Sensor array continuous capacitance type liquid level sensor

Abstract

Systems, devices, and methods are disclosed for a fluid level sensor that includes a continuous sensor wire located within a tube, where the continuous sensor wire extends from an upper end of the tube to a lower end of the tube. A ground lead is located within the tube, wherein the ground lead extends from the upper end of the tube to the lower end of the tube. A wet reference wire is located within the tube, wherein the wet reference wire extends from the upper end of the tube to the lower end of the tube. A dry reference wire is located within the tube, wherein the dry reference wire is positioned adjacent the upper end of the tube.

Description

Technical Field

[0001] The present disclosure generally relates to systems, devices, and methods for fluid level sensing strips. Specifically, embodiments of the present disclosure relate to systems, devices, and methods for adjustable fluid level sensing strips. Background Art

[0002] Capacitance-based sensing is a common technology modality used to detect liquids in cans, tubes, bottles, and other containers. These sensors come in both continuous and single-point types and are often assembled into tubular geometries, strips, and probes.

[0003] Regardless of the type, these sensors require that the sensing and grounding electrodes (also referred to herein as conductors) be insulated from direct contact with the measured medium. When the insulated electrodes are placed in the presence of the medium, a corresponding change in capacitance occurs. This change is interpreted as a change in liquid level and / or the presence of liquid. However, these prior art sensors require compensation and calibration, which is inconvenient and time consuming. Summary of the invention

[0004] Embodiments of the present invention provide an improved capacitive sensor including a sensor array having a plurality of conductors that provide numerous benefits over the prior art.

[0005] As will be described in more detail below, in some specific implementations discussed herein, systems, devices, and methods implement a fluid level sensor that includes a continuous sensor wire located within a tube, wherein the continuous sensor wire extends from an upper end of the tube to a lower end of the tube. A ground wire is located within the tube, wherein the ground wire extends from the upper end of the tube to the lower end of the tube. A wet reference wire is located within the tube, wherein the wet reference wire extends from the upper end of the tube to the lower end of the tube. A dry reference wire is located within the tube, wherein the dry reference wire is positioned adjacent to the upper end of the tube.

[0006] In one example, a fluid level sensor includes a substrate and a continuous sensor plate located on the substrate, wherein the continuous sensor plate extends from an upper end of the substrate to a lower end of the substrate. A continuous ground plate is located on the substrate, wherein the continuous ground plate extends from the upper end of the substrate to the lower end of the substrate. A wet reference capacitive plate is located on the substrate, wherein the wet reference capacitive plate is located adjacent to the lower end of the substrate. A dry reference capacitive plate is located on the substrate, wherein the dry reference capacitive plate is located adjacent to the upper end of the substrate.

[0007] In another example, operation of a fluid level sensor includes sensing a fluid capacitance level via a continuous sensor wire located within a tube, wherein the continuous sensor wire extends from an upper end of the tube to a lower end of the tube. Determining a wet reference capacitance value via a wet reference wire located within the tube, wherein the wet reference wire extends from the upper end of the tube to the lower end of the tube. Determining a dry reference capacitance value via a dry reference wire located within the tube, wherein the dry reference wire is positioned adjacent to the upper end of the tube. Determining an output fluid level based on the sensed fluid capacitance level, the wet reference capacitance value, and the dry reference capacitance value.

[0008] In another example, operation of a fluid level sensor includes: sensing a fluid level via a continuous sensor plate of the fluid level sensor, wherein the sensor plate extends from an upper end of a substrate to a lower end of the substrate. Determining a wet reference value via a wet reference capacitive plate positioned adjacent to the lower end of the substrate. Determining a dry reference value via a dry reference capacitive plate positioned adjacent to the upper end of the substrate. Determining an output fluid level based on the sensed fluid level, the wet reference value, and the dry reference value. Shielding a trace from capacitive interference via a wet reference shield, wherein the trace and the wet reference shield extend from the upper end of the substrate to the wet reference capacitive plate.

[0009] The present invention summary is provided to introduce a series of concepts in a simplified form, which are further described in the detailed description below. When read in conjunction with the accompanying drawings, the above invention summary and the detailed description of certain specific implementations below will be better understood. The present invention summary is not intended to identify the key features or essential features of the claimed subject matter, nor is it intended to be used to help determine the scope of the claimed subject matter. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The foregoing and other features and advantages will be discussed in detail in the following non-limiting description of specific embodiments in conjunction with the accompanying drawings, in which:

[0011] Figure 1 illustrates a front view of a fluid level sensor according to an example of the present disclosure;

[0012] Figure 2 illustrates a front view of another fluid level sensor according to an example of the present disclosure;

[0013] Figure 3 The example according to the present disclosure is illustrated Figure 2 A cross-sectional side view of a fluid level sensor;

[0014] Figure 4 A schematic diagram illustrating a data processor according to an example of the present disclosure;

[0015] Figure 5is an illustration of a flow chart of an exemplary method for fluid level sensing according to examples of the present disclosure;

[0016] Figure 6 is a diagram illustrating a simulation of the operation of an embodiment of the present invention according to an example of the present disclosure;

[0017] Figure 7 is a block diagram illustrating a computer program product according to an example of the present disclosure;

[0018] Figure 8 is a block diagram illustrating an exemplary fluid delivery device according to examples of the present disclosure; and

[0019] Fig. 9 is a block diagram illustrating a hardware device including a semiconductor package according to an example of the present disclosure. DETAILED DESCRIPTION

[0020] Some embodiments of the present invention include a sensor housing (e.g., a tube). The sensor housing can be a tube made of metal, plastic, or any other suitable material that is sealed to prevent media from entering and contains suitable mountings to the vessel entry point. Within the tube is a sensor array that is responsible for sensing the changing liquid medium level when the sensor array surrounds the tubular housing. The sensor array may include a wire harness, a circuit board, a combination of the two, or any other suitable configuration.

[0021] In some embodiments, the sensor array includes a sensing conductor (referred to herein as CL or C-LEVEL). CL is an unshielded conductor (twisted or single strand) that runs the entire length of the sensor and is responsible for reporting the continuous change in capacitance as the media level changes.

[0022] In some embodiments, the sensor array includes an environmental reference conductor (referred to herein as RE). The RE is a shielded conductor that extends only a small portion of the top of the sensor array (where the shield is removed, exposing the conductor) and is responsible for compensating for changes in the sensor environment (e.g., ambient air temperature, etc.).

[0023] In some embodiments, the sensor array includes a liquid reference conductor (referred to herein as RL). The RL is a shielded conductor that extends the sensor length equal to CL, with the shield removed only at the end of the extension, exposing the conductor. The RL is responsible for changes in the dielectric of the medium. In this way, for example, two identical sensors immersed in two different media types will show the same output for a common liquid level because the difference in the dielectric constant (or relative permittivity) is accounted for by the value measured by the RL. Or, as another example, a sensor in a medium will not report significant level changes due to temperature changes in the medium.

[0024] In some embodiments, the sensor array includes a ground conductor (referred to herein as GND). In a plastic tube, the GND is an unshielded conductor that extends a sensor length equal to CL and acts as a ground. In a metal tube, the GND may be bonded to the housing, and the housing acts as a ground.

[0025] In some embodiments, some or all of the previously described sensors (including associated shields) may be printed onto a suitable ridged substrate. The responsibilities of each sensor remain the same as in the previously described embodiments, and the printed construction may provide a more stable and convenient construction by utilizing a multi-layer printed circuit board (PCB).

[0026] In some embodiments, some or all of the previously described sensors (including associated shields) may be printed onto a suitable flexible substrate. The responsibilities of each sensor remain the same as in the previously described embodiments. The printed flexible construction enables complete non-contact sensing by applying a suitable adhesive necessary to connect the flexible embodiment to the outside of the container of interest. In this embodiment, an additional shielding layer is utilized on top of the non-sensing side of the flexible construction to be unaffected by erroneous signals originating from the outside of the container of interest.

[0027] Figure 1 A fluid level sensor 100 embodiment of the present invention using a wiring harness is depicted, wherein from left to right a dry reference wire 110 (RE), a continuous sensor wire 104 (CL), a ground wire (GND), and a wet reference wire 108 (RL) are shown. The fluid level sensor 100 includes a plurality of conductors 121, shields 118, 120, and a plurality of wire sleeves 122 for isolating the conductors 121 (e.g., so that they do not short circuit).

[0028] In some implementations, the fluid level sensor 100 includes a continuous sensor wire 104 positioned within the tube 102, wherein the continuous sensor wire 104 extends from an upper end 103 of the tube 102 to a lower end 105 of the tube. A ground wire 106 is positioned within the tube 102, wherein the ground wire 106 extends from the upper end 103 of the tube to the lower end 105 of the tube. A wet reference wire 108 is positioned within the tube 102, wherein the wet reference wire 108 extends from the upper end 103 of the tube 102 to the lower end 105 of the tube 102. A dry reference wire 110 is positioned within the tube 102, wherein the dry reference wire 110 is positioned adjacent to the upper end 103 of the tube 102. When the sensor 100 is deployed relative to a container, an exposed end 132 of the wet reference wire 108 proximate the lower end 105 of the tube 102 is configured to be at a minimum level of the liquid to be measured, i.e., such that the wet reference wire 108 is able to sense the dielectric constant of any amount of liquid in the container. On the other hand, when the sensor 100 is deployed, the exposed end 142 of the dry reference wire 110 is configured to be above the maximum level of the liquid to be measured, ie, so that the dry reference wire 110 can sense any environmental changes regardless of the level of the liquid in the container.

[0029] In some examples, the fluid level sensor 100 further includes a wet reference shielding sheath 118 that is located over the first covered portion 130 of the wet reference wire 108 so that a second exposed portion 132 of the wet reference wire 108 is not covered by the wet reference shielding sheath 118. Where present, the wet reference shielding sheath 118, which may include a suitable conductive material, shields the wet reference wire 108 from external disturbances, such as any changes in its capacitance due to the measured presence of liquid or other external factors that may affect the measured capacitance. In such an example, the second exposed portion 132 of the wet reference wire 108 is adjacent to the lower end 105 of the tube 102, such that only the presence of liquid proximate to the second exposed portion 132 has any effect on the capacitance of the wet reference wire 108. In some implementations, the wet reference shielding sheath 118 is electrically driven. For example, the wet reference shielding sheath 118 may be driven by the same electrical signal used to measure the capacitance of the continuous sensor wire 104.

[0030] In some implementations, the fluid level sensor 100 further includes a dry reference shield sheath 120, which is substantially similar to the wet reference shield sheath 118, positioned over the first covered portion 140 of the dry reference wire 110 so that a second exposed portion 142 of the dry reference wire 110 is not covered by the dry reference shield sheath 120. In some examples, the dry reference shield sheath 120 is electrically driven in the same manner as the wet reference shield sheath 118.

[0031] In some examples, the continuous sensor wire 104, the ground wire 106, the wet reference wire 108, and the dry reference wire 110 are all flexible. In some implementations, the fluid level sensor 100 is bent to conform to the contours of the container being measured and / or the contours of the tube 102. In some examples, the continuous sensor wire 104, the ground wire 106, the wet reference wire 108, and the dry reference wire 110 are composed of copper, another flexible conductive substance, and / or combinations thereof.

[0032] In operation, the fluid level sensor 100 senses the fluid capacitance level via the capacitance of the continuous sensor wire 104. The wet reference capacitance value is determined via the wet reference wire 108, and the dry reference capacitance value is determined via the dry reference wire 110. The output fluid level is determined based on the sensed fluid capacitance level, the wet reference capacitance value, and the dry reference capacitance value. For example, the output fluid level can be determined by the following formula: Level = (CO-CL) / (RL-RE), where CO is the fluid capacitance level sensed when no fluid is present, CL is the sensed fluid capacitance level, RL is the wet reference capacitance value, and RE is the dry reference capacitance value.

[0033] During operation, shielding can be performed via the wet reference shielding sheath 118. In such an example, the wet reference shielding sheath 118 is electrically driven. Additionally or alternatively, during operation, shielding can be performed via the dry reference shielding sheath 120. In such an example, the dry reference shielding sheath 120 is electrically driven. Such shielding via the wet reference shielding sheath 118 and / or the dry reference shielding sheath 120 prevents interference between components of the fluid level sensor 100 and / or interference by a user (e.g., a user's hand).

[0034] Figure 2 Another fluid level sensor 200 embodiment of the present invention when applied to a ridged or flexible substrate is depicted, wherein from left to right there are shown a continuous ground plate 206 (GND), a dry reference capacitor plate 210 (RE), a continuous sensor plate 204 (CL), a shield 218, and a wet reference capacitor plate 208 (RL) (e.g., wherein Figure 2, the continuous ground plate 206 (GND) is hooked on top of the dry reference capacitor plate 210 (RE) and the continuous sensor plate 204 (CL). For example, the continuous ground plate 206 (GND) is positioned relative to one sensor plate (e.g., the dry reference capacitor plate 210 (RE)) so that the continuous ground plate 206 (GND) does not impose significant stray capacitance on another sensor plate (e.g., the continuous sensor plate 204 (CL)). To achieve this, the continuous ground plate 206 (GND) that is not associated with a given sensor plate (e.g., the continuous sensor plate 204 (CL)) is positioned in an arrangement that is spaced apart from the given sensor plate so as to limit the impact on the given sensor plate (e.g., the farther the continuous ground plate 206 (GND) and the continuous sensor plate 204 (CL) are positioned from each other, the smaller the impact). In the illustrated example, the continuous ground plate 206 (GND) is hooked on the top of the dry reference capacitor plate 210 (RE), on the opposite side of the dry reference capacitor plate 210 (RE) away from the continuous sensor plate 204 (CL) to achieve a spaced arrangement distance between the continuous ground plate 206 (GND) and the continuous sensor plate 204 (CL).

[0035] As used herein, "plate" refers to an electrically conductive material.

[0036] In some implementations, the fluid level sensor 200 includes a continuous sensor plate 204 disposed on a substrate 202, wherein the continuous sensor plate 204 extends from an upper end 203 of the substrate 202 to a lower end 205 of the substrate 202. A continuous ground plate 206 is disposed on the substrate 202, wherein the continuous ground plate 206 extends from an upper end 203 of the substrate 202 to a lower end 205 of the substrate 202. A wet reference capacitor plate 208 is disposed on the substrate 202, wherein the wet reference capacitor plate 208 is positioned adjacent to the lower end 205 of the substrate 202. A dry reference capacitor plate 210 is disposed on the substrate 202, wherein the dry reference capacitor plate 210 is positioned adjacent to the upper end 203 of the substrate 202.

[0037] As discussed above, in some examples, the substrate is flexible. For example, such flexible substrates are composed of polyimide, polyamide, polyester, fluoropolymer, liquid crystal polymer, etc. and / or combinations thereof. In other examples, the substrate is rigid. For example, such rigid substrates are composed of fiberglass, reinforced epoxy resin, etc. and / or combinations thereof.

[0038] In some implementations, the fluid level sensor 200 includes a trace 216 extending from the upper end 203 of the substrate 202 to the wet reference capacitive plate 208 to electrically connect the wet reference capacitive plate 208 to the measurement circuit. In such implementations, the fluid level sensor 200 may also include a wet reference shield 218 positioned adjacent to the trace 216, wherein the wet reference shield 218 extends from the upper end 203 of the substrate 202 to the wet reference capacitive plate 208. In some examples, the wet reference shield 218 is electrically driven.

[0039] In some examples, a tube (e.g., Figure 1 ) is located around the fluid level sensor 200.

[0040] In operation, the fluid level sensor 200 senses the fluid capacitance level via the capacitance of the continuous sensor plate 204. The wet reference capacitance value is determined via the wet reference capacitance plate 208, and the dry reference capacitance value is determined via the dry reference capacitance plate 210. The output fluid level is determined based on the sensed fluid capacitance level, the wet reference capacitance value, and the dry reference capacitance value. For example, the output fluid level can be determined by the following formula: Level = (CO-CL) / (RL-RE), where CO is the fluid capacitance level sensed when the fluid is not present, CL is the sensed fluid capacitance level, RL is the wet reference capacitance value, and RE is the dry reference capacitance value. In addition, shielding the trace 216 from capacitive interference can be performed via a wet reference shield 218. In this example, the wet reference shield can be electrically driven.

[0041] In operation, the fluid level sensor 200 can be adhered to the outside of a container for fluid measurement. In such an example, the fluid level sensor 200 can be bent to conform to the contours of the outside of the container being measured and / or the contours of the tube containing the fluid level sensor 200.

[0042] Figure 3 A cross-sectional view of a fluid level sensor 200 embodiment of the present invention is depicted as applied to a ridged or flexible substrate 202. As illustrated, the fluid level sensor 200 is implemented as a multi-layer PCB including an additional outer shielding layer 302 positioned around a capacitance-to-digital converter 304.

[0043] In some implementations, the fluid level sensor 200 includes an outer shielding layer 302 located on an outer surface 303 of the substrate 202, which is opposite to an inner surface 305 of the substrate 202 where the continuous sensor plate 204 is located. In some examples, the outer shielding layer 302 is formed of copper, another flexible conductive substance, and / or a combination thereof.

[0044] In some examples, the fluid level sensor 200 includes a capacitance-to-digital converter 304, as known in the art, for converting the measured capacitance into a digitally represented value that can be processed by a suitable processing device. In this example, the capacitance-to-digital converter 304 is located on the outer surface 303 of the substrate 202 and in a gap formed in the outer shielding layer 302. Note that for ease of illustration, the electrical connections between the various conductors of the sensors 100, 200 and the capacitance-to-digital converter 304 or the electrical connections between the capacitance-to-digital converter 304 and the data processor are not shown. The techniques for establishing such connections are well known to those skilled in the art.

[0045] In operation, the continuous sensor plate, the wet reference capacitive plate, and the dry reference capacitive plate are shielded from capacitive interference via the outer shielding layer 302. Such shielding via the outer shielding layer 302 prevents interference from a user (eg, a user's hand).

[0046] Figure 4 A schematic diagram of a data processor 400 according to an example of the present disclosure is illustrated. As illustrated, the data processor 400 includes a capacitance-to-digital converter 304 coupled to an input / output (I / O) module 402 via an interconnect 404. Data from the I / O module 402 may be processed by computer-readable instructions 408 associated with a processor 406. In some examples, the computer-readable instructions 408 may be implemented via hardware, firmware, software, and / or a combination thereof.

[0047] In operation, data processor 400 receives capacitance levels from the continuous sensor wire, wet reference wire, and dry reference wire. These capacitance levels are converted to digital values ​​by capacitance-to-digital converter 304 for use by I / O module 402. These digital values ​​are ultimately processed by processor 406 according to computer readable instructions 408.

[0048] Figure 5 is a flow chart of an example of a method 500 for fluid level sensing according to an example. The method 500 may generally be performed by a device (such as, for example, the fluid level sensor 100 ( Figure 1 )) to implement.

[0049] In an example, the method 500 may be implemented in computer-readable instructions (eg, software), configurable computer-readable instructions (eg, firmware), fixed-function computer-readable instructions (eg, hardware), etc., or any combination thereof.

[0050] It should be understood that some or all of the operations of method 500 described using a "pull" architecture (e.g., polling for new information and then providing a corresponding response) may instead be implemented using a "push" architecture (e.g., sending such information when there is new information to report), and vice versa.

[0051] Illustrated processing block 502 provides for sensing a capacitance value of the fluid via a continuous sensor wire, for example, sensing a capacitance value associated with the fluid via a continuous sensor wire located within a tube, wherein the continuous sensor wire extends from an upper end of the tube to a lower end of the tube as described above.

[0052] Illustrated processing block 504 provides for determining a wet reference capacitance value, for example, via a wet reference wire located within the tube, where the wet reference wire extends from an upper end of the tube to a lower end of the tube as described above.

[0053] Illustrated processing block 506 provides for determining a dry reference capacitance value, for example, via a dry reference wire located within the tube, wherein the dry reference wire is positioned adjacent to the upper end of the tube as described above.

[0054] Illustrated processing block 508 provides for determining an output fluid level. For example, as described above, the output fluid level is determined based on the sensed fluid capacitance value, the wet reference capacitance value, and the dry reference capacitance value.

[0055] In some examples, method 500 further includes shielding the first covered portion of the wet-reference wire via the wet-reference shielding sheath so that a second exposed portion of the wet-reference wire is not covered by the wet-reference shielding sheath, wherein the second exposed portion of the wet-reference wire is adjacent to the lower end of the tube. In such examples, the wet-reference shielding sheath can be electrically driven.

[0056] In some implementations, method 500 further includes shielding the first covered portion of the dry reference wire via the dry reference shielding sheath so that the second exposed portion of the dry reference wire is not covered by the dry reference shielding sheath. In such examples, the dry reference shielding sheath can be electrically driven.

[0057] Another approach (not illustrated here) may generally be to use a device (such as, for example, the fluid level sensor 200 already discussed) Figure 2)) is implemented. This method includes sensing a fluid capacitance value via a continuous sensor plate of a fluid level sensor, wherein the sensor plate extends from an upper end of a substrate to a lower end of the substrate. A wet reference capacitance value is determined via a wet reference capacitance plate positioned adjacent to the lower end of the substrate. A dry reference capacitance value is determined via a dry reference capacitance plate positioned adjacent to the upper end of the substrate. An output fluid level is determined based on the sensed fluid capacitance value, the wet reference capacitance value, and the dry reference capacitance value. A trace is shielded from capacitance interference via a wet reference shield, wherein the trace and the wet reference shield extend from the upper end of the substrate to the wet reference capacitance plate.

[0058] In some examples, the wet reference shield is electrically driven.

[0059] In some implementations, the continuous sensor plate, the wet reference capacitor plate, and the dry reference capacitor plate are shielded from capacitive interference via an outer shielding layer located on an outer surface of the substrate opposite to an inner surface of the substrate where the continuous sensor plate is located.

[0060] In some examples, the fluid level sensor is adhered to the exterior of the container. In some implementations, the fluid level sensor is bent to conform to the exterior of the container.

[0061] Figure 6 The result 600 of simulation is depicted to further illustrate the operation of the embodiment of the present invention. A simulation is performed in which a container is filled with water and then drained. The x-axis (not shown) represents the liquid level in the container, and the y-axis represents the sensed value (digitized by a digital converter (not shown)). The sensed capacitance level (C-LEVEL) rises and falls with the fluid level when the container is filled and then drained. The RE as an environmental reference does not change because there is no medium in contact with it and no changes in any environmental factors (e.g., temperature) are observed. The RL as a liquid reference experiences a rise and then a fall because it is initially in contact with the medium and then loses contact with the medium, but is otherwise stable. The RE and RL work in tandem. If the medium undergoes a dielectric change (e.g., due to physically changing the medium or temperature in the container), the RL operates to compensate for the wetted portion of the C-LEVEL, and the RE operates to compensate for the unwetted portion of the C-LEVEL, which may be affected by changes in environmental conditions in the container.

[0062] Figure 7 A block diagram of an exemplary computer program product 700 is illustrated. In some examples, such as Figure 7As shown, the computer program product 700 includes a machine-readable storage device 702, which may also include computer-readable instructions 704. In some specific implementations, the machine-readable storage device 702 may be implemented as a non-transitory machine-readable storage device. In some specific implementations, for example, the computer-readable instructions 704 may be implemented as software. In an example, the computer-readable instructions 704, when executed by a processor 706, implement the method 500 discussed above ( Figure 5 )

[0063] Figure 8 An illustrative example of a device 800 is shown. In the illustrated example, the device 800 may include a processor 802 and a memory 804 communicatively coupled to the processor 802. The memory 804 may include computer readable instructions 806, which may be implemented as software, for example. In an example, the computer readable instructions 806, when executed by the processor 802, implement the method 500 discussed above ( Figure 5 )

[0064] In some implementations, the processor 802 may include a general purpose controller, a special purpose controller, a storage controller, a storage manager, a memory controller, a microcontroller, a general purpose processor, a special purpose processor, a central processing unit (CPU), etc. and / or combinations thereof.

[0065] In addition, specific implementations may include distributed processing, component / object distributed processing, parallel processing, etc. and / or combinations thereof. For example, a virtual computer system process may implement one or more of the methods or functions described herein, and the processor 802 described herein may be used to support such virtual processing.

[0066] In some examples, memory 804 is an example of a computer-readable storage medium. For example, memory 804 can be any memory accessible to processor 802, including but not limited to RAM memory, registers and register files, etc. and / or combinations thereof. References to "computer memory" or "memory" should be understood to mean that there may be multiple memories. The memory can be, for example, multiple memories within the same computer system. The memory can also be multiple memories distributed in multiple computer systems or computing devices.

[0067] Fig. 9An exemplary semiconductor device 900 (e.g., a chip and / or a package) is shown. The illustrated device 900 includes one or more substrates 902 (e.g., silicon, sapphire, or gallium arsenide) and computer-readable instructions 904 (such as configurable computer-readable instructions (e.g., firmware) and / or fixed-function computer-readable instructions (e.g., hardware)) coupled to the substrate 902. In an example, the computer-readable instructions 904 implement the method 500 discussed ( Figure 5 )

[0068] In some implementations, the computer readable instructions 904 may include transistor arrays and / or other integrated circuit (IC) components. For example, the configurable firmware logic and / or fixed-function hardware logic implementation of the computer readable instructions 904 may include: configurable computer readable instructions, such as, for example, a programmable logic array (PLA), a field programmable gate array (FPGA), a complex programmable logic device (CPLD); or fixed-function computer readable instructions (e.g., hardware) that use circuit technology, such as, for example, an application specific integrated circuit (ASIC), a complementary metal oxide semiconductor (CMOS), or a transistor-transistor logic (TTL) technology, etc.; and / or combinations thereof.

[0069] Additional Notes and Examples:

[0070] Item 1 is a fluid level sensor, comprising: a tube; a continuous sensor wire, the continuous sensor wire being located within the tube, wherein the continuous sensor wire extends from an upper end of the tube to a lower end of the tube; a grounding wire, the grounding wire being located within the tube, wherein the grounding wire extends from the upper end of the tube to the lower end of the tube; a wet reference wire, the wet reference wire being located within the tube, wherein the wet reference wire extends from the upper end of the tube to the lower end of the tube; and a dry reference wire, the dry reference wire being located within the tube, wherein the dry reference wire is positioned adjacent to the upper end of the tube.

[0071] Item 2 includes a fluid level sensor according to Item 1, wherein the fluid level sensor also includes a wet reference shielding sheath, wherein the wet reference shielding sheath is located on the first covered portion of the wet reference wire so that a second exposed portion of the wet reference wire is not covered by the wet reference shielding sheath, and wherein the second exposed portion of the wet reference wire is adjacent to the lower end of the tube.

[0072] Clause 3 includes the fluid level sensor of clause 2, wherein the wet reference shield is electrically driven.

[0073] Item 4 includes a fluid level sensor according to any one of items 1 to 3, wherein the fluid level sensor also includes a dry reference shielding sheath, wherein the dry reference shielding sheath is located on the first covered portion of the dry reference wire so that the second exposed portion of the dry reference wire is not covered by the dry reference shielding sheath.

[0074] Clause 5 includes the fluid level sensor of clause 4, wherein the dry reference shield is electrically driven.

[0075] Clause 6 includes the fluid level sensor of any of clauses 1 to 5, wherein the continuous sensor wire, the ground wire, the wet reference wire, and the dry reference wire are all flexible.

[0076] Clause 7 includes the fluid level sensor of any one of clauses 1 to 6, wherein the continuous sensor wire, the ground wire, the wet reference wire, and the dry reference wire are all coated with a wire sheath to electrically isolate each wire.

[0077] Item 8 includes a fluid level sensor, comprising: a substrate; a continuous sensor plate, the continuous sensor plate being located on the substrate, wherein the continuous sensor plate extends from an upper end of the substrate to a lower end of the substrate; a continuous ground plate, the continuous ground plate being located on the substrate, wherein the continuous ground plate extends from the upper end of the substrate to the lower end of the substrate; a wet reference capacitor plate, the wet reference capacitor plate being located on the substrate, wherein the wet reference capacitor plate is positioned adjacent to the lower end of the substrate; and a dry reference capacitor plate, the dry reference capacitor plate being located on the substrate, wherein the dry reference capacitor plate is positioned adjacent to the upper end of the substrate.

[0078] Clause 9 includes the fluid level sensor of clause 8, wherein the substrate is flexible.

[0079] Clause 10 includes the fluid level sensor of any of clauses 8 to 9, wherein the substrate is rigid.

[0080] Item 11 includes a fluid level sensor according to any one of items 8 to 10, wherein the fluid level sensor further includes: a trace extending from the upper end of the substrate to the wet reference capacitor plate; and a wet reference shield positioned adjacent to the trace, wherein the wet reference shield extends from the upper end of the substrate to the wet reference capacitor plate.

[0081] Clause 12 includes the fluid level sensor of clause 11, wherein the wet reference shield is electrically driven.

[0082] Item 13 includes a fluid level sensor according to any one of items 8 to 12, wherein the fluid level sensor also includes an external shielding layer, which is located on the outer surface of the substrate, the outer surface is opposite to the inner surface of the substrate where the continuous sensor plate is located, and wherein the external shielding layer is composed of copper.

[0083] Clause 14 includes the fluid level sensor of clause 13, further comprising a capacitance-to-digital converter located on the outer surface of the substrate in a gap formed in the outer shield layer.

[0084] Clause 15 includes the fluid level sensor of any of clauses 8 to 14, further comprising a tube located around the fluid level sensor.

[0085] Item 16 includes a method comprising: sensing a fluid capacitance level via a continuous sensor wire located within a tube, wherein the continuous sensor wire extends from an upper end of the tube to a lower end of the tube; determining a wet reference capacitance value via a wet reference wire located within the tube, wherein the wet reference wire extends from the upper end of the tube to the lower end of the tube; determining a dry reference capacitance value via a dry reference wire located within the tube, wherein the dry reference wire is positioned adjacent to the upper end of the tube; and determining an output fluid level based on the sensed fluid capacitance level, the wet reference capacitance value, and the dry reference capacitance value.

[0086] Clause 17 includes the method according to clause 16, further comprising: shielding a first covered portion of the wet reference wire via a wet reference shielding sheath so that a second exposed portion of the wet reference wire is not covered by the wet reference shielding sheath, and wherein the second exposed portion of the wet reference wire is adjacent to the lower end of the tube.

[0087] Clause 18 includes the method of clause 17, wherein the wet-reference shield is electrically driven.

[0088] Clause 19 includes the method of any one of clauses 16 to 18, further comprising shielding a first covered portion of the dry reference wire via a dry reference shielding sheath so that a second exposed portion of the dry reference wire is not covered by the dry reference shielding sheath.

[0089] Clause 20 includes the method of clause 19, wherein the dry reference shielding sheath is electrically driven.

[0090] Item 21 includes a method comprising: sensing a fluid level via a continuous sensor plate of a fluid level sensor, wherein the sensor plate extends from an upper end of a substrate to a lower end of the substrate; determining a wet reference value via a wet reference capacitor plate positioned adjacent to the lower end of the substrate; determining a dry reference value via a dry reference capacitor plate positioned adjacent to the upper end of the substrate; determining an output fluid level based on the sensed level, the wet reference value, and the dry reference value; and shielding a trace from capacitive interference via a wet reference shield, wherein the trace and the wet reference shield extend from the upper end of the substrate to the wet reference capacitor plate.

[0091] Clause 22 includes the method of clause 21, wherein the wet reference shield is electrically driven.

[0092] Clause 23 includes a method according to any one of clauses 21 to 22, further comprising: shielding the continuous sensor plate, the wet reference capacitor plate and the dry reference capacitor plate from capacitive interference via an external shielding layer, wherein the external shielding layer is located on an outer surface of the substrate, and the outer surface is opposite to the inner surface of the flexible substrate where the continuous sensor plate is located.

[0093] Clause 24 includes the method of any one of clauses 21 to 23, further comprising adhering the fluid level sensor to an exterior of a container.

[0094] Clause 25 includes the method of clause 24, further comprising bending the fluid level sensor to conform to the exterior of the container.

[0095] Clause 26 comprises a machine-readable storage device comprising machine-readable stored instructions which, when executed, perform a method according to any preceding clause or implement an apparatus according to any preceding clause.

[0096] Clause 27 includes an apparatus comprising means for performing the functions according to any preceding clause.

[0097] All definitions, as defined and used herein, should be understood to control over dictionary definitions, definitions in documents incorporated by reference, and / or ordinary meanings of the defined terms.

[0098] In addition, for ease of understanding, some functional blocks may be depicted as separate blocks; however, these separately depicted blocks should not be understood to be in the order in which they are discussed or otherwise presented herein. For example, some blocks may be able to be executed in an alternative order, simultaneously, etc.

[0099] As used herein, phrases substantially similar to "at least one of A, B, or C" are intended to be interpreted as disjunctive, i.e., requiring A or B or C or any combination thereof, unless the context indicates or implies otherwise. Further, phrases substantially similar to "at least one of A, B, and C" are intended to be interpreted as conjunctions, i.e., requiring at least one of A, at least one of B, and at least one of C, unless the context indicates or implies otherwise. Still further, the term "substantially" or similar words requiring a subjective comparison are intended to mean "within manufacturing tolerances," unless the context indicates or implies otherwise.

[0100] As used herein, the terms "coupled," "attached," "connected," or "operably connected" may be used herein to refer to any type of direct or indirect relationship between the components being discussed. For example, the terms "coupled," "attached," "connected," or "operably connected" may refer to at least a functional relationship between two elements, and may cover configurations in which two elements are directly connected to each other (i.e., without any intervening elements) or indirectly connected to each other (i.e., with intervening elements). In addition, the terms "first," "second," etc., are used herein only to facilitate discussion and do not have a specific temporal or chronological meaning unless otherwise indicated. The terms "cause" or "causing" mean to instruct, force, prompt, guide, command, indicate, and / or enable an event or action to occur or at least to be in a state in which such an event or action can occur in a direct or indirect manner.

[0101] Although a number of illustrative examples are described herein, it will be appreciated that those skilled in the art may devise many other modifications and examples that will fall within the spirit and scope of the principles disclosed above. More specifically, reasonable variations and modifications in the components and / or arrangements of the subject combination arrangements are possible within the scope of the foregoing disclosure, the accompanying drawings, and the appended claims without departing from the spirit of the foregoing disclosure. In addition to variations and modifications of the components and / or arrangements, alternative uses will be apparent to those skilled in the art. These examples may be combined to form additional examples.

Claims

1. A fluid level sensor, comprising: Tube; a continuous sensor wire located within the tube, wherein the continuous sensor wire extends from an upper end of the tube to a lower end of the tube; a grounding conductor, the grounding conductor being located within the tube, wherein the grounding conductor extends from the upper end of the tube to the lower end of the tube; a wet reference wire located within the tube, wherein the wet reference wire extends from the upper end of the tube to the lower end of the tube; and A dry reference wire is positioned within the tube, wherein the dry reference wire is positioned adjacent the upper end of the tube.

2. The fluid level sensor of claim 1 further comprising a wet reference shielding sheath positioned over the first covered portion of the wet reference wire so as to leave a second exposed portion of the wet reference wire uncovered by the wet reference shielding sheath, and wherein the second exposed portion of the wet reference wire is adjacent to the lower end of the tube.

3. The fluid level sensor of claim 2, wherein the wet reference shield is electrically driven.

4. The fluid level sensor of claim 1 further comprising a dry reference shielding sheath positioned over the first covered portion of the dry reference wire so that a second exposed portion of the dry reference wire is not covered by the dry reference shielding sheath.

5. The fluid level sensor of claim 4, wherein the dry reference shield is electrically driven.

6. The fluid level sensor of claim 1, wherein the continuous sensor wire, the ground wire, the wet reference wire, and the dry reference wire are all flexible.

7. The fluid level sensor of claim 1, wherein the continuous sensor wire, the ground wire, the wet reference wire, and the dry reference wire are all coated with a wire sleeve to electrically isolate each wire.

8. A fluid level sensor, comprising: substrate; a continuous sensor plate, the continuous sensor plate being located on the substrate, wherein the continuous sensor plate extends from an upper end of the substrate to a lower end of the substrate; a continuous ground plate, the continuous ground plate being located on the substrate, wherein the continuous ground plate extends from the upper end of the substrate to the lower end of the substrate; a wet reference capacitive plate located on the substrate, wherein the wet reference capacitive plate is positioned adjacent the lower end of the substrate; and A dry reference capacitive plate is located on the substrate, wherein the dry reference capacitive plate is positioned adjacent to the upper end of the substrate.

9. The fluid level sensor of claim 8, wherein the substrate is flexible.

10. The fluid level sensor of claim 8, wherein the substrate is rigid.

11. The fluid level sensor according to claim 8, further comprising: a trace extending from the upper end of the substrate to the wet reference capacitor plate; and A wet reference shield is positioned adjacent to the trace, wherein the wet reference shield extends from the upper end of the substrate to the wet reference capacitive plate.

12. The fluid level sensor of claim 11, wherein the wet reference shield is electrically driven.

13. The fluid level sensor of claim 8, further comprising an outer shielding layer located on an outer surface of the substrate, the outer surface being opposite to an inner surface of the substrate on which the continuous sensor plate is located, and wherein the outer shielding layer is comprised of copper.

14. The fluid level sensor of claim 13, further comprising a capacitance-to-digital converter located on the outer surface of the substrate in a gap formed in the outer shield layer.

15. The fluid level sensor of claim 8, further comprising a tube positioned around the fluid level sensor.

16. A method comprising: sensing the fluid capacitance level via a continuous sensor wire located within the tube, wherein the continuous sensor wire extends from an upper end of the tube to a lower end of the tube; determining a wet reference capacitance value via a wet reference wire located within the tube, wherein the wet reference wire extends from the upper end of the tube to the lower end of the tube; determining a dry reference capacitance value via a dry reference wire located within the tube, wherein the dry reference wire is located adjacent the upper end of the tube; as well as An output fluid level is determined based on the sensed fluid capacitance level, the wet reference capacitance value, and the dry reference capacitance value.

17. The method according to claim 16, further comprising: A first covered portion of the wet reference wire is shielded via a wet reference shielding sheath such that a second exposed portion of the wet reference wire is not covered by the wet reference shielding sheath, and wherein the second exposed portion of the wet reference wire is adjacent to the lower end of the tube.

18. The method of claim 17, wherein the wet reference shield is electrically driven.

19. The method according to claim 16, further comprising: The first covered portion of the dry reference wire is shielded via a dry reference shielding sheath such that a second exposed portion of the dry reference wire is not covered by the dry reference shielding sheath.

20. The method of claim 19, wherein the dry reference shielding sheath is electrically driven.

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