Abstract:
A portable, tabletop fluid sampling device simplifies spectral analysis to produce an accurate but inexpensive chromatic fingerprint for fluid samples. In one embodiment, the sampling device uses an array of variable wavelength LED emitters and photodiode detectors to measure Rayleigh scattering of electromagnetic energy from the fluid sample contained in a cuvette. Either the fluid itself, or particles suspended in the fluid can then be identified by performing spectral pattern matching to compare results of a spectral scan against a library of known spectra. A wide range of applications include substance identification, security screening, authentication, quality control, and medical diagnostics.

Description:
BACKGROUND 
       [0001]    1. Field 
         [0002]    This disclosure generally relates to evaluation systems, and more particularly to systems that evaluate characteristics of substances using electromagnetic energy. 
         [0003]    2. Description of the Related Art 
         [0004]    Various systems employ spectral analysis returned from a sample of a substance to analyze the sample and/or recognize the substance. 
         [0005]    For example, U.S. Pat. No. 8,076,630 describes systems and methods of evaluating objects using electromagnetic energy. In particular, U.S. Pat. No. 8,076,630 teaches a system for evaluating subject objects, the system which includes at least one physical source operable to emit electromagnetic energy and driver electronics drivingly coupled to at least one physical source. The driver electronics drive at least one physical source as a number of logical sources, using an electromagnetic forcing function where the number of logical sources is greater than the number of physical sources. In addition, the system includes a sensor to receive an electromagnetic response from at least a portion of an evaluation object illuminated by one or more physical sources operated as logical sources, and convert the electromagnetic response to a test response signal indicative of the electromagnetic response of the evaluation object. 
         [0006]    Also for example, U.S. Pat. No. 7,996,173 describes methods, apparatus and articles to facilitate distributed evaluation of objects using electromagnetic energy. In particular, U.S. Pat. No. 7,996,173 teaches that objects such as manufactured goods or articles, works of art, media such as identification documents, legal documents, financial instruments, transaction cards, other documents, and/or biological tissue are sampled via sequential illumination in various bands of the electromagnetic spectrum, and a test response to the illumination is analyzed with respect to reference responses of reference objects. U.S. Pat. No. 7,996,173 teaches that the sequence may be varied. For instance, the sequence may define an activation order, a drive level and/or temperature for operating one or more sources. Illumination may be in visible, infrared, ultraviolet, or other portions of the electromagnetic spectrum. U.S. Pat. No. 7,996,173 further teaches that elements of the evaluation system may be remote from one another, for example communicatively coupled via a network. 
         [0007]    As a further example, U.S. Pat. No. 8,081,304 describes the use of spectral information in process control and/or quality control of goods and articles. In particular, U.S. Pat. No. 8,081,304 describes the use of spectral information in process control and/or quality control of media, for example financial instruments, identity documents, legal documents, medical documents, financial transaction cards, and/or other media, fluids for example lubricants, fuels, coolants, or other materials that flow, and in machinery, for example vehicles, motors, generators, compressors, presses, drills and/or supply systems. U.S. Pat. No. 8,081,304 further describes the use of spectral information in identifying biological tissue and/or facilitating diagnosis based on biological tissue. 
         [0008]    The above described patents are only representative. 
       BRIEF SUMMARY 
       [0009]    It may be useful to analyze fluids, in particular, to determine various physical characteristics of the fluids and/or to recognize the fluid as carrying or not carrying a specific type of substance. In order to reliably analyze and/or recognize a fluid or a substance within the fluid, it may be useful to sample the fluid at a relatively large number of distinct wavelengths or bands of wavelengths of electromagnetic energy. The wavelengths may for example include some or all wavelengths in an optical portion of the electromagnetic spectrum, from near-infrared (N-IR) to near-ultraviolet (N-UV), inclusive, including a visible portion that is visually perceptible to humans. Accurately performing such analysis or recognition typically requires a relatively large number of distinct sources or emitters, e.g., solid-state sources of electromagnetic energy such as light emitting diodes (LEDs), each operable to emit electromagnetic energy in a respective range or band of wavelengths which may or may not partially overlap with one another. 
         [0010]    To achieve a high degree of reliability it may be advantageous to perform calibration. Calibration can address issues raised by variations in source performance, for example variations in emitter wavelength output due to age, changes in temperature, or even in manufacturing tolerances (e.g., from batch to batch from a given emitter manufacturer). However, to be effective calibration will typically need to be performed automatically, preferably with little to no user or operator interaction. Also, to be effective calibration with respect to sources or emitters should employ calibration targets or samples with known characteristics (e.g., spectral characteristics) which are stable and do not vary over time. 
         [0011]    Providing for automatic calibration may enhance the accuracy of sampling devices. Providing for automatic calibration in a compact form factor may further allow for small, portable sampling devices, which are highly accurate. 
         [0012]    Scattering is a physical process in which some forms of electromagnetic energy deviate from a straight path or trajectory due to localized non-uniformities in a medium through which the electromagnetic energy passes. As commonly used, this also includes deviation of reflected electromagnetic energy from an angle predicted by the law of reflection. Reflections that undergo scattering are often called diffuse reflections, while unscattered reflections are called specular (e.g., mirror-like) reflections. 
         [0013]    Electromagnetic scattering mechanisms include, for example, Rayleigh scattering and Raman scattering. In Rayleigh scattering most photons are elastically scattered such that the scattered photons have the same kinetic energy, and therefore the same wavelength, as the incident photons. In Raman scattering, photons are scattered by excitation, so that the scattered photons have a frequency that is different from, and usually lower than, that of the incident photons. For any given sample both mechanisms will typically apply, with Raman scattering making up a smaller fraction of the total scattering. Raman scattering is particularly useful in analyzing composition of liquids, gases and solids. 
         [0014]    Lambertian reflectance characterizes an ideal diffusely reflecting surface. An apparent brightness of such an ideal diffusely reflecting surface is the same regardless of angle of view. Technically, the luminance of a surface is isotropic, and luminous intensity obeys Lambert&#39;s cosine law. Lambertian reflection from polished (i.e., glossy or non-matte) surfaces is typically accompanied by specular reflection. The luminance of a polished or glossy surface is largest when viewed at a perfect reflection direction, for example, normal to the surface (i.e., where a direction of the reflected light is a reflection of the direction of the incident light in the surface). The luminance falls off sharply as direction (i.e., angle) changes. 
         [0015]    An undisturbed surface of a liquid exhibits specular (mirror-like) reflection. To achieve a high degree of accuracy, in some implementations it may be advantageous to eliminate specular reflection or at least allow discrimination between scattered and specular reflection. Such reflection may be from a sample or specimen itself, a surface on which the sample or specimen resides, or even a component of a sampling device, for instance a protective window or lens cover. To achieve a high degree of accuracy, in some implementations it may be advantageous to separate specular reflection from diffuse reflection, detecting each separately. 
         [0016]    Sampling devices employing automatic calibration and/or separation of specular reflection may be effective employed in the object analysis, evaluation or identification to various applications, for example: manufacturing process control, quality assurance, media authentication, biological tissue recognition, identification, verification, authentication, classification, and/or diagnostics. 
         [0017]    A sampling device may be summarized as including a housing; a sample chamber in the housing, the sample chamber sized and dimensioned to receive a sample cuvette at least partially therein, the sample chamber having at least one opaque wall and at least a first aperture and a second aperture positioned at least partially across at least a portion of the sample chamber from the first aperture, the first and the second aperture transmissive of electromagnetic energy of at least some wavelengths in an optical portion of the electromagnetic spectrum; a plurality of emitters received in the housing, each of the emitters selectively operable to emit electromagnetic energy in a respective range of wavelengths toward and through the first aperture of the sample chamber, the ranges of wavelengths of at least some of the emitters different from the ranges of wavelengths of others of the emitters; at least one primary sampling sensor positioned to receive electromagnetic energy emitting from the sample chamber via the second aperture; and at least one calibration sensor positioned to receive electromagnetic energy emitted by at least one of the emitters, substantially free of electromagnetic energy emitting, if any, from the sample chamber. 
         [0018]    The sampling device wherein there may be formed a slit in a calibration printed circuit board (PCBA) opposed to the emitters, and the at least one calibration sensor may include at least a first calibration sensor positioned to one side of the slit and at least a second calibration sensor positioned to another side of the slit, the other side of the slit disposed across the slit from the first side of the slit. The emitters may all be aligned with the first aperture. The at least one calibration sensor may be positioned at least adjacent a first portion of the sample chamber opposed to the emitters. The emitters may be carried by an emitter circuit board, the emitter circuit board spaced from the sample chamber opposed to the first aperture. At least one of the primary sampling sensors may be carried by a direct sensor circuit board, the direct sensor circuit board spaced from the sample chamber opposed to the second aperture. The sample chamber may include a third aperture, the third aperture positioned at least partially across the sampling chamber from both the first and the second apertures, and the at least one primary sampling sensor may include at least a first primary sampling sensor positioned to receive electromagnetic energy emitting from the sampling chamber via the second aperture and at least a second primary sampling sensor positioned to receive electromagnetic energy emitting from the sampling chamber via the third aperture. The second aperture may be diametrically opposed across the sample chamber from the first aperture and the third aperture may be non-collinear with an optical axis that extends between the first and the second apertures. The third aperture may be positioned along an axis perpendicular to the optical axis that extends between the first and the second apertures. The emitters may be carried by an emitter circuit board, the emitter circuit board spaced from the sample chamber opposed to the first aperture, at least the first primary sampling sensors may be carried by a direct sensor circuit board, the direct sensor circuit board spaced from the sample chamber opposed to the second aperture, and at least the second primary sampling sensors may be carried by an indirect sensor circuit board, the indirect sensor circuit board spaced from the sample chamber opposed to the third aperture to capture electromagnetic energy scattered from the sample chamber. The sampling device may further include a biasing member such as, for example, a spring that biases at least the sample cuvette outwardly from the housing. The respective ranges of wavelengths of at least two of the emitters may at least partially overlap. The sampling device may further include the sample cuvette sized and dimensioned to be at least partially received by the sample chamber, at least a portion of the sample cuvette transmissive to at least some of the wavelengths of electromagnetic energy emitted by the emitters. The optical portion of the electromagnetic spectrum may extend from near-infrared through near-ultraviolet. The sampling device may further include at least one port providing flow through fluid communication with the cuvette. The sampling device may further include at least one control subsystem communicatively coupled to the emitters, the primary sampling sensors; and the calibration sensors; and at least one temperature sensor communicatively coupled to the at least one control subsystem, wherein the at least one control subsystem controls operation based at least in part on information from both the calibration sensors and the at least one temperature sensor. The at least one control subsystem may calibrate an output value based at least in part on information from both the calibration sensors and the at least one temperature sensor. The at least one control subsystem may calibrate a drive signal supplied to at least one of the emitters based at least in part on information from both the calibration sensors and the at least one temperature sensor. 
         [0019]    A sampling device may be summarized as including a housing; a sample chamber in the housing, the sample chamber sized and dimensioned to receive a sample cuvette at least partially therein, the sample chamber having at least one opaque wall and at least a first aperture, a second aperture positioned at least partially across at least a portion of the sample chamber from the first aperture, and a third aperture, the third aperture positioned at least partially across the sampling chamber from both the first and the second apertures, the first, the second, and the third apertures transmissive of electromagnetic energy of at least some wavelengths in an optical portion of the electromagnetic spectrum; a plurality of emitters received in the housing, each of the emitters selectively operable to emit electromagnetic energy in a respective range of wavelengths toward and through the first aperture of the sample chamber, the ranges of wavelengths of at least some of the emitters different from the ranges of wavelengths of others of the emitters; at least one direct primary sampling sensor positioned to receive electromagnetic energy emitting from the sampling chamber via the second aperture and not by the first or the third apertures; and at least one indirect primary sampling sensor positioned to receive electromagnetic energy emitting from the sampling chamber via the third aperture and not by the first or the second apertures. 
         [0020]    The second aperture may be diametrically opposed across the sample chamber from the first aperture. The third aperture may be non-collinear with an optical axis that extends between the first and the second apertures. The third aperture may be perpendicular to an optical axis that extends between the first and the second apertures. The emitters may be carried by an emitter circuit board, the emitter circuit board spaced from the sample chamber opposed to the first aperture, at least the first primary sampling sensor may be carried by a direct sensor circuit board, the direct sensor circuit board spaced from the sample chamber opposed to the second aperture, and at least the second primary sampling sensor may be carried by an indirect sensor circuit board, the indirect sensor circuit board spaced from the sample chamber opposed to the third aperture to capture electromagnetic energy scattered from the sample chamber. The sampling device may further include at least one calibration sensor positioned to receive electromagnetic energy emitted by at least one of the emitters, substantially free of electromagnetic energy emitting, if any, from the sampling chamber. The sampling device may further include at least one control subsystem communicatively coupled to the emitters, the primary sampling sensors; and the calibration sensors; and at least one temperature sensor communicatively coupled to the at least one control subsystem, wherein the at least one control subsystem controls operation based at least in part on information from both the calibration sensors and the at least one temperature sensor. The at least one control subsystem may calibrate an output value based at least in part on information from both the calibration sensors and the at least one temperature sensor. The sampling device may further include a biasing member that biases at least the sample cuvette outwardly from the housing. The respective range of wavelengths of at least two of the emitters may at least partially overlap. The sampling device may further include the sample cuvette sized and dimensioned to be at least partially received by the sample chamber, at least a portion of the sample cuvette transmissive to at least some of the wavelengths of electromagnetic energy emitted by the emitters. The optical portion of the electromagnetic spectrum may extend from near-infrared through near-ultraviolet. The sampling device may further include at least one port providing flow through fluid communication with the cuvette. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) 
         [0021]    In the drawings, identical reference numbers identify similar elements or acts. The sizes and relative positions of elements in the drawings are not necessarily drawn to scale. For example, the shapes of various elements and angles are not drawn to scale, and some of these elements are arbitrarily enlarged and positioned to improve drawing legibility. Further, the particular shapes of the elements as drawn, are not intended to convey any information regarding the actual shape of the particular elements, and have been solely selected for ease of recognition in the drawings. 
           [0022]      FIG. 1  is an isometric view of the exterior of a fluid sampling device with a hinged lid in the fully open position, according to one illustrated embodiment. 
           [0023]      FIG. 2  is a pictorial perspective view of the exterior of a fluid sampling device with a hinged lid in the closed position, according to one illustrated embodiment. 
           [0024]      FIG. 3  is a top plan view of the exterior of a fluid sampling device according to one illustrated embodiment. 
           [0025]      FIG. 4  is a bottom plan view of the exterior of a fluid sampling device according to one illustrated embodiment. 
           [0026]      FIG. 5  is a side elevation view of the exterior of a fluid sampling device, in which a communications port is shown, according to one illustrated embodiment. 
           [0027]      FIG. 6  is a top perspective view of a parts assembly shown removed from the housing of a fluid sampling device, according to one illustrated embodiment. 
           [0028]      FIG. 7  is a top plan view of the parts assembly of the fluid sampling device of  FIG. 6  shown relative to the housing, in which propagation paths of incident and scattered electromagnetic energy are indicated by a ray diagram. 
           [0029]      FIG. 8  is a pictorial perspective view of a sample chamber within a fluid sampling device, according to one illustrated embodiment. 
           [0030]      FIG. 9  is an isometric view of the parts assembly of  FIG. 6 , shown relative to the sample cuvette. 
           [0031]      FIG. 10  is an isometric view of the parts assembly shown in  FIG. 9 , relative to the sample chamber, according to one illustrated embodiment. 
           [0032]      FIG. 11  is an isometric view of the parts assembly of the fluid sampling device of  FIG. 6 , shown relative to the sample cuvette, in which emitter chips are shown mounted on the emitter printed circuit board assembly and sensor chips are shown on the backplane. 
           [0033]      FIG. 12  is an interior side elevation view of one embodiment of a fluid sampling device, in which propagation paths of incident and scattered electromagnetic energy are indicated. 
           [0034]      FIG. 13  is an isometric view of a sampling system that includes one or more fluid sampling devices and one or more processor-based devices to which the fluid sampling devices are communicatively coupled, according to one illustrated embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0035]    In the following description, certain specific details are set forth in order to provide a thorough understanding of various disclosed embodiments. However, one skilled in the relevant art will recognize that embodiments may be practiced without one or more of these specific details, or with other methods, components, materials, etc. In other instances, well-known structures associated with computing systems, networks, servers, microprocessors, memories, buses, sources of electromagnetic energy, and/or detectors or sensors have not been shown or described in detail to avoid unnecessarily obscuring descriptions of the embodiments. 
         [0036]    Unless the context requires otherwise, throughout the specification and claims which follow, the word “comprise” and variations thereof, such as, “comprises” and “comprising” are to be construed in an open, inclusive sense, that is as “including, but not limited to.” 
         [0037]    Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. 
         [0038]    As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the content clearly dictates otherwise. It should also be noted that the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise. 
         [0039]    The headings and Abstract of the Disclosure provided herein are for convenience only and do not interpret the scope or meaning of the embodiments. 
         [0040]    The ability to recognize, identify, verify, authenticate and/or classify objects has numerous commercial applications. 
         [0041]    It may be useful to determine analyze characteristics of a sample or specimen being evaluated. For example, it may be useful to determine whether a sample or specimen being evaluated is identical or similar to a previously evaluated sample or specimen, for instance a reference sample or specimen. Also for example, it may be useful to determine if a sample or specimen is identical to a previously evaluated sample or specimen. 
         [0042]    Referring to  FIGS. 1 and 2 , a fluid sample or specimen analysis or evaluation device  100  is shown according to one illustrated embodiment, referred to herein simply as sampling device  100 . Types of fluids that can be accommodated by the sampling device  100  include liquids, and highly viscous materials such as gels, slurries, pastes, and the like. Liquids include pure liquids and liquids containing particulates such as, for example, colloidal suspensions. Some examples of the sampling device  100  can accommodate other types of fluid samples such as aerosols or other suspensions of liquid droplets or solid particles in a gas (e.g., sprays). Other examples of the sampling device  100  can include gases themselves (pressurized or un-pressurized (e.g., air, or atmospheric samples). However, because the sampling device  100  may be used more often to analyze liquids, the sampling device  100  can be referred to as a liquid scanner. 
         [0043]    As discussed in detail below, the sampling device  100  is operable to sequentially illuminate a fluid sample with a number of bands of electromagnetic energy. The sampling device  100  is also operable to detect, measure or otherwise capture electromagnetic energy reflected, emitted, fluoresced, refracted, diffracted or otherwise transmitted, or otherwise returned from the fluid sample in response to the illumination. As used herein and in the claims, the terms illuminate, illuminates, illumination, and variations of such terms mean to expose to or reveal by the use of electromagnetic energy or electromagnetic energy, whether in the visible portion of the electromagnetic spectrum, the optical portion (e.g., visible, near-infrared, near-ultraviolet), or other portions (e.g., far-infrared, far-ultraviolet, microwave, X-ray, etc.). 
         [0044]    The sampling device  100  includes a housing  102  which, in the illustrated embodiment, includes a tubular (e.g., cylindrical) main body housing portion  102   a , a sample chamber  102   b  in the main body housing portion  102   a , and a cap  102   c  having a top surface  104 . The housing  102  may, for example, be sized and dimensioned as a portable tabletop unit that can be hand carried from one location to another. Furthermore, such a table top unit is intended to be accessible and affordable to a wider range of users than are existing laboratory-based models. 
         [0045]    The main housing portion  102   a  has a housing base  106   a  and a housing top  106   b  opposite the housing base  106   a . The main housing portion  102   a  has a side wall  108  surrounding the sample chamber  102   b  which is adjacent to an exterior surface of the main housing portion  102   a . The top end  106   b  can be exposed by opening exemplary hinged lid  117  to provide selective access to the sample chamber  102   b . The main housing portion  102   a  may be comprised of any of a large variety of materials, for example ABS plastic, other plastics, metals (e.g., aluminum) and/or composite materials (e.g., carbon fiber impregnated resin). The main body housing portion  102   a  may be sized and dimensioned to be easily held and operated by a person using a single hand. While illustrated as a cylinder, the main body housing portion  102   a  may take any variety of shapes. 
         [0046]    The sampling device  100  may also include one or more function buttons  110  which are operable from an exterior of the sampling device  100 , for example, from the cap  102   c . The function buttons  110  may take any of a large variety of forms, other than push-buttons, (e.g., slideable switches, rotatable selectors, and the like). For example, a contact or slideable switch may be actuatable via a window, slot or other aperture in the housing  102 . Additionally or alternatively, a touch sensitive switch may be employed, for instance an inductive or a capacitive switch. The function buttons  110  may be responsive to actuation to send a signal, or otherwise cause the sampling device to execute a sampling operation. As discussed in detail below, the sampling operation may be preceded by a calibration operation. 
         [0047]    The sampling device  100  may further include one or more visual indicators (e.g., light emitting diodes or LEDs, two shown collectively referenced as  112 ), shown in  FIGS. 1 ,  2  as located on an upper surface  104  of the cap  102   c . The visual indicators  112  may indicate a status or mode of the sampling device (e.g., “ready” or “power on”), for instance via different colors (e.g., green, red, amber) and or patterns (e.g., flashes). Or, one or more light communicative paths (e.g., optical fiber or light pipes) may communicatively couple light to the visual indicators  112 . Additionally or alternatively, visual indicators  112  may be located anywhere on the housing  102 , or underneath a window (not shown) mounted anywhere on the surface of the housing  102 . 
         [0048]    The sample chamber  102   b  is sized and dimensioned to at least partially receive, as shown in  FIG. 1 , a specimen container referred to as a sample cuvette  114 . The sample cuvette  114  may be made of any of a large variety of materials transmissive (i.e., transparent or at least translucent) to at least those wavelengths of electromagnetic energy (e.g., UV) which are used in the analysis or evaluation of a sample or specimen. Such materials may include, for example, silica (i.e., fused quartz) or a cyclic polyolefin commercially available from Zeon Chemicals of Louisville, Ky. under the trademark Zeonex®, for example having minimal absorption characteristics for wavelengths between approximately 330 nm and extending to or beyond approximately 1,200 nm. Material transparency may vary with the choice of wavelengths used for illumination. In addition, containment of different fluids may require different materials. A plurality of different cuvette types may therefore be accommodated by the sampling device  100 . While illustrated as a square cylindrical tube, the sample cuvette  114  and sample chamber  102   b  may take any variety of shapes. An advantage of the square cylindrical tube is the avoidance of focusing, refracting, or diffracting certain electromagnetic wavelengths. The sampling device  100  can further include a port providing flow through fluid communication with the sample cuvette  114 . 
         [0049]    The sample cuvette  114  has a removable cuvette lid  116  that need not be transparent. The cuvette lid  116  is desirably made of, or includes a material such as rubber, silicone, or another similar elastic material. The cuvette lid  116  can thus be capable of forming a seal against the sample cuvette  114  to prevent leakage of the fluid sample. 
         [0050]    The cap  102   c  can also include an access panel such as a hinged lid  117  that opens to allow access for an operator to load the sample cuvette  114  into the sample chamber  102   b . Alternatively, the access panel could take the form of a sliding cover, a fully removable cover, or any number of other lid designs. 
         [0051]    The exemplary hinged lid  117  is shown in  FIG. 1  in an open position, and in  FIG. 2  in a closed position. The hinged lid  117  can include a stabilizing feature  118  that helps to hold the sample cuvette  114  in a fixed position. The hinged lid  117  can further include a latch  120  that holds the hinged lid  117  securely closed during a sample analysis run. The securing engagement may be selectively releasable under a moderate application of pulling force or tension on the hinged lid  117 . Additionally or alternatively, the hinged lid  117  can be released by an operator action such as, for example, pressing one or both of the function buttons  110 . 
         [0052]    As shown in  FIG. 2 , a finger indentation  200  can be provided in the top surface of the hinged lid  117  to facilitate selective opening and/or secure closure by applying pressure directly over the latch  120 . The hinged lid  117  can be coupled to the sample cuvette  114  such that when the hinged lid  117  is closed, the sample cuvette  114  is held down in a fixed position within the sample chamber  102   b . When the hinged lid  117  is in an open position, the sample cuvette  114  can be automatically released by a biasing member (e.g., spring) so that the sample cuvette  114  pops up out of the sample chamber  102   b  for ease of removal. While  FIGS. 1 and 2  indicate certain shapes and/or dimensions (e.g., a cylindrical housing) which may be suitable for some embodiments, the sampling device  100  may employ other shapes and/or dimensions. Thus, the specified shapes and/or dimensions should not be considered limiting.  FIG. 3  presents a view  300  of the housing cap  102   c , showing a pair of hinges  302  about which the hinged lid  117  pivots. In one embodiment, the hinges  302  are located near the perimeter of the cap  102   c . It is noted that any number of alternative lid configurations can be substituted for the hinged lid  117  shown. 
         [0053]      FIG. 4  depicts a view  400  of the housing  102 , showing a plurality of feet  402   a ,  402   b ,  402   c , and  402   d , (four shown, collectively  402 ) on which the sampling device  100  can rest on a table top or desk top, for example. Also shown in  FIG. 4  is a pair of screws  404   a  and  404   b  (two shown, collectively  404 ) and a drain hole  406 . The drain hole  406  can prevent any liquid that may escape both the sample cuvette  114  and the sample chamber  102   b  from accumulating inside the housing  102 . 
         [0054]      FIG. 5  shows a view  500  of the back of the sampling device  100 , in which is shown a panel  502  surrounding a cable receptacle  504 . The panel  502  may be a removable access panel. While the cable receptacle  504  is pictured as a USB port it is not so limited. One or more other types of communications ports and/or power supply connections, or combinations thereof, may be provided in conjunction with the panel  502 . Such connections may provide pathways for power delivery and uni-directional or bi-directional data flow to support the functions of the sampling device  100 . Alternatively, or in addition, power and/or data connections to the sampling device  100  can be partly or fully wireless, thereby allowing data upload to a Web site via the Internet, for example. Instructions may also be received by the sampling device via the cable receptacle  504  or via a wireless connection. 
         [0055]      FIG. 6  shows a view  600  of internal parts within the sampling device  100  relative to the sample cuvette  114 . In the center is shown the top surface of the cuvette lid  116 . Inside the illustrated sampling device  100  are shown four printed circuit board assemblies (PCBAs): a transducer PCBA  602 , a calibrator PCBA  604 , a direct sensor PCBA  606 , and a backplane PCBA  608 , which also serves as an indirect sensor PCBA. In the embodiment shown, the PCBAs  602 ,  604 , and  606  are oriented substantially parallel to one another and substantially perpendicular to the backplane PCBA  608 , to which they connect. This orientation of the PCBAs provides a rigid structure that helps to direct the electromagnetic energy path. As illustrated, the backplane PCBA  608  may be sized and dimensioned to be securely received in housing  102 , for example engaging an inner periphery of the housing base  106   a , an inner periphery of the side wall  108 , or other attachment structures. Engagement may be via a press fit or via some coupling structure such as a detent structure, or a clip as shown below in  FIG. 12  to secure the PCBAs  602 ,  604 , and  606 . 
         [0056]    The PCBAs  602 ,  604 ,  606 , and  608  may comprise any of a large variety of materials, for example plastics metals, or composite materials. The PCBAs are typically opaque or substantially opaque, at least to electromagnetic energy that is employed in the analysis or evaluation of the samples or specimens. The PCBAs may, for example, be painted black, coated black, or may include black pigments. 
         [0057]    According to one embodiment, the function buttons  110  and visual indicators  112  are shown mounted to the top of the transducer PCBA  602 . The function buttons  110  are further shown attached to function button support plates  610  via function button fasteners  612 . The function button support plates  610  are coupled to the transducer PCBA  602  by function button coupling pins  614  that are through-hole mounted to the transducer PCBA  602 . Electrical connections from the function buttons  110  are also coupled to internal electronic and/or electrical components via the transducer PCBA  602 . Similarly, the visual indicators  112  are attached to indicator support plates  616 , and the indicator support plates  616  are coupled to the transducer PCBA  602  via indicator coupling pins  618 . Other form factors for the function buttons  110 , visual indicators  112 , and associated connections, or an alternative user interface can be substituted for those shown. 
         [0058]    As explained in more detail below, the transducer PCBA  602  includes a plurality of transducers, typically in the form of a plurality of emitters (seven shown, collectively  634 ). The calibrator PCBA  604  includes one or more calibration detectors or sensors (four shown, collectively  636 ). The direct sensor PCBA  606  includes one or more first primary sampling detectors or sensors (four shown, collectively  638 ). Also as explained in more detail below, the backplane PCBA  608  includes one or more second primary sampling detector(s) or sensor(s) (four shown, collectively  640 ), and various other electrical and electronic components (collectively  642 ) to control operation of the sampling device  100  and/or communications therefrom. The transducer PCBA  602 , the calibrator PCBA  604 , and the direct sensor PCBA  606  each include a respective coupler or connector  644   a ,  644   b , and  644   c , respectively, to communicatively couple electronic and/or electrical components or circuits of the each of the PCBAs  602 ,  604 , and  606  with the components or circuits of the backplane PCBA  608 . Accordingly, the backplane PCBA  608  can be configured with a plurality of sockets for receiving the connectors  644   a ,  644   b , and  644   c . Connectors  644   a ,  644   b , and  644   c  may be slot connectors having a slot sized and dimensioned to mate with a coupler of the transducer PCBA  602 , for instance an edge or tab. Each of the couplers or connectors  644   a ,  644   b , and  644   c  typically carry a variety of electrical contacts, although other signal transfer structures (e.g., optical fiber) can be employed. 
         [0059]    Power can also be supplied to each of the PCBAs  602 ,  604 , and  606  through the connectors  644   a ,  644   b , and  644   c . A power source (not shown) may take the form of a portable power source, for example one or more batteries, fuel cells, and/or super- or ultra-capacitors. Additionally, or alternatively, the power source may take the form of a fixed power source, such as a cable plugged into a port of a computer (e.g., USB cable) or a conventional electrical receptacle (e.g., wall outlet). 
         [0060]    The backplane PCBA  608  may, for example, optionally include a control subsystem  646  implemented as one or more integrated circuit chips attached to the PCBA  608 . Alternatively, the sampling device  100  may be coupled to an external control system, for example one or more programmed general purpose or special purpose computers or computer systems. 
         [0061]    The control subsystem  646  may, for example, be coupled to a central communications port  647  (e.g., Universal Serial Bus (USB) or mini-USB compliant female connector) as shown in  FIG. 6 . The central communications port  647  may be accessible from the exterior of the housing  102 , for example via the cable receptacle  504  and the removable access panel  502  in the surface of the housing  102 . While illustrated as a hardwired communication port  647  (e.g., a USB port), the sampling device  100  may include other types of communications ports or devices, for instance an infrared transceiver, or an RF transceiver (e.g., BLUETOOTH® transceiver). Such may allow the transmission of data, instructions and/or results, to or from the sampling device  100 . 
         [0062]    The control subsystem  646  may also include one or more controllers  648 , for example, one or more microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), programmable gate arrays (PGA), programmable logic controllers (PLCs), or other logic executing device. The control subsystem may include one or more non-transitory computer- or processor-readable media, for example one or more memories  650  such as read only memory (ROM)  650   a , or Flash memory  650   b  and random access memory (RAM)  650   c . One or more buses (not shown) may couple the ROM  650   a  and RAM  650   c  to the controller  648 . The buses may take a variety of forms including an instruction bus, data bus, other communications bus and/or power bus. A nonvolatile ROM and/or Flash memory  650   b  may store instructions and/or data for controlling the sampling device  100 . The volatile RAM  650   c  may store instructions and/or data for use during operation of the sampling device  100 . 
         [0063]    The optional controller  648  can employ instructions and or data from the ROM/Flash  650   b  and RAM  650   c  in controlling operation of the sampling device  100 . For example, the controller  648  operates the emitters  634  in one or more sequences. The sequences determine an order in which the emitters  634  are turned ON and OFF. The sequences may also indicate an ordered pattern of drive levels (e.g., current levels, voltage levels, duty cycles) for the emitters  634 . Thus, for example, a controller  648  may cause the application of different drive levels to respective ones of the emitters  634  to cause the emitters  634  to emit in distinct bands of the electromagnetic spectrum. Thus, the ranges of wavelengths of some of the emitters can be different from the ranges of wavelengths of others of the emitters. 
         [0064]    The controller  648  may process information generated by the primary sampling detector(s) or sensor(s)  638 ,  640 , which is indicative of the response by at least a portion of a sample or specimen to illumination by the emitters  634 . The information at any given time may be indicative of the response by the sample or specimen to illumination by one or more of the emitters  634 . Thus, the information over a period of time may be indicative of the responses by the sample or specimen to sequential illumination by each of a plurality of the emitters  634 , where each of the emission spectra of each of the emitters  634  has a different center, bandwidth and/or other more complex differences in spectral content, such as those described above (e.g., width of the band, the skew of the distribution, the kurtosis, etc.). The control subsystem  646  may optionally include a buffer (not shown) to buffer information received from the primary sampling detector(s) or sensor(s). The control subsystem  646  may further optionally include an analog to digital converter (ADC) (not shown) and/or digital to analog converter (DAC) (not shown). An ADC may, for example, be used for converting analog photodiode responses into digital data for further analysis and/or transmission. A DAC may, for example, be used for converting digital computer or controller commands into analog LED current levels. The control subsystem may additionally or alternatively optionally include an analog signal processor, which may be particularly useful where the sensor takes the form of one or more photodiodes. 
         [0065]    The control subsystem  646  may include a user interface including one or more user interface devices. For example, the control subsystem  646  may include one or more speakers or microphones (not shown). Also for example, the control subsystem  646  may include and/or one or more visual indicators, such as one or more LEDs, liquid crystal displays (LCD), or other visual indicators, which could include visual indicators  112 . The LCD may, for example, take the form of a touch sensitive LCD, which displays a graphical user interface, operable by the user of the sampling device  100 . 
         [0066]    Additionally, or alternatively, the control subsystem  646  may include one or more user operable input elements, such as switches, keys or buttons, which may include the function buttons  110 . The input elements may include a switch for turning the sampling device  1000 N and OFF. Additionally, or alternatively, the input elements may include one or more switches or keys for controlling operation of a test device that can, for example, download or upload data or instructions to, or from the sampling device  100 . 
         [0067]      FIG. 7  shows a view  700  of the interior parts shown in  FIG. 6 , relative to the cap  102   c  and to the sample chamber  102   b .  FIG. 7  also shows, from above the sampling device  100 , the system geometry, including locations of the emitters  634  and the primary sampling detectors or sensors  638  and  640 . 
         [0068]      FIG. 7  further includes a ray drawing superimposed onto the view  700 , in which arrows indicate transmission paths of electromagnetic energy relative to the interior parts of the sampling device  100 . In one embodiment, emitters  634  are selectively operable to emit electromagnetic energy in a respective range of wavelengths through an emission angle that is substantially centered on an optical axis  702 . The electromagnetic energy is generally blocked by the calibrator PCBA  604  except where the energy is transmitted through a PCBA slit  704  in the calibrator PCBA  604 . The PCBA slit  704  can be substantially aligned with one or more of the emitters  634 . Electromagnetic waves admitted through the PCBA slit  704  continue to propagate toward and through a first aperture  706  of the sample chamber  102   b  and through the transparent walls of the sample cuvette  114 . A second aperture  708  of the sample chamber  102   b  is positioned at least partially across at least a portion of the sample chamber  102   b  from the first aperture  706 . A third aperture  710  of the sample chamber  102   b  is positioned at least partially across at least a portion of the sample chamber  102   b  from both the first and the second apertures  706  and  708 , respectively. The first, second, and third apertures,  706 ,  708 , and  710  are transmissive of electromagnetic energy of at least some wavelengths in an optical portion of the electromagnetic spectrum, as is the sample cuvette  114 . 
         [0069]    As the ray drawing indicates, electromagnetic energy strikes the sample or specimen and is scattered and/or reflected therefrom. The scattered electromagnetic waves then emerge from the at least partially transparent walls of the sample cuvette  114 , propagating outward in various directions. Again, the electromagnetic energy is generally blocked by the walls of the sample chamber  102   b , except where the second aperture  708  permits transmission in the forward scattering direction, along the optical axis  702 . The third aperture  710  permits transmission of the scattered energy in a direction perpendicular to the optical axis  702 , along a perpendicular axis  703 . 
         [0070]    After passing through the second aperture  708 , a portion of scattered electromagnetic energy propagating along the optical axis  702  falls incident on, and thus can be detected by the first primary sampling detector(s) or sensor(s)  638  mounted on the direct sensor PCBA  606 . Similarly, after passing through the third aperture  710 , a portion of scattered electromagnetic energy propagating along the perpendicular axis  703  can be detected at one or more of the second primary sampling detector(s) or sensor(s)  640  mounted on the direct sensor PCBA (also the backplane PCBA)  608 . In some applications, time varying processes, for example, chemical or biological reactions, can be monitored by detecting the onset of, or change(s) in, “side scatter” along the perpendicular axis  703 . Onset of such side scatter can indicate, for example, formation of crystals, bacterial growth, formation of blood clots, or other substances in a fluid that can cause electromagnetic energy to be scattered in the direction of the second primary sampling detector(s) or sensor(s)  640 . Commensurate with an increase in side scatter along the perpendicular axis  703 , there may be observed a decrease in transmission of electromagnetic energy along the optical axis  702 . In some instances, such a decrease in transmission intensity and an increase in side scatter intensity can be observed substantially simultaneously (i.e., concurrently) using the sampling device  100 . The ability to detect such changes represents a feature of the sampling device  100  that is not provided by other types of sampling devices. 
         [0071]      FIG. 8  shows a view  800  of the sample chamber  102   b . The sample chamber  102   b  receives and protects the sample cuvette  114  containing the fluid sample under test. The sample cuvette  114  can be inserted at least partially into the center of the sample chamber  102   b , which fits closely around the sample cuvette  114 . In one embodiment, the sample chamber  102   b  can be raised and lowered during loading of the sample cuvette. The sample chamber  102   b  can serve as a double containment receptacle to prevent liquids that may escape the sample cuvette  114  from coming into contact with electronic components of the sampling device  100 . The sample chamber  102   b  can feature a plurality of apertures described above, e.g., the first aperture  706 , the second aperture  708 , and the third aperture  710 , to allow electromagnetic energy to be transmitted to and scattered (or re-emitted) from a sample within the sample cuvette  114 . In this way, the sample chamber  102   b  guides light into the sample cuvette  114 . Otherwise, the walls of the sample chamber can be opaque, such that the sample chamber  102   b  has at least one opaque wall. The first aperture  706  in the sample chamber  102   b  allows passage of incident electromagnetic energy from one or more of the emitters  634 , along the optical axis  702 , and through the sample cuvette  114  to interact with the fluid sample. In one embodiment, the second aperture  708  is diametrically opposed to the first aperture  706 , allowing passage of scattered electromagnetic energy in the forward direction to exit the sample chamber  102   b  for detection. The third aperture  710  is disposed along a second axis  703 , non-collinear with the optical axis  702 . In the embodiment shown, the second axis  703  and the third aperture  710  are oriented perpendicular to the optical axis  702 . As illustrated, the first aperture  706  is shown larger than the third aperture  710 . However, the relative dimensions of the apertures  706 ,  708 , and  710  can change depending on the type of emitters  634 , the nature of the sample, and other variables. 
         [0072]      FIG. 9  shows a view  900  of the PCBAs  602 ,  604 ,  606 , and  608 , relative to the sample cuvette  114 , in which the calibration sensors  636  and the primary sampling detector(s) or sensor(s)  638 ,  640  are visible. In an exemplary embodiment, the PCBAs  602 ,  604 ,  606 , and  608  can attach to the housing  102  by fitting notches  902  onto clips  904  (see  FIG. 12 ). The clips  904  can, in turn, be secured to an interior surface of the base of the housing  106   a . When mounted in front of the transducer PCBA  602 , the calibrator PCBA  604  serves as a mask in which the PCBA slit  704  allows electromagnetic energy to reach and interact with the fluid sample. The transparent sample cuvette  114  allows electromagnetic energy scattered from the fluid sample to reach the primary sampling detector(s) or sensor(s)  638 . 
         [0073]    As is best illustrated in  FIG. 9 , the transducer PCBA  602  carries a number of emitters or sources  634  arranged, for example, in a linear array on the transducer PCBA  602 . The emitters  634  may be all aligned with the PCBA slit  704  and the first aperture  706 . A full range of emitters can include, for example, 5-10 emitter chips in which each emitter can be made to produce a range of wavelengths of light depending on the electric current supplied to it. Respective ranges of emitters can overlap such that a full range of desired wavelengths can be produced by driving a few emitters at many different current levels. The emitters  634  may take a variety of forms which are operable to emit electromagnetic energy. The emitters  634  may, for example, take the form of one or more light emitting diodes (LEDs), including for instance organic LEDs (OLEDs). Alternatively, or additionally, the emitters  634  may take the form of one or more lasers, for example one or more laser diodes. The lasers may, or may not, be tunable lasers. Alternatively, or additionally, the emitters  634  may take the form of one or more incandescent sources such as conventional or halogen light bulbs. 
         [0074]    One, more, or all of the emitters  634  may be operable to emit in part or all of an “optical” portion of the electromagnetic spectrum, including the (human) visible portion, near infrared (N-IR) portion and/or or near ultraviolet (N-UV) portions of the electromagnetic spectrum. Additionally, or alternatively, the emitters  634  may be operable to emit electromagnetic energy other portions of the electromagnetic spectrum, for example the infrared, ultraviolet and/or microwave portions. 
         [0075]    In some embodiments, at least some of the emitters  634  are operable to emit in or at a different band than other of the emitters  634 . For example, one or more emitters  634  may emit in a band centered around 450 nm, while one or more of the emitters  634  may emit in a band centered around 500 nm, while a further emitter or emitters emit in a band centered around 550 nm. Each of the emitters  634  may emit in a band centered around a respective frequency or wavelength, different than each of the other emitters  634 . Using emitters  634  with different band centers advantageously maximizes the number of distinct samples that may be captured from a fixed number of emitters  634 . This may be particularly advantageous where the sampling device  100  is relatively small, and has limited space or footprint for the emitters  634 . 
         [0076]    The distribution of spectral content for each emitter  634  may vary as a function of drive level (e.g., current, voltage, duty cycle), temperature, and other environmental factors, depending on the specific emitter  634 . Such variation may be advantageously actively employed to operate one or more of the physical emitters  634  as a plurality of “logical emitters or sources,” each of the logical emitters or sources operable to provide a respective emission spectra from a respective physical emitters or source  634 . Thus, for example, the center of the band of emission for each emitters or source  634  may vary according to a drive level and/or temperature. For example, the center of the band of emission for LEDs will vary with drive current or temperature. One way the spectral content can vary is that the peak wavelength can shift. However, the width of the band, the skew of the distribution, the kurtosis, etc., can also vary. Such variations may be also be advantageously employed to operate the physical emitters or sources  634  as a plurality of logical emitters or sources. Thus, even if the peak wavelength were to remain constant, the changes in bandwidth, skew, kurtosis, and any other change in the spectrum can provide useful variations in the operation of the sampling device  100 . Likewise, the center of the band of emission may be varied for tunable lasers. Varying the center of emission bands for one or more emitters  634  advantageously maximizes the number of samples that may be captured from a fixed number of emitters  634 . Again, this may be particularly advantageous where the sampling device  100  is relatively small, and has limited space or footprint for the emitters  634 . 
         [0077]    As is best illustrated in  FIG. 10 , the calibration PCBA  604  carries a number of calibration detectors or sensors (four shown, collectively  636 ), arranged around the PCBA slit  704 . The number of calibration detectors or sensors  636  can correspond to the number of emitters  634 . The calibration detectors or sensors  636  are generally aligned with respective emitters  634 , the calibration detectors or sensors  636  and emitters  634  for example being arranged in linear segments on a surface of the calibration PCBA  604 . The calibration detectors or sensors  636  may match a nominal output of the respective emitter  634  to which the calibration detector or sensor  636  is paired. Thus, some of the calibration detectors or sensors  636  may be responsive to different respective bands of wavelengths than the others. Such bands may be mutually exclusive or may be overlapping. Some embodiments employ one or more wideband calibration detectors or sensors  636 , for example, a pyroelectric detector from Pyreos Ltd. Such may advantageously reduce parts counts, while still allowing calibration across the range of wavelengths of the emitters  634 . Optionally, one or more filters (not shown) may be employed with the calibration detectors or sensors  636 , for example one or more low pass filters, high pass filters, and/or band pass filters. The filters may be optical filters and may be formed or carried directly on the calibration detectors or sensors  636 . Alternatively, the filters may be formed on or carried on another surface, in the field of view of but spaced from the calibration detectors or sensors  636 . 
         [0078]    The calibration detector(s) or sensor(s)  636  can take a variety of forms suitable for sensing or responding to electromagnetic energy. For example, the calibration detector(s) or sensor(s)  636  may take the form of one or more photodiodes (e.g., germanium photodiodes, silicon photodiodes). Alternatively, or additionally, the calibration detector(s) or sensor(s)  636  may take the form of one or more photomultiplier tubes. Alternatively, or additionally, the calibration detector(s) or sensor(s)  636  may take the form of one or more CMOS image sensors. Alternatively, or additionally, the calibration detector(s) or sensor(s)  636  may take the form of one or more charge coupled devices (CCDs). Alternatively, or additionally the calibration detector(s) or sensor(s)  636  may take the form of one or more micro-channel plates. Other forms of electromagnetic sensors may be employed, which are suitable to detect the wavelengths expected to be returned in response to the particular illumination and properties of the object being illuminated. 
         [0079]    The calibration detector(s) or sensor(s)  636  may be formed as individual elements, one-dimensional array of elements and/or two-dimensional array of elements. For example, the calibration detector(s) or sensor(s)  636  may be formed by one germanium photodiode and one silicon photodiode, each having differing spectral sensitivities. A test device may employ a number of photodiodes with identical spectral sensitivities, with different colored filters (e.g., gel filters, dichroic filters, thin-film filters, etc) over the photodiodes to change their spectral sensitivity. This may provide a simple, low-cost approach for creating a set of sensors with different spectral sensitivities, particularly since germanium photodiodes are currently significantly more expensive that silicon photodiodes. Also for example, the calibration detector(s) or sensor(s)  636  may be formed from one CCD array (one-dimensional or two-dimensional) and one or more photodiodes (e.g., germanium photodiodes and/or silicon photodiodes). For example, the calibration detector(s) or sensor(s)  636  may be formed as a one- or two-dimensional array of photodiodes. A two-dimensional array of photodiodes enables very fast capture rate (i.e., camera speed) and may be particularly suited to use in assembly lines or high speed sorting operations. For example, the calibration detector(s) or sensor(s)  636  may be formed as a one- or two-dimensional array of photomultipliers. Combinations of the above elements may also be employed. 
         [0080]    In some embodiments, the calibration detector(s) or sensor(s)  636  may be a broadband sensor sensitive or responsive over a broad band of wavelengths of electromagnetic energy. In some embodiments, the calibration detector(s) or sensor(s)  636  may be narrowband sensors sensitive or responsive over a narrow band of wavelengths of electromagnetic energy. In some embodiments, the calibration detector(s) or sensor(s)  636  may take the form of several sensor elements, as least some of the sensor elements sensitive or responsive to one narrow band of wavelengths, while other sensor elements are sensitive or responsive to a different narrow band of wavelengths. This approach may advantageously increase the number of samples that may be acquired using a fixed number of sources. In such embodiments the narrow bands may, or may not, overlap. 
         [0081]    As is best illustrated in  FIG. 11 , the direct sensor PCBA  606  carries a number of first primary sampling sensors  638   a - 638   d  (four shown, collectively  638 ) positioned opposite the PCBA slit  704 . The first primary sampling sensors  638  may, for example, include two or more sampling sensors or detectors, each responsive to a respective band of wavelengths. Such bands may be mutually exclusive or overlapping. The illustrated embodiment employs four first primary sampling detectors or sensors  638   a - 638   d , each responsive to a respective band of wavelengths (i.e., 400 nm-1100 nm, 400 nm-1050 nm, 400 nm-1050 nm, 600 nm-1700 nm, respectively). Three of the first primary sampling detectors or sensors  638   a - 638   c  that are responsive to N-UV wavelengths are employed to increase to sensitivity. Another embodiment employs one or more wideband first primary sampling detector(s) or sensor(s)  638   d , for example, a pyroelectric detector from Pyreos Ltd. Optionally, one or more filters (not shown) may be employed with the first primary sampling detector(s) or sensor(s)  638 , for example one or more low pass filters, high pass filters, and/or band pass filters. The filters may be optical filters and may be formed or carried directly on the first primary sampling detector(s) or sensor(s). Alternatively, the filters may be formed on or carried on another surface, in the field of view of but spaced from the first primary sampling sampling detector(s) or sensor(s)  638 . 
         [0082]    The first primary sampling detector(s) or sensor(s)  638 , or spectrophotometers, can take a variety of forms suitable for sensing or responding to electromagnetic energy. For example, the primary sampling sensor(s)  638  may take the form of one or more photodiodes (e.g., germanium photodiodes, silicon photodiodes). Alternatively, or additionally, the primary sampling detector(s) or sensor(s)  638  may take the form of one or more photomultiplier tubes. Alternatively, or additionally, the first primary sampling detector(s) or sensor(s)  638  may take the form of one or more CMOS image sensors. Alternatively, or additionally, the first primary sampling detector(s) or sensor(s)  638  may take the form of one or more charge coupled devices (CCDs). Alternatively, or additionally the first primary sampling detector(s) or sensor(s)  638  may take the form of one or more micro-channel plates. Other forms of electromagnetic sensors may be employed, which are suitable to detect the wavelengths expected to be returned in response to the particular illumination and properties of the object being illuminated. 
         [0083]    The first primary sampling detector(s) or sensor(s)  638  may be formed as individual elements, one-dimensional array of elements and/or two-dimensional array of elements. For example, the first primary sampling detector(s) or sensor(s)  638  may be formed by one germanium photodiode and one silicon photodiode, each having differing spectral sensitivities. A test device can be configured with a number of photodiodes having identical spectral sensitivities, with different colored filters (e.g., gel filters, dichroic filters, thin-film filters, etc.) over the photodiodes to change their spectral sensitivity. This may provide a simple, low-cost approach for creating a set of sensors with different spectral sensitivities, particularly since germanium photodiodes are currently significantly more expensive that silicon photodiodes. Also for example, the first primary sampling detector(s) or sensor(s)  638  may be formed from one CCD array (one-dimensional or two-dimensional) and one or more photodiodes (e.g., germanium photodiodes and/or silicon photodiodes). For example, the first primary sampling detector(s) or sensor(s)  638  may be formed as a one- or two-dimensional array of photodiodes. A two-dimensional array of photodiodes enables very fast capture rate (i.e., camera speed) and may be particularly suited to use in assembly lines or high speed sorting operations. For example, the first primary sampling detector(s) or sensor(s)  638  may be formed as a one- or two-dimensional array of photomultipliers. Combinations of the above elements may also be employed. 
         [0084]    In some embodiments, the primary sampling detector(s) or sensor(s)  638 ,  640  may be a broadband sensor sensitive or responsive over a broad band of wavelengths of electromagnetic energy. In some embodiments, the primary sampling detector(s) or sensor(s)  638 ,  640  may be narrowband sensors sensitive or responsive over a narrow band of wavelengths of electromagnetic energy. In some embodiments, the primary sampling detector(s) or sensor(s)  638 ,  640  may take the form of several sensor elements, as least some of the sensor elements sensitive or responsive to one narrow band of wavelengths, while other sensor elements are sensitive or responsive to a different narrow band of wavelengths. This approach may advantageously increase the number of samples that may be acquired using a fixed number of sources. In such embodiments the narrow bands may, or may not, overlap. 
         [0085]    At least one of the PCBAs  602 ,  604 ,  606 , and  608  can also carry one or more thermal sensors (not explicitly shown). The thermal sensors are desirably distributed to detect temperature at a variety of points or locations. Such temperatures may be indicative of temperatures to which the emitters  634 , first primary sampling detectors or sensors  638  and/or calibration detectors or sensors  636  are subjected. Temperature indicative signals from the thermal sensors may be employed in calibration, for example, calibrating results or responses and/or calibrating drive signals to account from variation from nominal temperatures or other conditions. 
         [0086]    Table A, below, provides an exemplary list of suitable parts for the emitters and sensors. Such is purely illustrative and is not intended to require any specific parts, specific wavelengths, or sensitivities. 
         [0000]    
       
         
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE A 
               
               
                   
               
               
                 Ref. No. 
                 Part No. 
                 Description 
                 Default/Qty. 
               
               
                   
               
             
             
               
                 606 
                 Max2 Sensor PCBA 
                 PCBA 
                 1 
               
               
                 — 
                 MCP98242 
                 Thermal Sensor 
                 4 
               
               
                 644a 
                 HSEC8-120-01-X-DV 
                 Connector 
                 1 
               
             
          
           
               
                 634a 
                 350-PLCC2-120 
                 352 
                 nm 
                 1 
               
               
                 634b 
                 SM1206UV-395-IL 
                 400 
                 nm 
                 1 
               
               
                 634c 
                 EL-19-21/BHC-AN1P2/3T 
                 468 
                 nm 
                 1 
               
               
                 634d 
                 PG1112C-TR 
                 567 
                 nm 
                 1 
               
               
                 634e 
                 LTST-C190KYKT 
                 595 
                 nm 
                 1 
               
               
                 634f 
                 SMC810 
                 810 
                 nm 
                 1 
               
               
                 634g 
                 SMC1200 
                 1200 
                 nm 
                 1 
               
               
                 634h 
                 LNJ812R83RA 
                 630 
                 nm 
                 1 
               
               
                 634i 
                 SMC1450 
                 1450 
                 nm 
                 1 
               
               
                 634j 
                 SMC910 
                 910 
                 nm 
                 1 
               
               
                 634k 
                 LN1251CTR 
                 700 
                 nm 
                 1 
               
               
                 634l 
                 SMC970 
                 970 
                 nm 
                 1 
               
               
                 636a 
                 PDB-C152SM 
                 400-1100 
                 nm 
                 1 
               
               
                 636b 
                 SFH2701 
                 400-1050 
                 nm 
                 1 
               
               
                 636c 
                 PDB-C152SM 
                 400-1100 
                 nm 
                 1 
               
               
                 636d 
                 LAPD-1-06-17-LCC 
                 600-1700 
                 nm 
                 1 
               
               
                 638a 
                 SFH2701 
                 400-1050 
                 nm 
                 1 
               
               
                 638b 
                 SFH2701 
                 400-1050 
                 nm 
                 1 
               
               
                 638c 
                 PDB-C152SM 
                 400-1100 
                 nm 
                 1 
               
               
                 638d 
                 PDB-C152SM 
                 400-1100 
                 nm 
                 1 
               
               
                 638e 
                 PDB-C152SM 
                 400-1100 
                 nm 
                 1 
               
               
                 638f 
                 PDB-C152SM 
                 400-1100 
                 nm 
                 1 
               
               
                 638g 
                 LAPD-1-06-17-LCC 
                 600-1700 
                 nm 
                 1 
               
               
                 638h 
                 PDB-C152SM 
                 400-1100 
                 nm 
                 1 
               
               
                 638i 
                 LAPD-1-06-17-LCC 
                 600-1700 
                 nm 
                 1 
               
               
                 638j 
                 PDB-C152SM 
                 400-1100 
                 nm 
                 1 
               
               
                 638k 
                 PDB-C152SM 
                 400-1100 
                 nm 
                 1 
               
               
                 638l 
                 PDB-C152SM 
                 400-1100 
                 nm 
                 1 
               
               
                   
               
             
          
         
       
     
         [0087]    By commonly housing emitters  634  with respective calibration detector(s) or sensor(s)  636  or sensors  638 , the sampling device may automatically take or capture an electromagnetic energy calibration sample or measurement each time an emitter emits electromagnetic energy. Such is performed in real-time, without any separate calibration mode. Such may be performed individually for each emitter, one at a time, as the emitter is activated. Thermal sensors  635  may be sampled each time an emitter is activated. Alternatively, the thermal sensors  635  may be sampled periodically or aperiodically. The electromagnetic energy calibration sample or measurements and thermal calibration sample or measurements may be used to calibrate a detected or measured response. The electromagnetic energy calibration sample or measurements and thermal calibration sample or measurements may additionally or alternatively be used to control operation, for instance to control a drive signal supplied to the emitters, or control an amplification applied to a signal produced or provided by the first primary sampling detectors or sensors  638 . As discussed below, the electromagnetic energy calibration sample or measurements and thermal calibration sample or measurements may be processed on the sampling device  100 , or sent to a separate component (e.g., digital computer) for processing. 
         [0088]    While  FIGS. 9-11  show seven emitters  634 , four calibration detector(s) or sensor(s)  636  and eight primary sampling detectors or sensors  638 ,  640 , other embodiments may include fewer or greater number of emitters  634 , and calibration detector(s) or sensor(s)  636  or primary sampling detector(s) or sensor(s)  638 ,  640 . The total number of emitters  634 , calibration detector(s) or sensor(s)  636 , and primary sampling detector(s) or sensor(s)  638 ,  640 , should not be considered limiting. 
         [0089]      FIG. 12  shows a view  1200  of the sampling device  100  as seen from the rear. Internal parts are shown relative to overall structural components such as the main body housing portion  102   a , the cap  102   c , the hinged lid  117 , and the sample chamber  102   b . Superimposed onto the structure of the sampling device  100  is a side view of a ray diagram similar to that shown in  FIG. 7 . In the view  1200 , electromagnetic energy is shown being emitted through a wide range of angles from the exemplary top and bottom emitters  634   a  and  634   g . The diameter of the emitted beam may depend on the nature of the emitter. The outermost rays  1202   a  and  1202   g , emanating from the emitters  634   a  and  634   g , respectively, fail to pass through the PCBA slit  704  (not shown) and therefore do not interact with the sample. If the emitters  634  are laser sources, for example, the outermost rays may not be relevant because laser sources produce a collimated beam. (However, even a collimated beam may exhibit spreading.) In general, a portion of the energy emitted can be expected to escape the system without encountering the sample under test. The innermost rays emitted,  1204   a  and  1204   g , respectively, are shown crossing at the center of the sample cuvette  114 , in front of the second primary sampling detector(s) or sensor(s)  640 , which are attached to the backplane  608 . The innermost rays therefore interact with substantially the same part of the sample contained in the sample cuvette  114 . It is noted that the innermost rays shown have different wavelengths because they originate at different sources. A portion of the electromagnetic energy in the innermost rays  1204   a  and  1204   g  is scattered by the sample. Some of the scattered energy is shown continuing to propagate in the forward direction for detection by the sensors  638 . Thus, comparing the energy scattered by the same sample at multiple wavelengths permits identification of a localized portion of the sample. Meanwhile, the central rays  1206   a  and  1206   g , from the two different emitters  634   a  and  634   g , respectively, interact with different portions of the fluid sample. The central rays are also scattered, and a portion of this scattered energy propagates to the detectors  638 . By comparing the scattered energy from the central rays  1206   a  and  1206   g  with that from the innermost rays  1204   a  and  1204   g , information about the homogeneity of the sample can be obtained. For example, particles suspended in the fluid can be identified and distinguished from the fluid itself. 
         [0090]      FIG. 13  shows a sampling system  1300 , according to one illustrated embodiment. The sampling system  1300  includes one or more sampling devices  100  (one shown). The sampling system  1300  includes one or more processor-based devices  1302  (one shown). While illustrated as a mobile or handheld processor-based device  1302 , for instance a Smartphone type device, the processor-based device  1302  may take a large variety of other forms. For example, the mobile or handheld processor-based device  1302  may take the form of the various computers or computing systems, such as a desktop or laptop personal computer, tablet computer, netbook computer, mini-computer, mainframe computer, or server computer. 
         [0091]    The sampling device  100  is communicatively coupled to the processor-based device  1302 . 
         [0092]    The sampling device  100  may be communicatively coupled to the processor-based device  1302  via a physical communicative path such as a cable  1304 . 
         [0093]    The cable  1304  will typically include a connector proximate at least one end thereof, and often at both ends. For example, the cable  1304  may have a first connector  1304   a  (e.g., plug) at a first end  1306   a , the first connector  1304   a  selectively detachably coupleable to a complimentary connector or port  1308  on the processor-based device  1302 . Also for example, the cable  1304  may have a second connector  1304   b  (e.g., plug) at a second end  1306   b , the second connector  1304   b  selectively detachably coupleable to a complimentary connector or port on the sampling device  100  such as the cable receptacle  504 . Alternatively, the second end of the cable  1304  may be permanently fixed to the sampling device  100 . The physical ports and/or connectors  1304   a ,  1304   b ,  1308 ,  504  and/or cables  1304  may comply with any variety of physical and/or logical standards, and may incorporate one or more integrated circuits. For instance, the ports and/or connectors  1304   a ,  1304   b ,  1308 ,  504  and/or cables  1304  may comply with standards required of USB® standards or Apple Computer&#39;s Lighting® standards. 
         [0094]    The cable  1304  may, for instance, include a number of distinct electrical conductors (e.g., wires) (not shown) to provide signals between the sampling device  100  from the processor-based device  1302 . The electrical conductors may provide for bi-directional communications between the sampling device  100  and the processor-based device  1302 . The cable  1304  may additionally provide electrical power (e.g., 5V, 10V) to the sampling device  100  from the processor-based device  1302 . In such an implementation, the sampling device  100  may omit any on-board consumable power source (e.g., primary or secondary chemical battery, ultra-capacitor, fuel cell) (not shown). Alternatively, the sampling device  100  may include a recharging circuit (not shown) that uses electrical power supplied via the cable  1304  to recharge an onboard power source (e.g., secondary chemical battery, ultra-capacitor, fuel cell) (not shown). 
         [0095]    The cable  1304  may include one or more optical paths (e.g., optical fibers) (not shown). The optical paths may provide for bi-directional communications between the sampling device  100  and the processor-based device  1302 . 
         [0096]    The sampling device  100  may be communicatively coupled to the processor-based device  1302  via a wireless (e.g., radio frequency, microwave, visible or IR light) communicative path. As discussed below, many processor-based devices  1302  include various radios or receivers, including ones that are compliant with cellular (e.g., CDMA, GSM, LTE), BLUETOOTH or WI-FI protocols. In such implementations, the sampling device  100  may include one or more radios or transceivers (not shown) can be implemented as one or more integrated circuits and/or antennas (not shown). The integrated circuits and/or antennas (not shown) may be carried by the backplane PCBA  608  or some other PCBA, for instance a dedicated communications PCBA (not shown). In such implementations, the sampling device  100  will typically require an on-board consumable power source (e.g., primary or secondary chemical battery, ultra-capacitor, fuel cell) (not shown). 
         [0097]    The sampling device  100  may be communicatively coupled via one or more networks (not shown) to various processor-based devices  1302  and/or other sampling devices  100 . The network(s) may take a variety of forms including LANs, WANs, WLANs, WWANs, PSTN, to name a few. Such may, for example allow access to one or more storage or databases of information. Such may, for example allow updating or reconfiguration, for instance by downloading of processor-executable instructions. Such may, for example, allow troubleshooting of the sampling device  100  should an error condition occur. 
         [0098]    The processor-based device  1302  may include a user interface which may, for example include a touch-sensitive display  1312 , speakers  1314  (one shown), microphones  1316   a ,  1316   b  (collectively  1316 ), and/or an audio output port  1318 . The user interface may also include user selectable icons, collectively  1320 , and/or one or more physical switches, keys or buttons  1322 . 
         [0099]      FIG. 13  further illustrates a PCBA  1324  of the processor-based device  1302 , removed therefrom to better illustrate various components housed within a housing of the processor-based device  1302 . The processor-based device  1302  includes one or more processors, for instance a microprocessor  1326 . The processor-based device  1302  includes one or more non-transitory computer- or processor-readable media, for instance ROM or Flash  1328  and/or RAM  1330 . 
         [0100]    Referring to  FIG. 13 , the microprocessor  1326  employs instructions and or data from the ROM/Flash  1328  and/or RAM  1330  in controlling operation of the sampling device  100 . For example, the processor  1326  operates the emitters  634  in one or more sequences. The sequences determine an order in which the emitters  634  are turned ON and OFF. The sequences may also indicate an ordered pattern of drive levels (e.g., current levels, voltage levels, duty cycles) for the emitters  634 . Thus, for example, the processor  1326  may cause the application of different drive levels to respective ones of the emitters  634  to cause the emitters  634  to emit in distinct bands of the electromagnetic spectrum. The processor  1326  may process information generated by the first primary sampling detector(s) or sensor(s)  638 , which is indicative of the response by at least a portion of a sample or specimen to illumination by the emitters  634 . The information at any given time may be indicative of the response by the sample or specimen to illumination by one or more of the emitters  634 . Thus, the information over a period of time may be indicative of the responses by the sample or specimen to sequential illumination by each of a plurality of the emitters  634 , where each of the emission spectra of each of the emitters  634  has a different center, bandwidth and/or other more complex differences in spectral content, such as those described above (e.g., width of the band, the skew of the distribution, the kurtosis, etc.). 
         [0101]    The processor  1326  employs instructions and or data from the ROM/Flash  1328  and RAM  1330  to perform analysis or evaluation of the responses. For example, the processor  1326  may compare a response to one or more reference responses. The processor  1326  may determine whether a response from a sample or specimen sufficiently matches is signature responses from a reference sample or specimen. Such may, for example, be employed to detect a presence or absence of a substance, for instance an illegal substance (e.g., cocaine), an explosive substance (e.g., nitrate based), or a toxic substance (e.g., carcinogens). The processor  1326  may cause display of a result of an analysis or evaluation. For instance, the processor  1326  may cause display of a simple indicator (e.g., check, YES/NO, other text, GREEN/RED/AMBER or other color) indicative of the result. Also for instance, the processor  1326  may cause display of a more complex indicator (e.g., graph, table chart) indicative of the result. Additionally or alternatively, the processor  1326  may cause an aural indication indicative of a result via speaker  1314 , for example a sound such as a beep, buzz, or even spoken or synthesized words. 
         [0102]    The processor-based device  1302  may additionally include a display driver  1332 , communicatively coupled to drive the touch-sensitive display  1312  and/or detect touches, swipes or other user inputs via the touch-sensitive display  1312 . The display driver  1332  may be a dedicated integrated circuit, for example a graphical processing unit. 
         [0103]    The processor-based device  1302  may additionally include one or more radios or transceivers  1334  (only one shown) and one or more associated antennas  1336  (only one shown). The radios or transceivers  1334  and antennas  1336  may take any of a large variety of forms, for example ones suitable for wireless communications such as cellular communications (e.g., CDMA, GSM, LTE), BLUETOOTH communications and/or WI-FI communications. 
         [0104]    The processor-based device  1302  may additionally include one or more accelerometers or gyroscopes. Such components may be capable of producing data indicative of an orientation of the processor-based device  1302 . Such components may be capable of producing data indicative of a speed, movement or acceleration of the processor-based device  1302 . 
         [0105]    The various components may be communicatively coupled via one or more buses  1338  (only one shown) or other connections, for example data buses, instruction buses, address buses, power buses, etc. 
         [0106]    As used herein and in the claims, longitudinal refers to the major dimension or length of a structure, and is not limited to being an axis of revolution of a profile or cross-section of such structure. 
         [0107]    As used herein and in the claims, the term “non-transitory computer-readable medium” and “non-transitory processor-readable medium” are used interchangeably to refer to any tangible medium that participates in providing instructions for execution or storage of data, parameters or other information. Such a medium may take many forms, including but not limited to, non-volatile media and volatile media. Non-volatile media includes, for example, hard, optical or magnetic disks. Volatile media includes dynamic memory, such as system memory. Common forms of computer- or processor-readable media include, for example, floppy disk, flexible disk, hard disk, magnetic tape, or any other magnetic medium, CD-ROM, any other optical medium, punch cards, paper tape, any other physical medium with patterns of holes, RAM, PROM, EPROM, EEPROM, FLASH memory, any other memory chip or cartridge, or any other tangible medium from which a computer or processor can read. 
         [0108]    While not illustrated, the sampling device  100  may include one or more elements operable to deflect or otherwise position the emitted or received electromagnetic energy. The elements may, for example, include one or more optical elements, for example lens assemblies, mirrors, prisms, diffraction gratings, etc. For example, the optical elements may include an oscillating mirror, rotating polygonal mirror or prism, or MEMS micro-mirror that oscillates about one or more axes. The elements may, for example, include one or more other elements, for example permanent magnets or electromagnets such as those associated with cathode ray tubes and/or mass spectrometers. 
         [0109]    The various embodiments described above can be combined to provide further embodiments. All of the U.S. patents, U.S. patent application publications, U.S. patent applications, foreign patents, foreign patent applications and non-patent publications referred to in this specification and/or listed in the Application Data Sheet, including but not limited to: U.S. Pat. Nos. 7,996,173; 8,081,304; and 8,076,630; U.S. Provisional Patent Application Serial Nos.: 61/760,527, filed Feb. 4, 2013; 60/623,881, filed Nov. 1, 2004; 60/732,163, filed Oct. 31, 2005; 60/820,938, filed Jul. 31, 2006; 60/834,662, filed Jul. 31, 2006; 60/834,589, filed Jul. 31, 2006; 60/871,639, filed Dec. 22, 2006; 60/883,312, filed Jan. 3, 2007; 60/890,446, filed Feb. 16, 2007; 61/538,617, filed Sep. 23, 2011; 61/760,527, filed Feb. 4, 2013; 61/597,586, filed Feb. 10, 2012; 61/597,593, filed Feb. 10, 2012; and 61/767,716, filed Feb. 21, 2013, are incorporated herein by reference, in their entirety. Aspects of the embodiments can be modified, if necessary, to employ systems, circuits and concepts of the various patents, applications and publications to provide yet further embodiments. 
         [0110]    These and other changes can be made to the embodiments in light of the above-detailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the disclosure.