Capacitive sensing rotary encoder

Abstract

An apparatus is provided that includes a rotary encoder that includes a stator (214), a rotor (212), and a controller (218). The stator (214) has an opening adapted to surround a first portion of a rotatable shaft (210), a transmitting region, and a receiving region. The rotor (212) has an opening adapted to surround a second portion of the rotatable shaft (210), an annular conductive region, and at least one conductor electrically coupled to the annular conductive region. The controller (218) has an input coupled to the receiving region and has an output coupled to the transmitting region. The controller (218) is configured to transmit a first signal on the output of the controller (218) and to the transmitting region of the stator (214), to receive a second signal on the input of the controller (218) and from the receiving region of the stator (214), and to determine a proximity of the at least one conductor to the receiving region based on the second signal.

Description

Background Technology

[0001] Flow meters, such as gas meters, water meters, and electricity meters, track the amount of fluid or energy that has flowed through them. Flow meters can also use manual indicators, such as one or more digital wheels, to indicate the amount of fluid or energy used since the initial value. Summary of the Invention

[0002] According to one aspect, an apparatus includes a rotary encoder comprising a stator, a rotor, and a controller. The stator has: an opening adapted to surround a first portion of a rotatable shaft; a transmitting region located on a first concentric region of the stator; and a receiving region located on a second concentric region of the stator. The second concentric region of the stator is separate from the first concentric region of the stator. The rotor has: an opening adapted to surround a second portion of the rotatable shaft; an annular conductive region located on the first concentric region of the rotor; and at least one conductor electrically coupled to the annular conductive region and located on the second concentric region of the rotor. The second concentric region of the rotor is separate from the first concentric region of the rotor. The controller has an input coupled to the receiving region and an output coupled to the transmitting region. The controller is configured to transmit a first signal at its output and to the transmitting region of the stator, receive a second signal at its input and from the receiving region of the stator, and determine the proximity of the at least one conductor to the receiving region based on the second signal.

[0003] According to another aspect, an apparatus includes: a rotatable shaft; a rotor coupled to a first portion of the rotatable shaft; and a fixed base plate positioned adjacent to the rotor. The rotor includes: a central region located on a first concentric region of the rotor; and at least one blade coupled to and extending from the central region, the at least one blade located on a second concentric region of the rotor. The fixed base plate has: an opening surrounding the rotatable shaft; a transmitting region configured to be capacitively coupled to the central region; and a capacitive sensor array configured to be capacitively coupled to the at least one blade. The apparatus further includes a controller electrically coupled to the transmitting region and the capacitive sensor array, and configured to receive an output from the capacitive sensor array based on a signal transmitted to the transmitting region, and to determine an angular rotation of the rotor based on the output.

[0004] According to another aspect, a method of manufacturing a rotary encoder includes: coupling a rotor to a rotatable shaft; positioning the rotor adjacent to a stator having an opening adapted to surround a second portion of the rotatable shaft; and coupling a controller to a transmitting region and a receiving region. The rotor has: an opening adapted to surround a first portion of the rotatable shaft; an annular conductive region located on a first concentric region of the rotor; and at least one conductor electrically coupled to the annular conductive region and located on a second concentric region of the rotor, the second concentric region being separate from the first concentric region. The stator includes: a transmitting region located on the first concentric region of the stator; and a receiving region located on the second concentric region of the stator, the second concentric region being separate from the first concentric region. The controller is configured to transmit a first signal to the transmitting region of the stator, receive a second signal from the receiving region of the stator, and determine the proximity of at least one conductor to the receiving region based on the second signal. Attached Figure Description

[0005] In the attached diagram:

[0006] Figure 1 This is a block diagram of an example flow meter assembly having a capacitive sensing rotary encoder assembly according to this disclosure.

[0007] Figure 2 This is an isometric view of a sample flow meter as disclosed herein.

[0008] Figure 3 This is a schematic diagram of an example stator PCB based on this disclosure.

[0009] Figure 4 This is a schematic diagram of rotating a PCB according to an example disclosed herein.

[0010] Figure 5 Based on this disclosure Figure 1 A side view of an example section of an example PCB component.

[0011] Figure 6 Based on this disclosure Figure 1 A side view of an example section of an example PCB component.

[0012] Figure 7 This is a schematic diagram of a sample flow meter as part of this disclosure.

[0013] Figure 8 This disclosure is applicable to implementation. Figure 1 A schematic diagram of an example sensing circuit.

[0014] Figure 9 This disclosure is applicable to implementation. Figure 1Another example of a sensing circuit is shown in the schematic diagram.

[0015] Figure 10 This disclosure is applicable to implementation. Figure 1 A schematic diagram of another example sensing circuit.

[0016] Figure 11 This is a flowchart of the counter decoding scheme disclosed herein. Detailed Implementation

[0017] Figure 1 This is a block diagram of an example flowmeter assembly 100 having an input 102 and an output 104. In a fluid-based flowmeter, a fluid, such as a liquid or gas, flows from the input 102 to the output 104, while the flowmeter assembly 100 measures the amount of fluid passing through it. Between the input 102 and the output 104, a counter driver 106 is positioned in flow communication with the fluid passing through the flowmeter assembly 100. The counter driver 106 may include mechanical conversion devices to convert the fluid flowing through or passing through it into rotational motion. For example, the counter driver 106 may include one or more gears configured to rotate in response to fluid flow. In an electrically powered flowmeter, an electric current flowing between the input 102 and the output 104 causes the electrically powered counter driver 106 to convert the electrical power into mechanical motion, thereby causing one or more gears to rotate.

[0018] Counter assembly 108 is coupled to counter driver 106 to visually indicate the cumulative total amount of fluid or energy that has flowed through flowmeter assembly 100 since an initial value (e.g., 0). Counter assembly 108 may include one or more digital wheels that rotate in response to counter driver 106. Counter assembly 108 may be, for example, a decimal counter having individual decimal digital wheels with the numbers 0 to 9 embossed along the circumferential surface of each wheel. The rotation lines of the digital wheels are aligned with each other, and the wheels may be coupled in such a way that a full rotation of one wheel causes a portion of the adjacent wheel to rotate. In this way, a full rotation of the units digit wheel causes the tens digit wheel to rotate one-tenth of a rotation to its next digit. Each subsequent wheel is coupled to the previous wheel in the same manner.

[0019] According to this disclosure, a capacitive rotary encoder assembly 110 is coupled to a counter assembly 108. The capacitive rotary encoder assembly 110 includes a printed circuit board (PCB) assembly 112, which includes a rotor PCB assembly 114 on which conductors 116 are implemented, and a stator PCB assembly 118 on which a rotary encoder 120 is implemented. The rotor PCB assembly 114 includes one rotor PCB for each digital wheel of the counter assembly 108, and each rotor PCB is configured to rotate simultaneously with its adjacent corresponding digital wheel.

[0020] The stator PCB assembly 118 includes a stator PCB for each rotor PCB of the rotor PCB assembly 114. As disclosed in more detail below, as each rotor PCB rotates relative to its corresponding stator PCB, the rotor PCB changes the capacitance of the sensing capacitor of the stator PCB.

[0021] Figure 2 This is an isometric view of a portion of an example flow meter 200 according to the example. The counter assembly 202 and viewing panel 204 of the flow meter 200 are shown. The counter assembly 202 includes a plurality of digit wheels 206 arranged about an axis 210 along a common axis of rotation 208. In the illustrated example, six digit wheels 206 are shown. However, more or fewer than six digit wheels 206 are contemplated herein. The six digit wheels 206 may have the same markings on their outer cylindrical surfaces, or they may have different markings on one or more of the wheels 206. When marked with the numbers 0 to 9, the counter assembly 202 can operate as a decimal counter, where each wheel 206 rotates 10 times for every one rotation of its adjacent left-hand wheel.

[0022] Multiple rotors 212 are attached to multiple digital wheels 206, each rotor 212 being coupled to rotate together with a corresponding wheel 206. Multiple stators 214 are provided, each stator 214 being positioned adjacent to a corresponding rotor 212. A base or substrate 216 provides support for the stators 214. According to an example of this disclosure, the rotors 212, stators 214, and base 216 are constructed from one or more PCB materials on which electrical traces are formed.

[0023] Figure 3 This is a schematic diagram of the example stator PCB 300. The stator PCB 300 can be used for implementation. Figure 1 An example rotary encoder 120 includes a substrate 302 constructed of one or more PCB materials. An opening 304 may be provided in the substrate 302 to allow a shaft or other object to extend through the substrate 302 (e.g., see...). Figure 7 ).

[0024] The stator PCB 300 includes a circular capacitive sensor array 306 comprising a plurality of capacitive sensing regions or receiving conductors arranged around a first concentric region 310 of the substrate 302 (for the example capacitive sensing array 306, one of these plurality of capacitive sensing regions or receiving conductors is indicated by reference numeral 308). As shown, the capacitive sensing regions 308 within the capacitive sensor array 306 are angularly offset or separated from each other about the axis of rotation 312 of the stator PCB 300 and are electrically decoupled from each other. The capacitive sensing regions 308 implement the receiving regions or combined sensing capacitors of the capacitive sensor array 306. Although Figure 3 The plurality of capacitive sensing regions 308 shown provide ten sensing regions for implementation in a decimal counter, but, for example, the plurality of sensing regions 308 may include more or fewer regions to match each wheel (e.g., Figure 2 The number wheel 206 has multiple indicators, which may be more or less than ten.

[0025] The stator PCB 300 also includes a emitter region 314 arranged around a second concentric region 316 of the substrate 302 and a ground region 318 arranged around a third concentric region 320 of the substrate 302. In the illustrated example, the second concentric region 316 is closer to the opening 304 than the first concentric region 310, and the third concentric region 320 is located between the first concentric region 310 and the second concentric region 316. However, in another example, the positions of the first concentric region 310 and the second concentric region 316 may be interchanged.

[0026] The emitter region 314, ground region 318, and capacitive sensing region 308 of the capacitive sensor array 306 can be constructed from conductive traces, pads, and / or areas on the substrate 302, such as from copper or other PCB metal trace materials. The substrate 302 includes a plurality of sensor array contact pads 322, each pad 322 being electrically coupled to a corresponding capacitive sensing region 308. The substrate 302 also includes a ground contact pad 324 electrically coupled to the ground region 318, and an emitter contact pad 326 electrically coupled to the emitter region 314. As illustrated, regions 308, 314, and 318 are formed on the same side of the substrate 302. As shown, pads 322, 324, and 326 may further be formed on the same side, or some or all may be mounted on opposite sides to accommodate trace wiring or to accommodate connectors on the substrate 302 to which pads 322, 324, and 326 can be coupled / soldered. For example, six of the pads 322, 324, and 326 shown may be formed on one side of the substrate 302, while the remaining six may be formed on the other side of the substrate 302. Additionally, one or more vias 328 may be implemented to move any portion of the trace to the opposite side of the substrate 302.

[0027] Figure 4 It can be used for implementation Figure 1 A schematic diagram of an example rotating PCB 400 for example rotor PCB assembly 114. The rotating PCB 400 includes a substrate 402 constructed of one or more PCB materials. An opening 404 may be provided in the substrate 402 to allow a shaft or other object to extend through the substrate 402 (e.g., see...). Figure 7 ).

[0028] The substrate 402 has a shaped conductor member 406 formed thereon, the shaped conductor member including a conductive region 408 arranged around a first concentric region 410. In one example as shown, the conductive region 408 is annular and surrounds an opening 404. A pair of blades or conductors 412, 414 of the conductor member 406 are electrically coupled to and extend from the conductive region 408. The conductors 412, 414 are centrally positioned on a second concentric region 416 and are angularly separated and offset from each other about a central axis of rotation 418 of the rotating PCB 400.

[0029] During operation, the rotating PCB 400 rotates relative to the stator PCB 300. When conductors 412 and 414 overlap with the corresponding capacitive sensing areas 308, the capacitance of the corresponding capacitive sensing areas 308 will be modified due to the proximity of the conductor members 406.

[0030] Figure 5The illustration shows a capacitance formed by a capacitive sensing region 308 and a ground region 318 formed on a substrate 302 of a stator PCB 300. The ground region 318 is spaced apart from the capacitive sensing region 308 (e.g., not in physical contact, not in electrical contact, etc.) to form an example electric field 500 when a signal is emitted to and present in the emitting region 314. An annular conductive region 408 always overlaps with the emitting region 314 and the ground region 318. However, as the PCB 400 rotates about its axis of rotation 418, conductors 412, 414 (…) are alternately spaced around a second concentric region 416 of the rotating PCB 400… Figure 4 It periodically overlaps with any particular capacitive sensing region 308. Figure 5 In the example illustrated, neither conductor 412 nor 414 is rotated to overlap with the capacitive sensing region 308. Therefore, the electric field 502 between the capacitive sensing region 308 and the ground region 318 indicates the capacitance value representing the absence of conductors 412 and 414 adjacent to the capacitive sensing region 308. In one example, the electric field 502 represents the default or baseline capacitance measurable during initial calibration testing.

[0031] As the rotating PCB 400 rotates, conductors 412 and 414 can move into, through, and out of the electric field 502. When at least part of one of the conductors 412 and 414 is above or near the electric field 502 (e.g., close to the electric field), the conductors 412 and 414 interfere with the electric field 502, thereby increasing the capacitance of the capacitive sensing region 308. Figure 6 The illustration shows the capacitance formed by the capacitive sensing region 308 and the ground region 318 when one of the conductors 412 and 414 is adjacent to and overlaps with the capacitive sensing region 308. As illustrated, the modified electric field 504 indicates the capacitance value experienced when the capacitive sensing region 308 and the ground region 318 are very close to one of the conductors 412 and 414.

[0032] When the transmitted signal is sent to transmission area 314, it forms Figure 5 and Figure 6 The diagram shows electric fields 500, 502, and 504. (Return to reference) Figure 2An integrated circuit (IC) 218 ​​located on base 216 includes, for example, an output 220 configured to be coupled to emitter regions 314 of a plurality of stators 214. As further described below, IC 218 transmits a transmit signal to the emitter regions 314 to collect capacitance values. Output 220 may include different electrical connections to each emitter region 314 of the plurality of stators 214, or may be implemented in a multiplexing manner. IC 218 further includes inputs 222 of a capacitive sensor array 306 coupled to the plurality of stators 214. Like output 220, input 222 of IC 218 may include different electrical connections to each emitter region 314 of the plurality of stators 214, or may be implemented in a multiplexing manner.

[0033] The observation panel 204, positioned close to the counter assembly 202, allows the counter assembly 202 to be seen through a portion of the outer housing (not shown) into which it is placed. Indicators 224 on the observation panel 204 can be aligned with a plurality of digital wheels 206 to visually indicate the value of the counter assembly 202.

[0034] Figure 7 A schematic diagram of a portion of an example flowmeter assembly 700 according to this disclosure is illustrated. As illustrated, three digital wheel assemblies 702, 704, and 706 are assembled together in a counter assembly 708. A digital wheel 710 of digital wheel assembly 702 is fixedly coupled to a rotating PCB 712, and one or both of digital wheels 710 and rotating PCB 712 are fixedly coupled to a shaft 714 passing through it. Therefore, digital wheels 710, shaft 714, and rotating PCB 712 rotate in unison. Digital wheel assemblies 704 and 706 also include corresponding digital wheels 716 and 718 fixedly coupled to corresponding rotating PCBs 720 and 722, such that rotation of digital wheel 716 causes the same rotation in rotating PCB 720, and rotation of digital wheel assembly 718 causes the same rotation in rotating PCB 722. Digital wheels 716 and 718 also include channels or orifices (not shown) formed therein to allow shaft 714 to pass through. However, unlike the digital wheel assembly 702, the digital wheels 716 and 718 are not fixedly attached to the shaft 714, but are allowed to rotate independently of the shaft.

[0035] A counter driver 724 coupled to shaft 714 causes shaft 714, digital wheel 710, and the rotating PCB 712 attached thereto to rotate based on the flow of fluid or energy through flowmeter assembly 700. For example, flow to rotating assembly 726 can be directly coupled to shaft 714 or coupled via gear assembly 728. Counter driver 724 is designed to convert fluid or energy flow into rotational motion, which causes shaft 714 to rotate and thus causes first digital wheel 710 to rotate. Digital wheel 710 includes gear engagement member 730, which is configured to cause partial rotation of gear 732 positioned adjacent to first digital wheel 710 and second digital wheel 716. Rotation of gear 732 causes partial rotation of digital wheel 716. Thus, each rotation of digital wheel 710 causes partial rotation in digital wheel 716 via gear 732. According to one example, ten rotations of digital wheel 710 cause one full rotation of digital wheel 716. Similarly, the gear engagement member 734 on the number wheel 716 is engaged with the gear 736 adjacent to the second number wheel 716 and the third number wheel 718. According to the example provided herein, ten rotations of the number wheel 716 cause one full rotation of the number wheel 718.

[0036] Each digital wheel assembly 702, 704, 706 also includes a corresponding stator PCB 738, 740, 742, each stator PCB coupled to a substrate 744 having an IC 746 configured to determine the angular rotation of digital wheels 710, 716, 718 based on determining multiple capacitance values ​​experienced by the stator PCBs 738, 740, 742. The stator PCBs 738, 740, 742 may also include openings, such as opening 304. Figure 3 An opening (not shown) is formed to allow shaft 714 to pass through it. Additionally, an opening (not shown) formed to allow gears 732, 736 and their common shaft 748 to pass through may be formed according to the arrangement.

[0037] Figure 8 This is a schematic diagram of an example sensing circuit 800, which is a combined sensing capacitor 802 of a capacitive sensor array 306 in the form of an oscillator circuit. The example sensing circuit 800 can be used to implement example sensing circuitry embedded within IC 218 or otherwise accessible to that IC. When control input 804 is set to logic high (e.g., equal to the supply voltage Vcc), the example resistor ladder network 806 creates an example reference input 808 for the example comparator 810, which changes with the example output 812 of comparator 810. The example reference input 808 switches and has the opposite polarity to the charging and discharging of the capacitive sensor 802. Figure 8In the example, if the resistors R in the resistor ladder network 806 have approximately equal resistances, then the oscillation or period frequency f of the output 812 of the comparator 810 will be... OSC This can be expressed mathematically as: f osc =1 / (1.386R) c C 传感器 ), Where C 传感器 This is the capacitance of the capacitive sensor 802, which changes in response to the proximity of a conductor (such as example conductor member 406). As described above... Figures 3 to 6 As discussed, when the conductors interfere with the electric fields 502 and 504, the capacitance of the capacitive sensor 804 increases, and therefore, the period frequency f of the output 812 of the comparator 810 increases. OSC Increase. That is, the period frequency f OSC It can be used to measure the capacitance of the capacitive sensor 802.

[0038] In order to determine (e.g., estimate, measure, etc.) the period frequency f of the output signal 812 of comparator 810 OSC The example sensing circuit 800 includes an example counter 820 and an example count register 830. The example counter 820 counts the periods of the output signal 812 by, for example, counting the rising or falling edges of the output 812. At periodic intervals, the current period count is stored in the example count register 830 for subsequent retrieval, and the counter 820 is reset. The larger the count stored in the count register 830, the higher the period frequency f of the output 812. OSC The higher the capacitance, and the greater the capacitance of the capacitive sensor 802, the greater the interference from the conductor on the capacitive sensor 802.

[0039] Figure 9 This is a schematic diagram of another example sensing circuit 900, which is a combined sensing capacitor 902 in the form of a charge transfer circuit, representing a capacitive sensor array 306. Figure 9 The example sensing circuit 900 can be used to implement example sensing circuitry embedded within IC 218 or otherwise accessible to the IC. Figure 9 In this circuit, a resistor-capacitor (RC) network 904 is used to charge the circuit voltage 906. Controlled by signals 908 using control example switches SW1 and SW2, charge is periodically transferred from the sensing capacitor 902 to the RC network 904. When a conductor approaches the capacitive sensor 902, the capacitance of the capacitive sensor 902 increases, and in each cycle of signal 908, more charge is transferred from the capacitive sensor 902 to the RC network 904. The circuit voltage 906 is increased beyond a threshold voltage V by counting using a counter 910. REFThe number of cycles of the required signal 908 determines a measure of the capacitance of the capacitive sensor 902. At periodic intervals, the current count is stored in the example count register 912 for subsequent retrieval, and the counter 910 is reset. The smaller the count stored in the count register 902, the larger the capacitance of the capacitive sensor 904, indicating a greater disturbance to the capacitive sensor 904 by a conductor.

[0040] Figure 10 This is another example of a combined sensing capacitor 1002 in the form of a capacitive sensor array 306 in the form of a sigma-delta sensing circuit, and is a schematic diagram of a sensing 1000. Figure 10 The example sensing circuit 1000 can be used to implement example sensing circuits embedded within IC 218 or otherwise accessible to the IC. Figure 10 In this circuit, capacitive sensor 1002 charges a resistor-capacitor (RC) network 1004 that charges circuit voltage 1006. When a conductor approaches capacitive sensor 1002, the capacitance of capacitive sensor 1002 increases, and charge is transferred from capacitive sensor 1002 to circuit voltage 1006 more quickly. Once circuit voltage 1006 exceeds a threshold reference voltage V... REF Comparator 1008 trips, and circuit voltage 1006 begins discharging through resistor 1010. As the capacitance of capacitive sensor 1002 increases, the discharge slows down as charging by capacitive sensor 1002 continues. The capacitance of capacitive sensor 1002 can be determined by counting the number of cycles of the output signal 1014 of oscillator 1016 using counter 1012 until the discharge is complete. At periodic intervals, the current count is stored in a count register 1018 for subsequent retrieval, and counter 1012 is reset. The larger the count stored in count register 1018, the larger the capacitance of capacitive sensor 1002, indicating a greater disturbance to capacitive sensor 1002 by a conductor.

[0041] Figure 11 According to the example, it can be made by a microcontroller or IC (e.g., Figure 2 The flowchart illustrates the counter decoding scheme 1100 executed by IC 218. The counter decoding scheme 1100 can be executed to determine a counter component (e.g., IC 218) having one or more digital wheels. Figure 1 , Figure 2 , Figure 7 The IC reads calibration parameters from a set of calibration parameters stored in a computer-readable storage device (step 1102). The calibration parameters may include a lookup table and have each capacitive sensing area of ​​each stator PCB of the counter assembly (e.g., ...). Figure 3The default capacitance value of the capacitive sensing area 308 of the stator PCB 300. For example, calibration parameters can be measured and stored during the manufacturing process of the counter assembly, and can include the capacitance value when the rotor conductor (e.g., Figure 4 The calibration parameters may include the sensing capacitance value of each capacitive sensing region when conductors 412 and 414 do not overlap with the capacitive sensing region. Furthermore, the calibration parameters may include the sensing capacitance value of each capacitive sensing region when one or both rotor conductors overlap with the capacitive sensing region. In this manner, as described below, during the counter decoding scheme 1100, the default or baseline capacitance value of each capacitive sensing region can be stored and used for normalization.

[0042] Set the first round to be decoded (“decoding round”) (step 1104), and this first round can be the most significant bit round (e.g., the round at the thousands place in a three-digit counter), the least significant bit round (e.g., the round at the units place in a three-digit counter), or any round in between. For the decoding round to be decoded, the corresponding stator is used to acquire capacitance value measurements from its capacitive sensor array. Scheme 1100 enables (step 1106) the transmit (“TX”) pin on the stator of the decoding round by transmitting a voltage signal from the IC performing Scheme 1100 to the transmit area of ​​the stator. From each capacitive sensing area on the stator (e.g., Figure 3 The capacitance measurement result is obtained from the capacitive sensing area 308 (step 1108). The capacitance measurement result may include determining the capacitance value on each capacitive sensing area, for example, such as Figures 8 to 10 As described in [the text].

[0043] Each of the acquired capacitance measurements is normalized based on calibration parameters (step 1110). Normalization may include identifying the difference between the most recently measured capacitance value and the calibrated capacitance value from the calibration parameters. The capacitance measurements are analyzed to identify (step 1112) one or more maximum capacitance values. The number of blades (e.g., conductors) of the rotor's conductor member indicates the number of larger capacitance values ​​that can be identified. In one example, for the embodiment described herein where the double-bladed conductor member 406 includes two conductors 412, 414, two maximum values ​​can be determined.

[0044] The rotor's angular rotation or position is determined based on (multiple) maximum capacitance values ​​(step 1114). When the rotor has a single conductor blade, the rotor's angular rotation or position can be determined as the position corresponding to the location of the capacitive sensing area that senses the maximum value. When the rotor has multiple conductor blades, multiple capacitive sensing areas sense larger capacitance values. In this case, the rotor's angular rotation or position can be determined based on the angular offset of the capacitive sensing area that senses the larger value associated with the angular offset of the multiple conductor blades. When fixed to a rotating axis (e.g., Figure 2 When the rotor is rotated (axis 210), the determination of the rotor's angular rotation or position is associated with the angular rotation or position of the axis. In one example, when the rotor is rotated such that the first conductor (e.g., conductor 412) is aligned with the first capacitive sensing area and the second conductor (e.g., conductor 414) is aligned with the fourth capacitive sensing area, the rotor's rotation angle can be known as a value, such as 0 degrees. For example, when the first conductor is aligned with the second capacitive sensing area and the second conductor is aligned with the fifth capacitive sensing area, the rotor's rotation angle can be known as 36 degrees. Other rotation angles of the rotor are also known.

[0045] Based on which number or symbol is indicated when the decoding wheel is rotated to a specific position, there is a correlation between the rotation angle of the rotor and the corresponding number or symbol on the decoding wheel. Since the rotation of the rotor matches the rotation of the number wheel, determining (step 1116) the wheel value of the decoding wheel includes determining the value on the face of the decoding wheel based on the angular rotation or position of the number wheel, and using, for example, visual indicators (e.g., Figure 2 The indicator 224) is aligned with numbers or other symbols. For example, if the rotor's angular position is 0 degrees, the corresponding angular position of the number wheel at 0 degrees can correspond to the numerical value "zero". Similarly, if the rotor's angular position is 180 degrees, the corresponding angular position of the number wheel at 180 degrees can correspond to the numerical value "five".

[0046] Counter decoding scheme 1100 determines (step 1118) whether there are any additional rounds to be decoded. If yes (1120), the decoding round is set (step 1122) as the next round to be decoded, and execution returns to step 1106 to decode the next round.

[0047] If no additional rounds remain to be decoded (1124), counter decoding scheme 1100 can add all the decoded numbers and determine whether the resulting counter number is reasonable (step 1126). For example, if the counter number is less than the previously decoded number based on a comparison of the current number with the history log, it can be determined that the current value is unreasonable in an example where a larger number was expected. If the current number is unreasonable (1128), the execution of scheme 1100 can return to step 1104 to re-evaluate all rounds of the counter component. However, if the counter value is reasonable (1130), the counter value can be recorded (step 1132) to the history log or other memory location. Counter decoding scheme 1100 can then terminate (step 1134).

[0048] For purposes of illustration and description, the foregoing description of various preferred embodiments of the invention has been presented. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed, and many modifications and variations can be made based on the foregoing teachings. The exemplary embodiments described above were chosen and described to best explain the principles of the invention and its practical application, thereby enabling others skilled in the art to best utilize the invention in various embodiments and to make various modifications suitable for the particular intended use. The scope of the invention is intended to be defined by the appended claims.

Claims

1. An apparatus comprising: A rotary encoder, the rotary encoder comprising: A stator having an opening adapted to surround a first portion of a rotatable shaft, the stator further comprising: The emission region is located on the first concentric region of the stator; and A receiving area, the receiving area being located on a second concentric region of the stator, the second concentric region being separate from the first concentric region; A rotor having an opening adapted to surround a second portion of the rotatable shaft, the rotor further comprising: An annular conductive region, the annular conductive region being located on a first concentric region of the rotor; and At least one conductor, electrically coupled to the annular conductive region and located on a second concentric region of the rotor, the second concentric region being separate from the first concentric region; and A controller having an input coupled to the receiving region and an output coupled to the transmitting region, wherein the controller is configured to: The first signal is transmitted to the output of the controller and to the transmitting region of the stator; The second signal is received at the input of the controller and from the receiving area of ​​the stator; and Based on the second signal, the proximity of the at least one conductor to the receiving area is determined.

2. The apparatus of claim 1, wherein, The controller is configured to determine the rotational position of the rotatable shaft based on the proximity of the at least one conductor to the receiving area.

3. The apparatus of claim 2, wherein, The second signal indicates the capacitance between at least one conductor of the rotor and the receiving area of ​​the stator.

4. The apparatus of claim 1, wherein, The receiving area of ​​the stator includes a capacitive sensor array.

5. The apparatus of claim 1, wherein, The first concentric region of the stator is closer to the opening of the stator than the second concentric region of the stator.

6. The apparatus of claim 5, wherein, The stator further includes a grounding region located on a third concentric region, which is positioned between the first concentric region and the second concentric region of the stator.

7. The apparatus of claim 5, wherein, The first concentric region of the stator is configured to overlap with the first concentric region of the rotor; and The second concentric region of the stator is configured to overlap with the second concentric region of the rotor.

8. The apparatus of claim 1, wherein, At least one conductor of the rotor includes: The first conductor; and The second conductor is angularly offset from the first conductor about the axis of rotation of the rotor.

9. The apparatus of claim 8, wherein, The receiving area of ​​the stator further includes a plurality of receiving conductors, each of which is independently coupled to the controller and is angularly offset from each other about a central concentric axis of the stator; and Wherein, when the first conductor is positioned adjacent to the first receiving conductor among the plurality of receiving conductors and the second conductor is positioned adjacent to the second receiving conductor among the plurality of receiving conductors, at least the third receiving conductor among the plurality of receiving conductors is positioned between the first receiving conductor and the second receiving conductor along the shortest angular distance between the first receiving conductor and the second receiving conductor.

10. An apparatus comprising: Rotatable shaft; A rotor, the rotor being coupled to a first portion of the rotatable shaft, and comprising: A central region, the central region being located on a first concentric region of the rotor; and At least one blade, the at least one blade being coupled to and extending from the central region, the at least one blade being located on a second concentric region of the rotor; A fixing substrate, positioned adjacent to the rotor and having an opening around the rotatable axis, the fixing substrate comprising: A transmitting region, the transmitting region being configured to be capacitively coupled to the central region; and A capacitive sensor array, the capacitive sensor array being configured to be capacitively coupled to the at least one blade; and A controller, electrically coupled to the transmitting region and the capacitive sensor array, is configured to: The output of the capacitive sensor array is received based on the signal transmitted to the transmission area; and The angular rotation of the rotor is determined based on the output.

11. The apparatus of claim 10, wherein, The rotor's substrate includes printed circuit board material; and The capacitive sensor array includes copper formed on the surface of the printed circuit board material.

12. The apparatus of claim 10, wherein, The capacitive sensor array includes a plurality of receiving conductors arranged around a first concentric region of the fixed substrate; and The emission region is arranged around the second concentric region of the fixed substrate.

13. The apparatus of claim 12, wherein, When the controller is configured to determine the angular rotation, it is configured to: Determine the capacitance value between each of the plurality of receiving conductors and the rotor; Associate at least one of the plurality of receiving conductors with the at least one blade based on the determined capacitance value; as well as The angular rotation of the rotor is determined based on the angular position of the at least one receiving conductor and the angular position of the at least one blade.

14. The apparatus of claim 13, wherein, The controller is further configured to: Obtain calibration parameters for the at least one receiving conductor from a set of calibration parameters; and Determine the difference between the calibration parameters and the output of the capacitive sensor.

15. The apparatus of claim 12, further comprising: A digital wheel, which is coupled to the rotor; as well as A flow meter configured to allow an amount of either fluid or energy to flow through it, and to rotate a digital wheel based on the amount flowing through the flow meter.

16. The apparatus of claim 15, wherein, The flow meter further includes an indicator aligned with the digital wheel; and Wherein, when the controller is configured to determine the angular rotation, it is configured to: Determine the capacitance value between each of the plurality of receiving conductors and the rotor; Associate at least one of the plurality of receiving conductors with the at least one blade based on the determined capacitance value; The angular rotation of the rotor is determined based on the angular position of the at least one receiving conductor and the angular position of the at least one blade; and The angular rotation of the rotor is associated with the value of a digital wheel aligned with the indicator.

17. A controller configured to: A first signal is transmitted to a transmitting region of the stator, wherein the transmitting region is located on a first concentric region of the stator; A second signal is received from the receiving area of ​​the stator, wherein: The receiving area is located on the second concentric region of the stator; The second signal is based on the interaction between the first signal and a conductor member formed on a rotor positioned adjacent to the stator; and The conductor component includes at least one conductor blade; as well as Based on the second signal, the proximity of the at least one conductor blade to the receiving area is determined.

18. The controller of claim 17, wherein, When the controller is configured to determine the proximity of the at least one conductor blade to the receiving area, it is configured to determine the capacitance between the at least one conductor blade and the receiving area.

19. The controller of claim 18, wherein, The receiving area includes a plurality of receiving conductors arranged around the first concentric region; and Wherein, when the controller is configured to determine the capacitance between the at least one conductor blade and the receiving region, it is configured to: Determine the capacitance value between each of the plurality of receiving conductors and the conductor member; and Based on the determined capacitance value, at least one of the plurality of receiving conductors is associated with the at least one blade.

20. The controller of claim 19, wherein, The controller is further configured to determine the angular rotation of the rotor based on the angular position of the at least one associated receiving conductor.

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