colorimetric reagents have changed.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention generally relates to a device for determining the presence of an unwanted environmental agent and more particularly to a universal device for alerting the device user and others of the presence of an unwanted environmental agent.  
       BACKGROUND OF THE INVENTION  
       [0002]     First responders, such as fire fighters, police, or HAZMAT personnel, many times arrive at the site of an emergency situation without the ability to detect environmental hazards such as toxic industrial chemicals, chemical warfare agents, or radiation. Such inability may result in physical harm to the first responders and other responders that follow. Large quantities of toxic industrial chemicals may be present in populated areas: industrial sites, storage depots, transportation and distribution facilities, resulting in the potential for accidents such as the accidental release of methylisocyanate in Bhopal, India in 1984. Other toxic industrial chemicals, for example, include ammonia, chlorine, hydrogen chloride, and sulfuric acid. Chemical warfare agents are usually more lethal than toxic industrial chemicals. Nerve agents are the most common chemical warfare agents, such as the nerve agent Sarin that was used in the 1995 Tokyo subway gas attack. Other chemical warfare agents, for example, include Tabun, sulfur mustard, and hydrogen cyanide.  
         [0003]     Chemical warfare agents typically are medium to high volatility and therefore may be detected in the gas phase. Electronic monitors for chemical warfare agents are based on electronic detection using ion-mobility-spectrometry, photo-ionization and flame-ionization. These tools offer a broadband response with high levels of sensitivity, but most suffer from interference effects caused by what is often a highly complex chemical background mix at the scene, and most commercial tools exhibit high false-positive responses to contaminants. Furthermore, these devices are not designed to be wearable, and most tools, although handheld, are relatively bulky and fully engage the user, thereby detracting from other important duties.  
         [0004]     Known colorimetric methods for detecting such chemical and biological hazards include simple color-change badges generally having a life span of approximately 8 hours, to tubes providing quantitative data with high specificity, but both require the user to assess the color change to determine the hazard level. Furthermore, gas tubes are sensitive to physical abuse and are limited in some cases to only one or in other cases a few hazards requiring the user to know what type or types of hazards are suspected.  
         [0005]     Radiological threats have become more relevant with the so-called ‘dirty bomb’, which combines explosive blast with surreptitious ingredients of radionuclides such as Cs-137, a beta and gamma emitter. Radiological monitors (dosimeters) have been available for many years, mostly for occupational safety monitoring. Pager style, wearable units, having audio/visual alerts built-in are available for such monitoring. Also, a variety of miniature radiation detectors exist, such as small Geiger-Muller tubes, selective scintillation layers with photo-sensors, and silicon diodes. Probes can be attached to other types of monitors, covering any of the radiation species, but these monitors are at best hand-held, and must be maintained regularly. Recently, calorimetric badges that detect radiation have been developed; however, these require the user to constantly monitor its status.  
         [0006]     The idea of using interchangeable sensor elements for colorimeter detection has been used for water/soil testing, health monitoring, and a wide range of medical testing and analysis applications. However, known calorimeter systems employing interchangeable sensors are not capable of use in a wide range of colorimetric applications, particularly portable applications requiring a single lightweight calorimeter device. Many calorimeters require a PC, spectrometer, or other similar equipment to produce and/or process a colorimetric reagent. Operating these colorimeters is very difficult, requiring constant user interaction to complete the colorimetric detection process whenever a colorimeter measurement is made. These calorimeters require complex recalibration procedures, often involving multiple measurements using one or more sample reagents, each time a different sensor element is used.  
         [0007]     Furthermore, existing calorimetric sensor elements that are interchangeable have little or no capability to store reagent related data on the element, and therefore are inherently limited in use to a narrow range of calorimetric applications. Colorimeter devices used for water testing or urinanalysis can use a number of different test strips, each strip containing reagents targeting different substances. But these sensor elements would not be functional if a different set of reagents was deposited on the element. Any change in configuration to the sensor element would require an associated change to the calorimeter detection firmware.  
         [0008]     Some calorimetric, and non-colorimetric, systems employ interchangeable elements with embedded calibration data on the sensor element. But these devices have dedicated hardware to read the data using a process unrelated to that used to read the actual calorimetric data, therefore incurring significant increases in cost, size and overall complexity.  
         [0009]     Accordingly, it is desirable to provide a universal card that may be interchangeably used in a low cost, low power electronic device for detecting the presence of environmental agents and transmitting the results to the user and others without disrupting from the user&#39;s duties. 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 OF THE INVENTION  
       [0010]     An apparatus is provided for detecting an environmental agent. The apparatus, capable of being inserted into an electronic device having an imager and a processor, comprises a substrate; one or more calorimetric reagents positioned on the substrate; one or more reference colors, each associated with one of the one or more calorimetric reagents; and data bars positioned on the substrate depicting information about the one or more calorimetric reagents. When the apparatus is inserted in the electronic device, the imager is capable of detecting colors of the calorimetric reagents based upon the one or more reference colors and information from the data bars, the processor determining whether one or more environmental agents are present based upon colors changes of the colorimetric reagents.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]     The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and  
         [0012]      FIG. 1  is a cross sectional view of a first embodiment of the present invention;  
         [0013]      FIG. 2  is a top view taken along the line  2 - 2  of  FIG. 1 ;  
         [0014]      FIG. 3  is an isometric view of the embodiment of  FIG. 1  and an electronic device for imaging same;  
         [0015]      FIG. 4  is a top view of the first embodiment of the invention positioned in the electronic device;  
         [0016]      FIG. 5  is a top view of another embodiment of the present invention; and  
         [0017]      FIG. 6  is a block diagram of the embodiment of  FIG. 1  and the electronic device. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0018]     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 invention.  
         [0019]     Referring to  FIGS. 1 and 2 , the apparatus  10  includes colorimetric reagents  14  positioned on card  10 . The card may comprise any non-breakable material, such as glass, paper, or plastic. The colorimetric reagents  14  comprise a thin layer of a chemical that maintains a certain color in the absence of an environmental agent, but changes color when subjected to a specific agent. Examples of chemicals that could be used as calorimetric reagents include the following:  
         [0020]     The calorimetric reagent  14  comprising K 2 Pd(SO 3 ) 2  would turn from yellow to black when exposed to carbon monoxide (CO) in accordance with the equation: 
 
CO+K 2 Pd(SO 3 ) 2  yields K 2 (SO 3 ) 2 PdCO, 
 
where K 2 (SO 3 )PdCO yields CO 2 +SO 2 +Pd+K 2 SO 3 . 
 
         [0021]     The colorimetric reagent  14  comprising H 3 PO 4  and a pH indicator, for example bromophenol blue, would turn from yellow to blue when exposed to ammonia (NH3) in accordance with the equation: 
 
2NH 3 +H 3 PO 4  yields (NH 4 ) 2 PO 4 . 
 
         [0022]     Reference colors  16  are positioned on base  12 , each reference color  16  preferably adjacent a corresponding colorimetric reagent  14 . The reference color  16  may have substantially the same color as the original, unexposed calorimetric reagent or be set to a color corresponding to a specific level of accumulated exposure.  
         [0023]     Data bars  18  are positioned on the base  12 , and contain information about each colorimetric reagent  14 . Preferably, the data bars  18  containing information about a specific calorimetric reagent  14 , as well as the reference color  16 , are positioned next to that calorimetric reagent  14 . However, it should be understood that the data bars could be placed anywhere on the base  12 .  
         [0024]     The colorimetric reagents  14 , and optionally the reference colors  16  and data bars  18 , may be encapsulated in a material  20 , for example, paper, plastic, or thin metal, that may be removed by pulling on tab  22 . Some calorimetric reagents  14  may have a relative short life span, e.g., approximately 8 hours, in ambient air. The material  20  prevents this life span to begin only when the material  20  is removed, and further protects the colorimetric reagents  14 , reference colors  16 , and data bars  18 , from other damage.  
         [0025]     It should be understood that the calorimetric reagents  14 , reference colors  16 , and data bars  18  may take any format or position on the base  12 . For example, the colorimetric reagents  14  may be other than a circle and may be grouped together, separate from the reference colors  16  and data bars  18 . However, in the preferred embodiment, each colorimetric reagent  14  and an associated reference color  16  will be positioned adjacent to one another.  
         [0026]     Each corresponding calorimetric reagent  14  and reference color  16  optionally may be encompassed within a complimentary color  24  that enhances the detection of the color when imaged.  
         [0027]      FIG. 3  illustrates how the apparatus  10  may be inserted into an electronic device  30 .  FIG. 4  illustrates a top view of the electronic device  30 , which comprises a base  34  positioned within the housing  32 . The base  34  may comprise packaging, an integrated circuit board, or a semiconductor material and may include interface circuitry, a processor, etc., in a manner known to those skilled in the art. An imager  36  is positioned on the base for visually detecting the colors of the colorimetric reagents  14  and is electronically coupled to the processor within the base  12 . A lens  37  is positioned on the imager  36  for focusing light from the card  10  onto the imager  36 . The card  10  is shown as being inserted within the electronic device  30 . The card  10  is held in place by arms  38  and may be easily inserted therein and removed therefrom. An optional light source  40  is provided for directing light onto the colorimetric reagent dots. The light source provides a known spectrum that results in a more reliable determination of the colors of the calorimetric reagent dots than is provided by ambient light. A power source  42  is coupled to the base  34  (and thereby, the imager  36 ) and the light source  40  by connectors  44 , respectively. The power source  42  may be, for example, a battery or an AC adaptor.  
         [0028]     Referring to  FIG. 5 , an alternate placement of the optional light source  40  allows for light to pass through the apparatus  10  (which would be transparent in this embodiment) and through the colorimetric reagents  14  and reference colors  16 .  
         [0029]     Referring to  FIG. 6 , the card  10  (and colorimetric reagents  14  and reference colors  16 ) receive light from the light  40 , which is then reflected as colored light to the imager  36 . The data bars  18  also project a light pattern onto the imager  36 . The processor within the base  34  compares this light from the colorimetric reagents with that of the reference colors  16 , and based on the information gained from “reading” the data bars  18 , makes a determination whether an environmental component is present. The base  34  may be coupled to a display  50  for visually displaying information provided from the processor, an RF interface  52  for transmitting the information to others, and an alarm  54  that would audibly and/or visually alert the user.  
         [0030]     When a card  10  is inserted into the device  30 , the surface of the card  10  containing the calorimetric reagents  14 , reference colors  16 , and data bars  18  is positioned facing a miniature lens  37  which focuses light waves reflected from the card  10  surface onto the photodiode array of an imager  36  positioned underneath and concentric with the lens  37  assembly. The imager  36  can sample the light waves focused onto the photodiode array whenever an internal light source  40  is enabled. The light source  40  comprises a set of white LEDs, for example, which are positioned in a tight pattern around the perimeter of the lens assembly, and are also pointed directly at the card  10  surface.  
         [0031]     An embedded microcontroller initiates the imaging process by enabling the internal light source  40  to emit sufficient light directly at the card  10  surface. The light waves reflect off of the card  10  surface onto the lens  37 , and are focused onto the imager  36  photodiode array. After the light source  40  is enabled, the microcontroller instructs the imager  36  to begin sampling the photodiode array output changes, and the sampled image data is clocked out of the photodiode array serially in a stream of data bytes into the microcontroller for calorimetric detection processing. The microcontroller contains embedded firmware designed to collect and separate the incoming imaged data bytes for each colorimetric reagent  14  section and it&#39;s corresponding reference color  16  section. Each calorimetric reagent  14  and its reference areas are located such that the incoming stream of data bytes is ordered with groups of each reagent&#39;s image data adjacent to a corresponding group of reference data. Therefore, the microcontroller alternatively receives groups of colorimetric reagent image data and reference color data, each group providing a set of reagent data bytes that can be subtracted individually from image data bytes in a reference color data group, yielding a group of numbers equal to the difference in their magnitude. This resultant set of difference values is averaged to produce a single value that represents the current colorimetric state of the calorimetric reagent material. This value may be compared to a predefined threshold value indicated in the corresponding data bars, or a set of predefined threshold values to ultimately determine if an alert must be issued.  
         [0032]     Card  10  may be disposable, while the electronics of the device  30  may be reused on many occasions, thereby providing a cost advantage. The reference color  16  provides for an accurate on the spot determination of the “original” color of the colorimetric reagent  14 , eliminating the need to calibrate the device  30 . The data bars  18  provide information about the colorimetric reagents  14 , eliminating the need to program each device  30  with such information. Card  10  is a universal “smart” sensor, interchangeable with any card  10  incorporating the methods disclosed here, that enables colorimetric detection for a wide range of applications using a single, low cost, portable device.  
         [0033]     This card  10  embeds colorimetric reagent-related data which can be read concurrent with each reagent, avoiding the additional cost size, or complexity incurred by typical sensor designs using dedicated hardware to read the data separate from the actual reagent state.  
         [0034]     The reagent-related information provided eliminates the complex reassembly or recalibration procedures required by most calorimeter products employing interchangeable elements. A user doesn&#39;t need to perform any setup, reconfiguration, or recalibration of the calorimeter instrument whenever a different card  10  is used.  
         [0035]     Card  10  can be exchanged quickly, allowing a user to resume active sensing operation immediately—an important factor in sensing applications involving hazardous substances, or where easy-to-use, portable colorimetric detection devices are needed. As new calorimetric reagents are developed, or different combinations of new or existing reagents are required, the card  10  design will accommodate these new configurations without requiring changes to embedded firmware in the electronic device  30 . The card  10  design allows for multiple colorimetric reagents to be deposited on the card  10  surface, independently positioned with regard to the reagent species. Each colorimetric reagent  14  deposition contains embedded data which can be read concurrent with the reagent color state. Although each calorimetric reagent  14  occupies it&#39;s own section on the card  10 , the physical position of each colorimetric reagent  14  is not used when the element surface is “imaged” to produce blocks of image data containing both the colorimetric state of each calorimetric reagent  14  and the embedded information. In general, the data embedded in the data bars  18  preferably would include the following: 
    1) specie information identifies the specific substance being detected,     2) parametric information identifies reference color(s) defining the detection thresholds, and     3) expiration date information.    
 
         [0039]     The specie information identifies the substance targeted by each colorimetric reagent  14 . The parametric data is comprised of element surface areas specifically colored to match a reagent&#39;s color state at important detection thresholds. This idea embeds this reference color data together with each reagent to enable both the reference and reagent color state to be “imaged” simultaneously. Every time a colorimetric reagent  14  is imaged, all corresponding reference color state(s) are imaged concurrently, insuring that any errors introduced during the imaging process (due to changes in lighting, focus, object distance, etc . . . ) are “common” to both the reagent and reference color state data. This “common-mode” noise component is automatically eliminated during the detection processing that follows because only differences in the reference and agent color states are used to determine the actual reagent color state.  
         [0040]     This provides a universally interchangeable sensor element  14  that embeds calorimetric reagent data, such that the calorimetric reagent  14  and the data can be read concurrently with a single image processing-based platform to provide calorimetric detection applicable to a broad range of sensing applications. As new colorimetric reagents  14  become available, this design can accommodate these new colorimetric reagents  14  without requiring redesign or firmware updates to the electronic device  30 . Furthermore, complex instrument disassembly or recalibration procedures are eliminated during card  10  replacement, allowing for continuous sensing operation without limiting the range of colorimetric applications. Finally, the card  10  provides calorimetric measurement results for each reagent in a differential format which inherently rejects common-mode errors, and consequently, enhances the sensitivity of the calorimeter.  
         [0041]     While at least one exemplary embodiment 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 the exemplary embodiment or 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 an exemplary embodiment of the invention, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the invention as set forth in the appended claims.