Patent Description:
The present disclosure relates generally to sensor assemblies, and more particularly to wireless sensor assemblies.

Sensors such as disclosed in <CIT> and in <CIT> are used in a wide variety of operational environments to monitor operating and environmental characteristics. These sensors can include temperature, pressure, velocity, position, motion, current, voltage, and impedance sensors, by way of example. The sensors are placed in operational environment being monitored and are designed to generate an electrical signal or have a change in the electrical characteristics in response to a change in the monitored operating or environment characteristic. The change in the electrical characteristics in the sensors may be a change in impedance, voltage or current.

A sensor typically includes a probe and a processing unit. The probe acquires data from the environment and transmits the data to the processing unit, which, in turn, determines the measurements and provides a reading to a user. The processing unit generally requires a significant amount of power from a power source during data processing. The power source may be an integrated battery or may be an external power source connected to the sensor by wires. The sensor cannot be made small with the integrated battery and the processing unit. When the sensor is connected to an external power source by wires, it is difficult to use the sensor in harsh environment or to properly mount the sensor to an apparatus with complicated structure.

Although some known processing units include low-power microprocessors, these microprocessors consume a high amount of power during start-up. In some applications where energy harvesting is important, the initial amount of power consumed at start-up by the low-power microprocessors can drain an excessive amount of energy and cause a start-up failure.

These issues with power consumption and harvesting, among other issues with the operation of electronic sensors, is addressed by the present disclosure.

Referring to <FIG>, a wireless sensor assembly <NUM> constructed in accordance with a first form of the present disclosure generally includes a housing <NUM> and a sensor <NUM>. The sensor <NUM> may be inserted into an aperture (not shown in <FIG>) and connected to electrical and electronic components inside the housing <NUM>. Alternatively, a wireless sensor assembly <NUM>' according to a variant of the first form may include a housing <NUM>', a sensor <NUM>', and wires <NUM>' that connect the sensor <NUM>' to the electrical and electronic components inside the housing <NUM>'. The housing <NUM>' may further include a pair of tabs <NUM>' for mounting the housing <NUM>' to an adjacent mounting structure (not shown). The sensor <NUM> or <NUM>' may be a temperature sensor, a pressure sensor, a gas sensor, and an optical sensor, by way of example.

Referring to <FIG>, exemplary electronic components inside the housing <NUM>/<NUM>', among other components, are shown in schematic form. The electronics <NUM> generally include a wireless communications component <NUM>, which in this form is shown as a Bluetooth® RF Transmitter, and firmware <NUM> configured to manage a rate of data transmittal from the wireless communications component <NUM> to an external device (not shown). The firmware <NUM> resides in the microprocessor in this form. As further shown, a wireless power source <NUM> provides power to the electronics <NUM>. The power source <NUM> may take on any number of forms, including a battery as described in greater detail below. In this form, the power source <NUM> includes an "energy harvesting" configuration, which includes a vibrational or thermal power generator (described in greater detail below), a power conditioner, and a storage component to store excess energy.

The firmware <NUM> may also be configured to manage power consumed at initial start-up of the microprocessor. Low-power microprocessors typically consume an initial large burst of power on the order of <NUM> second or less during startup before entering true low-power mode. In an energy harvesting application dependent on a low-power mode of the microprocessor to function properly, the initial startup power burst may prove insurmountable, draining the stored energy before the initial power burst is over, causing startup failure. To address this issue of an initial start-up surge, the firmware <NUM> may be modified to spread out the initial energy burst over time such that an average power consumption is within the capability of the energy harvesting configuration. Although this spreading out of energy over time will delay start-up of the microprocessor, the stored energy will not be drained, thus inhibiting a startup failure.

In another form, additional circuitry may be added to the microprocessor to delay the output logic signal from asserting until there is enough stored energy on the storage device such that the energy harvesting components/module can get through the initial power surge. This may take the form of an external delay element or be a part of the microprocessor with a power conditioning chip. In one form, when there is ample vibrational or thermal energy available, start-up can begin without spreading burst of energy, whereas with little vibrational or thermal energy present, the energy bursts can be spread over time. In other words, the electronics may be configured to delay an output logic signal from asserting until there is sufficient stored energy to sustain an initial power surge. These and other data management functions within the processor and firmware <NUM> are described in greater detail below.

Referring to <FIG>, the housing <NUM> has opposing first and second ends <NUM> and <NUM>, defining a first aperture <NUM> (shown in <FIG>) and a second aperture <NUM>, respectively. The sensor <NUM> has a longitudinal end inserted into the first aperture <NUM> and connected to the electrical and electronic components mounted within the housing <NUM>. A communication connector <NUM> is disposed in the second aperture <NUM> and is configured to receive a mating communication connector (not shown). The second aperture <NUM> and the communication connector <NUM> may be configured differently depending on the type of the mating communication connector to be connected. For example, the communication connector <NUM> may be configured to form a Universal Serial Bus (USB) port (<FIG>), a USB-C port, an Ethernet port (<FIG>), a Controller Area Network (CAN) bus port (<FIG>) and Aspirated TIP/Ethernet port, among others. The outer profile of the housing <NUM> may be configured accordingly to accommodate the shape of the communication connector <NUM>. The mating communication connector is optional and may be used to transmit raw sensing data acquired by the sensor <NUM>, through a network, to an external or remote device (not shown) for further processing. Alternatively, the raw sensing data acquired by the sensor <NUM> may be transmitted to the external device or remote device wirelessly, which will be described in more detail below.

As further shown in <FIG>, the housing <NUM> includes an upper portion <NUM> and a lower portion <NUM>, each of the portions defining mating wedges that accommodate internal components and external features at opposing ends <NUM>, <NUM>. The lower portion <NUM> of the housing <NUM> may define the first aperture <NUM>, whereas the upper portion <NUM> of the housing <NUM> may define the second aperture <NUM>, or vice versa. The mating wedges of the upper portion <NUM> and the lower portion <NUM> define a sealing interface <NUM> along opposed lateral sidewalls <NUM>. The sealing interface <NUM> between the upper and lower portions <NUM>, <NUM> is angled so that the first aperture <NUM> is defined solely by the lower portion <NUM> (or alternatively by the upper portion <NUM>), rather than jointly by the upper and lower portions <NUM>, <NUM>. As such, sealing of the sensor <NUM> to the housing <NUM> can be made relatively easy since the sensor <NUM> is sealed to only the lower portion <NUM>, as opposed to multiple pieces (i.e., both the upper portion <NUM> and the lower portion <NUM>).

Referring to <FIG> and <FIG>, the wireless sensor assembly <NUM> further includes a mounting assembly <NUM> for mounting the sensor <NUM> to the housing <NUM>. The mounting assembly <NUM> includes a boss <NUM>, a compression seal <NUM> at a free end of the boss <NUM>, and a nut <NUM>. The sensor <NUM> is inserted through the boss <NUM>, the compression seal <NUM> and the nut <NUM>. By securing the nut <NUM> around the boss <NUM> and the compression seal <NUM>, the sensor <NUM> is secured and sealed to the housing <NUM>. The nut <NUM> may be secured to the boss <NUM> via threaded connection, press-fit connection or push-on connection. The boss <NUM> may be a separate component that is inserted into the first aperture <NUM> or may be formed as an integral part of the lower portion <NUM> of the housing <NUM>.

Referring to <FIG>, the wireless sensor assembly <NUM> further includes an anti-rotation mechanism <NUM> disposed inside the housing <NUM>, particularly in the lower portion <NUM> to prevent the sensor <NUM> from rotating when the sensor <NUM> is subjected to vibration. The anti-rotation mechanism <NUM> includes a U-shaped seat <NUM> protruding from an interior surface of the lower portion <NUM>, and an anti-rotation nut <NUM> disposed in the seat <NUM>.

The wireless sensor assembly <NUM> further includes securing features <NUM> for securing the lower portion <NUM> to the upper portion <NUM>. The securing features <NUM> may be screws and holes as shown in <FIG>. Alternatively, the upper and lower portions <NUM> and <NUM> may be secured by vibration welding, snap-fit, or any other joining methods known in the art. The upper and lower portions <NUM> and <NUM> may also include alignment features for aligning the upper and lower portions <NUM> and <NUM> during assembly.

Referring to <FIG>, the lower portion <NUM> may further include a recess <NUM> defined in a bottom surface and a magnet <NUM> received in the recess <NUM>. The external magnet <NUM> is operable for communication with the electrical and electronic components inside the housing <NUM> to disable and enable the sensor <NUM>. The magnet <NUM> may be used to open a reed switch disposed inside the housing <NUM> during shipping to disable the sensor <NUM> and preserve battery life if a battery is provided inside the housing <NUM>. During shipment, a small piece of adhesive tape may be placed over the magnet <NUM>. To make the sensor <NUM> operable, the adhesive tape and the magnet <NUM> may be removed to allow for power supply from the battery to the sensor <NUM>. The electrical and electronic components may include a latching circuitry to prevent the sensor <NUM> from be disabled if it were to encounter a strong magnetic field again. In addition, the recessed area around the recess <NUM> may serve as a "light pipe" for an indicator LED that can be used to show the functional status of the sensor <NUM>. The plastic housing material in this area may be made thinner than other parts of the housing <NUM> to allow the indicator LED to be seen through the plastic housing material.

Referring to <FIG> and <FIG>, the wireless sensor assembly <NUM> includes electrical and electronic components disposed in an interior space defined by the housing <NUM> and connected to the sensor <NUM> and the communication connector <NUM> (shown in <FIG>). The electrical and electronic components may include a communication board <NUM>, a wireless power source <NUM>, a wireless communications component, firmware (not shown), and a sensor connector <NUM> for connecting the sensor <NUM> to the communication board <NUM>. The communication board <NUM> is a printed circuit board. The wireless power source <NUM>, the wireless communications component, and the firmware are mounted on the communication board <NUM>.

Signals from the sensor <NUM> are transmitted to the communication board <NUM> via the sensor connector <NUM>. As clearly shown in <FIG>, the wires <NUM> of the sensor <NUM> are directly connected to the sensor connector <NUM>, which is mounted on the communication board <NUM>. The wireless communications component on the communications board <NUM> sends data to the external device (i.e., an external processing device) for data processing. The external device performs functions of data logging, computations, or re-transmitting the data to another remote device for further processing. The sensor <NUM> only collects raw data and transmits the raw data to the external or remote device before going to sleep. All sensing calculations, calibration adjustments, error checking, etc., are performed on the external or remote device so as not to use up any stored energy in the wireless power source <NUM> disposed within the housing <NUM>. As such, the battery life can be conserved.

The electrical and electronic components within the housing <NUM> are configured to receive power from the wireless power source <NUM> and to be in electrical communication with the sensor <NUM>. The wireless communications component has a power consumption less than about <NUM> mW. The electrical and electronic components disposed within the housing <NUM> are powered exclusively by the wireless power source <NUM>. The wireless power source <NUM> may be a battery or a self-powering device, among others. The self-powering device may be a thermoelectric device or a vibration device comprising a piezo-electric device mounted to a cantilevered board.

In one form, the wireless sensor assembly <NUM> defines a volume less than about <NUM><NUM>. The wireless communications component is configured to transmit raw data from the external sensor <NUM> to an external or remote device, such as a tablet, a smartphone, a personal computer, a cloud computer center, or any processing device that can process the data transmitted from the wireless communications component. The wireless communications component is selected from the group consisting of a Bluetooth module, a WiFi module, and a LiFi module. The firmware is configured to manage a rate of data transmitted from the wireless communications component to the external or remote device. The firmware controls a rate of data transmitted from the wireless communications component as a function of battery life. The firmware also controls a processor clock to conserve power for the wireless power source. The firmware further monitors stored energy in the wireless power source <NUM> and adjusts a rate of data transmission from the wireless communications component as a function of an amount of stored energy. This may be analogous to a low power mode in order to preserve stored energy. As such, the battery life may be conserved and besides, the sensor <NUM> may be prevented from being turned off due to loss of power or at least being delayed. The rate of data transmission may return to a predetermined normal rate until more thermal or vibration energy is available to recharge the wireless power source <NUM>.

Referring to <FIG>, a wireless sensor assembly <NUM> in accordance with a second form of the present disclosure has a structure similar to that of the wireless sensor assembly <NUM> of the first form except for the structure of the housing and the sensor. Like components will be indicated by like reference numerals and the detailed description thereof is omitted herein for clarity.

More specifically, the wireless sensor assembly <NUM> includes a housing <NUM> and a sensor <NUM> (shown in <FIG>). The housing <NUM> includes an upper portion <NUM> and a lower portion <NUM>. The lower portion <NUM> includes a pair of tabs <NUM> for mounting the housing <NUM> to an adjacent mounting structure. The sensor <NUM> is a board mount sensor. The electrical and electronic components received inside the housing <NUM> include a communication board <NUM> and a daughter board <NUM> mounted on the communication board <NUM>. The board mount sensor <NUM> is also mounted on the daughter board <NUM>. The daughter board <NUM> extends through the first aperture <NUM>, with one end extending outside the housing <NUM> and another end extending inside the housing <NUM>. Signals from the sensor <NUM> are transmitted to the communication board <NUM> via a daughter board <NUM>. The daughter board <NUM> is supported by a pair of rubber gaskets <NUM>. The pair of gaskets <NUM> also provide a compression seal between the daughter board <NUM> and the lower portion <NUM> of the housing <NUM>.

Referring to <FIG>, a wireless sensor assembly <NUM> constructed in accordance with a third form of the present disclosure generally includes a housing <NUM> having a structure similar to that of the housing <NUM> of the first form, except that no second aperture is defined in the housing <NUM> to receive a communication connector to form a communication port. Like the wireless sensor assemblies <NUM> and <NUM> of the first and second forms, the wireless sensor assembly <NUM> includes similar electrical and electronics components for wireless communications with an external or remote device and for transmitting the raw data from the sensor <NUM>, <NUM> to the external or remote device. As such, no communication port is necessary.

Referring to <FIG> and <FIG>, a wireless sensor assembly <NUM> in accordance with a fourth form of the present disclosure includes a housing <NUM> and a sensor <NUM> having a pair of wires <NUM>. The housing <NUM> includes a top housing portion <NUM>, a heat sink structure <NUM>, and a lower base <NUM>. The top housing portion <NUM> has a structure similar to the lower portion <NUM> of the first form, but is attached to the heat sink structure <NUM> in an inverted fashion. An insulation layer <NUM> is disposed between the heat sink structure <NUM> and the lower base <NUM>. The lower base <NUM> defines a pair of tabs <NUM> for mounting the housing <NUM> to an adjacent mounting structure.

In this form, the wireless sensor assembly <NUM> does not include a battery. Instead, the electrical and electronic components inside the housing <NUM> and the sensor <NUM> outside the housing <NUM> are self-powered, for example, by a thermoelectric generator (TEG) <NUM>, which is disposed within the housing <NUM>. The TEG <NUM>, also called a Seebeck generator, is a solid state device that converts heat (temperature differences) directly into electrical energy through a phenomenon called the Seebeck effect. The TEG <NUM> includes a first metallic plate <NUM> adjacent to the heat sink structure <NUM> and disposed above the insulation layer <NUM>, and a second metallic plate <NUM> disposed below the insulation layer <NUM>. The insulation layer <NUM> separates the first and second metallic plates <NUM> and <NUM>. Part of the heat generated from the electrical and electronics are conducted to the first metallic plate <NUM> and is dissipated away by the heat sink structure <NUM>. Another part of the heat generated by the electrical and electronic components inside the housing <NUM> is conducted to the second metallic plate <NUM>. A temperature difference occurs between the first and second metallic plates <NUM> and <NUM>, thereby generating electricity to power the electrical and electronic components inside the housing <NUM> and the sensor <NUM> outside the housing <NUM>.

Referring to <FIG>, a wireless sensor assembly <NUM> constructed in accordance with a fifth form of the present disclosure has a structure similar to that of the fourth form, differing only in the self-powering device. In this form, the self-powering device is a piezoelectric generator (PEG) <NUM>, which converts mechanical strain into electric current or voltage to power the electrical and electronic components inside the housing and the sensor <NUM> outside the housing. The strain can come from many different sources, such as human motion, low-frequency seismic vibrations, and acoustic noises. In the present form, the PEG <NUM> includes a power transfer printed circuit board (PCB) <NUM>, a metallic plate <NUM>, and a weight <NUM> attached to an end of the metallic plate <NUM>. The metallic plate <NUM> functions as a cantilevered board with the weight <NUM> disposed at the end to cause mechanical strain in the metallic plate <NUM>. The mechanical strain generated in the metallic plate <NUM> is converted into power/electricity, which is routed to the communications board (not shown in <FIG>) via the power transfer PCB <NUM>. The power transfer PCB <NUM> is clamped between the heat sink structure <NUM> and the metallic plate <NUM>. Like the housing <NUM> in the fourth form, the housing <NUM> of the present form includes a top housing portion <NUM>, a heat sink structure <NUM>, and a lower base <NUM>. The heat sink structure <NUM> in this form, however, only functions as a mounting structure for the sensor <NUM> and the PEG <NUM> because heat has no effect in generating electricity. Therefore, no insulation layer is provided between the heat sink structure <NUM> and the lower base <NUM>.

The weight <NUM> that is attached to the metallic plate <NUM> for causing mechanical strain in the metallic plate <NUM> may be varied and properly selected to create a resonance in the PEG <NUM> at calculated frequencies to increase the vibration and the mechanical strain in the metallic plate <NUM>, thereby increasing the electricity being generated therefrom.

Referring to <FIG>, a wireless sensor assembly <NUM> constructed in accordance with a sixth form of the present disclosure may include a housing <NUM> and a sensor (not shown) that is connected to the electrical and electronic components inside the housing <NUM> by wires <NUM>. The housing <NUM> has a rectangular configuration. The wireless sensor assembly <NUM> further includes a sensor connector <NUM> disposed at an end of the housing <NUM>, and a cap <NUM> disposed at another end of the housing <NUM>. As in wireless sensor assembly <NUM> of the sixth form, the wireless sensor assembly <NUM> includes electrical and electronic components disposed inside the housing <NUM>. The electrical and electronic components may include a communication board <NUM>, a self-powering device in the form of a piezoelectric generator (PEG) <NUM>. The PEG <NUM> may include a metallic plate <NUM>, and a weight <NUM> attached to an end of the metallic plate <NUM>. The metallic plate <NUM> functions as a cantilevered board with the weight <NUM> disposed at the end to cause mechanical strain in the metallic plate <NUM>. The mechanical strain generated in the metallic plate <NUM> is converted into power/electricity, which is routed to the communications board <NUM> to power the sensor and other electrical/electronic components.

In any of the forms described herein, the raw sensing data acquired by the sensors <NUM> can be transmitted to an external computing device, such as a laptop, smartphone or tablet, so that processing of the raw sensing data can occur externally. The wireless sensor assemblies have the advantages of reducing power consumption since raw sensing data are processed externally. In addition, since the processing and calculations of the data are performed on an external or remote device, a more complete high-resolution look-up table may be used on the external or remote device to increase accuracy, as opposed to a less accurate polynomial curve fitting that is stored in a smaller ROM due to limited space available for the ROM in the sensor.

Further, the wireless sensor assemblies have the advantages of allowing for update on the calibration curves and the look-up tables without the need to change the circuitry of the sensors. Field replacement sensors are assigned with identification (ID) information or code, such as an RFID tag or a barcode. During installation or replacement of the wireless sensor assembly, calibration information of the external sensor <NUM> can be accessed through an external device in wireless communication with the wireless sensor assembly. By scanning or entering the ID information, the sensor <NUM> will be linked to a predetermined calibration curve via a network connection. In addition, the look-up table or calibration information can be periodically updated to account for drifts, thereby increasing measurement accuracy of the sensor <NUM> over the life of the sensor <NUM>.

In one form of the wireless sensor assemblies as disclosed herein, the dimensions of the housing are approximately <NUM> in. L x <NUM> in. When a battery is used, the housing may be larger. Due to the low power consumption of the Bluetooth component as the wireless component, which is less than <NUM>. 170µW in one form of the present disclosure, the sensor <NUM> can be operated for at least <NUM> years with a selected battery while transmitting data every second. The low power consumption also makes self-powering possible. Moreover, in any of the wireless sensor assemblies described herein, the communications board can detect the amount of stored or generated energy and allow the sensor to automatically adjust the rate of transmitting the raw sensing data based on the amount of power available or predicted to be available.

The wireless sensor assembly according to any of the forms may be a digital sensing product that can transmit digital raw data to an external device or a remote device. The wireless sensor assembly includes interchangeable pieces to allow for easy assembly into multiple configurations, thus providing a "modular" construction. Each of the wireless sensor assemblies described herein can be varied to provide wired or wireless connectivity, and varied mounting and sensor input options.

While the wireless sensor assembly in any of the forms has been described to include only one sensor <NUM>, more than one sensors may be connected to the electrical and electronics components inside the housing without departing from the scope of the present disclosure. For example, two or more sensors <NUM> may be inserted into the first aperture <NUM> and mounted by the mounting assembly <NUM> as shown in <FIG> and connected to the communication board <NUM> by two sensor connectors <NUM>.

A low-power wireless sensor system constructed in accordance with a seventh form of the present disclosure may include a plurality of wireless sensor assemblies, and a wireless network operatively connecting each of the wireless sensor assemblies and operable to transmit and receive data between each of the wireless sensor assemblies. The wireless sensor assemblies may be in the form of any of the wireless sensor assemblies described in the first to sixth forms and may communicate among themselves or with an external device, such as a tablet, a smartphone or a personal computer.

Claim 1:
A sensor assembly (<NUM>) comprising a housing (<NUM>), a power source (<NUM>) configured to store and output electrical power, electronics (<NUM>), and a sensor (<NUM>), wherein
the housing (<NUM>) defines an interior space;
the sensor (<NUM>) is secured to the housing;
the power source (<NUM>) is disposed within the interior space; and
the electronics (<NUM>) are disposed within the interior space and configured to receive power from the power source, wherein the electronics (<NUM>) comprise:
a wireless communication component configured to establish a wireless communication link with an external device; and
a microprocessor configured to communicate with the external device via the wireless communication link and to execute a firmware (<NUM>), wherein the firmware is configured to :
manage a rate of data transmittal from the wireless communication component to the external device; and
spread out an initial energy burst over time to change power consumed at initial start-up of the microprocessor.