Sensor assembly for determining physical characteristics of a vehicle

Abstract

A sensor assembly for providing a physical property of a vehicle, for example the tire pressure of an aircraft wheel, comprises an electronic circuit and an exhaustible power source, such as a battery, the electronic circuit comprising a locking device (236) and a sensor suitable for sensing the physical property. In order to extend the shelf life, a first switch device (76, 232, 230, 220) and a second switch device (242, 244, 220) are functionally arranged between the power source and the circuit. The second switch device (242, 244, 220) is controlled by the locking device (236), while the first switch device (76, 232, 230, 220) can be controlled from outside the sensor assembly, for example by a magnetic field. The first switch device is arranged to switch the power source to the electronic circuit, whereby the locking device is also powered. Therefore, the locking device is able to close the second switch device (242, 244, 220). Thereafter, further stimulation of the first switch will no longer be able to close the sensor unless the locking device closes the sensor again by opening the second switch device (242, 244, 220).

Description

Technical Field

[0001] The present invention relates to a sensor assembly for determining physical properties of a vehicle, preferably an aircraft. Background Art

[0002] Conventionally, measuring parameters on an aircraft, such as tire pressure, is performed by some equipment fitted to the aircraft. These equipment are either permanently fitted to the aircraft (such as the pressure sensor of the tire pressure measurement system [TPMS]) or temporarily fitted to the aircraft during the measurement (such as the pressure gauge for tire pressure checking). All parameters used in the process are either preset constants or measured values ​​from devices permanently or temporarily present on the aircraft.

[0003] Some existing products have used devices external to the aircraft to measure vehicle parameters. An example is described in patent WO-A-2013 / 090008. However, these products use a customized, reference-specific kit (usually referred to as a "handheld device"). The device is an integral part of the product. It is provided by the product manufacturer. The product cannot be used without the device, and the device has no other purpose than for the product. This additional component is a burden for the user. It may be lost or damaged, thereby hindering the use of the entire product.

[0004] Known aircraft tire pressure measurement systems include a pressure sensor device (PSD) mounted on a dedicated port on the wheel (a "pressure port" distinct from an "inflation port") or mounted on an "inflation port" (i.e., an inflation valve) thereby preventing the tire from being re-inflated (the device must be removed in order to connect an inflation device).

[0005] In the aerospace industry, devices may be stored for several years before being installed on an aircraft. It is critical to minimize the power consumption of the PSD during storage in order to ensure that the PSD will maintain its contracted service life once installed on the aircraft.

[0006] In the prior art, powering a battery-powered device requires specific equipment and conditions. For example, in patent EP 2 465 712 A1 or US 2017 / 0250633 A1, the device is activated when subjected to a certain pressure or by receiving an activation signal.

[0007] Activation by pressure is limited because checking the correct function of the device requires applying pressure to it, which is not conducive to product control (i.e. rapid inspection of the device upon delivery). Furthermore, it means that a specific stimulus is required to activate the device, whereas in the present invention, there is no stimulus to activate the device. This makes the present invention more robust and stable.

[0008] Enabling by receiving an enabling signal requires specific equipment, which is undesirable because the specific equipment may not be available. Summary of the invention

[0009] The object of the present invention is therefore to provide a sensor for a physical property of a vehicle, in particular a sensor for the tire pressure of an aircraft, wherein the power supply of the sensor can be safely and easily switched on in order to at least increase the shelf life.

[0010] Other objectives of the preferred embodiment are:

[0011] Comply with aircraft safety requirements in terms of turning on sensors.

[0012] The first object is achieved by a sensor according to the present application. The present application proposes preferred embodiments of a sensor and a method using the sensor.

[0013] Therefore, the sensor is equipped with a primary switch that can be operated by a magnetic field. More specifically, when the magnetic field strength is above the switching threshold, the primary switch is arranged to be open-circuited, i.e. the circuit is interrupted. In addition, the primary switch is connected in parallel to a locking circuit comprising a secondary switch, which is initially open, but will be closed at least when the primary switch has been closed and the locking condition is met. Once the primary switch is closed due to a change in the magnetic field applied to the primary switch, the locking circuit is energized. Once the locking device is enabled, the locking device may switch on the second switch depending on further conditions. Since the second switch is effectively connected in parallel with the first switch, the first switch is short-circuited. Therefore, in the case where the magnetic field rises above the switching threshold again, the switched-on state is still maintained regardless of whether the primary switch changes its state.

[0014] Most actual sensor elements cannot switch on and off a considerable load like the circuit of the sensor device. In addition, sensors in real life may have switching characteristics that are opposite or different from the desired characteristics. Therefore, according to a preferred aspect, the primary switch and the secondary switch can be understood to include the actual sensor / input element and other components for switching higher power (most importantly: current) and reversing and / or improving the switching characteristics. Therefore, in a preferred variant, the power part of the primary switch and the secondary switch, such as the switching device that actually connects and disconnects the power supply to the circuit of the sensor device, can be a common part of the primary switch and the secondary switch. In other words, according to this variant, the primary switch and the secondary switch respectively include a control part and a power part, which power part (such as a power transistor) is common to both switches, and the two control parts are connected to the common power part in a way that the desired overall behavior is achieved. The logical equivalent part is in an OR-link at the output of the control part, wherein the output of the OR-link is the control input of the (common) power part. The condition that the secondary switch can only inhibit disconnection but not switching on the power supply can be achieved by the fact that the control part of the secondary switch is only energized after the primary switch has been closed. In contrast, the primary switch is permanently active and connected to the power supply as required, preferably only the part of it that is actually required can respond to externally applied fields or other stimuli. In the unpowered state, the secondary switch cannot generate a logical true level for the OR-link and therefore cannot excite the power part to connect the power supply to the circuit of the sensor device.

[0015] With regard to the preferred target characteristic of the aircraft: relative tire pressure, the sensor can therefore have a sealed arrangement, ie a sensing path only for the tire pressure. The sensor is therefore very insensitive to harmful or irritating environmental influences, in particular dirt and fluids.

[0016] Preferably, the present invention relates to a wireless, battery powered device for use as a sensor on an aircraft. To accommodate the environment, the device is completely sealed once installed on the aircraft. Any openings, buttons, connectors or anything similar that pass through the housing would compromise the robustness of the device. Therefore, the device housing is free of any mechanical means to turn the power of the device on or off.

[0017] However, it is useful to turn off the device when not in use (e.g. during storage prior to installation on an aircraft) in order to increase its lifespan (the device is powered by a battery). The present invention describes a novel method of putting a device in an ultra-low power mode that is typically used for storage, does not compromise the ruggedness of the device housing, and does not require custom tools to power the device.

[0018] The present invention does not require any special equipment to enable or disable the device. This is important because the first application of the present invention is in the field of commercial aviation. Commercial aircraft may land in remote airports with little available equipment. The same applies to commercial aviation because the logistics of equipping each location with a custom device is complex and expensive.

[0019] A simple, small, light, cheap and commonly available magnet is sufficient to deactivate the device if the location and orientation are correct and reasonable. Such a magnet can be included in the packaging of the device. Furthermore, the magnet is used to deactivate the device. The absence of the magnet results in the device being enabled, so no equipment is needed at all to enable the device. This allows for convenient use even in remote locations where specific equipment cannot be obtained.

[0020] Another aspect of the use of sensors is the presence of a portable electronic device (PED) as an evaluation device, which is provided with at least the capability of wireless communication with the sensors of the vehicle, preferably also with the capability of wireless communication with a remote database or sensor via a network (e.g. the Internet), and computing capabilities so that the PED can interrogate the values ​​of the sensors and calculate the characteristics of the vehicle based on a first parameter being the value measured by the sensor and one or more second parameters obtained from another source, which can be a sensor of the vehicle, a built-in sensor of the PED, some other sensor that can communicate with the PED, a parameter measured at a remote location or a value retrieved from a remote data source, such as a database or a data provider. For example. The actual relative tire pressure can be determined based on the absolute pressure value provided by the tire pressure sensor and the local atmospheric pressure. The atmospheric pressure can be determined by a sensor integrated in the PED (or a sensor attached to the PED), a sensor provided by the aircraft or a weather service provider.

[0021] Generally, "communication", especially with a remote data providing device like a remote server, is intended to mean any information transmission, even one-way information transmission. It even includes obtaining data that needs to be further processed by the PED, like data obtained from satellites of a GNSS.

[0022] One benefit is that a PED (portable electronic device, preferably an electronic device commonly used as an everyday personal accessory, such as a smartphone) provided by the user is preferably used. The user already owns and carries the PED. Therefore, no additional kit is required. Furthermore, there are no development and manufacturing costs associated with an additional kit, thus reducing the price of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The invention will be explained in more detail by means of preferred exemplary embodiments with reference to the attached drawings:

[0024] Figure 1Here is an overview of the interfaces between the items that may participate in the invention: a portable electronic device (PED) 1 can communicate with equipment 3 fitted on board the aircraft, can use its own sensing capabilities 5 , and can acquire data on or via the Internet 7 .

[0025] Figure 2 Here is a general flow chart of the method: Figure 2 The data flow and actions that occur in the present invention are shown. It starts with a request 11 from a user (or from an automated request system). The request goes through processing 13 and data sets are generated by all request sources 15. These data 15 are processed 17 and ultimately displayed 19 to the user (and / or transmitted to an automated system).

[0026] Figure 3 is a flow chart of an embodiment using current local parameters: the user requests 11 a relative tire pressure, but the measurement system on the wheel can conveniently only measure an absolute pressure 25. To convert the absolute pressure 25 into a relative pressure, the sensing and communication capabilities of the PED 1 are used, for example by accessing a Global Navigation Satellite System (GNSS), to determine the position of the aircraft, after pre-processing the request 13. Once the position is known, the PED 1 looks up the atmospheric pressure at the position of the aircraft on the Internet 29. Based on these data, the relative tire pressure 31 is calculated and provided to the user, for example displayed 19 to the user.

[0027] Figure 4 1 is a flow chart of an embodiment involving a prediction of future conditions, i.e. where a vehicle is planning to go: The user requests 11 the relative tire pressure at the destination airport of the vehicle. The measuring system on the wheel can conveniently only measure the absolute pressure 25. In order to convert the absolute pressure 25 into a relative pressure, the user enters 41 his destination on the PED 1 after processing 13. The PED 1 looks up 43 the atmospheric pressure at the aircraft's destination on the Internet. Based on these data, the future relative tire pressure at the destination is calculated 31 and provided 19 to the user.

[0028] Figure 5 is an example scheme for determining the tire pressure of an aircraft: A pressure sensor 47 mounted on a wheel 48 measures the absolute tire pressure. In order to provide the user with a relative tire pressure, the surrounding atmospheric pressure is required. The surrounding atmospheric pressure can be measured in three different ways. Option 1 is a measurement on a pressure sensor 47 mounted on a wheel. Option 2 is a measurement on an additional sensor 50 mounted elsewhere on the aircraft. Option 3 is a measurement performed by an external, unconnected means available on the Internet 7. All measurements are transmitted wirelessly 52 to the PED 1.

[0029] Figure 6is a longitudinal section through a portion of a wheel sensor interface (WSI) 55, a pressure sensor holder (PSH) 57: the WSI 55 is shown alone without any pressure sensor device (PSD) or retaining nut fitted. Thus, the internal valve 59 is closed and the pressurized gas 60 of the tire is contained within the WSI 55. This is an airtight configuration.

[0030] Figure 7 like Figure 6 , where a pressure sensor PSD47 is installed on the valve body: Figure 7 Shown is a WSI 55 with a PSD 47. Since there is no retaining nut fitted, the inner valve 59 remains closed. This is also a gas-tight configuration.

[0031] Figure 8 like Figure 7 , where the retaining nut 61 is attached to the WSI 55: Since the retaining nut 61 is fitted, the inner valve 59 is open and the PSD 47 is subjected to the pressure of the pressurized gas 60 of the tire. The outer valve 63 is closed, so the tire pressure is contained within the WSI 55 and the PSD 47. This is an airtight configuration. The valve cap 65 is fitted on the retaining nut 61. The valve cap 65 is a protective piece to prevent the ingress of contaminants.

[0032] Fig. 9 like Figure 6 , but the WSI 55 is provided with a passage 69 for the pressurized gas 60 of the tire: the WSI 55 is shown alone without any PSD 47 or retaining nut. In this version there is only one valve 63, which corresponds to Figures 6 to 8 Because the PSD 47 is not installed, the pressurized gas 60 of the tire will leak to the atmosphere. Since the diameter of the outlet 69 is small, the gas flow is small and the tire deflates slowly. This leaves enough time to replace the PSD 47.

[0033] Fig.10 like Fig. 9 , where the PSD 47 is fitted to the WSI 55: the tire's pressurized gas 60 is contained within the WSI 55 and the PSD 47. The PSD 47 is subjected to the pressure of the tire's pressurized gas 60. With the PSD 47 in place, it is an airtight configuration even before the retaining nut 61 is attached. A protective valve cap 65 is fitted to the WSI 55.

[0034] Fig.11 An advanced solution to increase the storage time of the sensor in storage mode: A magnet 73 placed close to the magnetic switch circuit 75 generates a magnetic field that operates the reed switch 76. This causes the magnetic switch circuit 75 to be in an open circuit state. The locking circuit 77 is also in an open circuit state. Therefore, the device is turned off.

[0035] Fig.12This is the scenario when the sensor is enabled ("exit storage mode"): the device is removed from its packaging and is therefore away from the magnet 73. The reed switch 76 has changed its state. This causes the magnetic switch circuit 75 to close. Regardless of the state of the locking circuit 77, the device is turned on.

[0036] Fig.13 like Fig.11 , after activation, i.e. after permanent activation ("normal operating mode"): the device is taken out of its packaging, so that the device is away from the magnet 73. The reed switch 76 has changed its state and the magnetic switch circuit 75 has closed. The device is thus turned on. Most importantly, the software-controlled locking circuit 77 is closed by software running on the currently powered electronics 79. Thus, the device will remain in the powered state even if the magnetic switch circuit 75 changes state, for example due to a malfunction of the reed switch 76 or some magnet moving near the device.

[0037] Fig.14 It is a schematic partial spatial view of the device with the housing opened.

[0038] Fig.15 is a flow chart for transitioning between operating states of the device.

[0039] Fig.16 , Fig.17 It is a circuit diagram. DETAILED DESCRIPTION

[0040] One aspect of measuring tire pressure is to use parameters (such as local temperature, atmospheric pressure, or altitude at the current or future location) from an external source from the aircraft (such as atmospheric pressure from a local weather service accessible via the Internet, a database on a remote server accessible via the Internet, or geographic location based on a global navigation satellite system (e.g., Global Positioning System (GPS), Galileo, etc.)) that can be accessed by a portable electronic device (PED1).

[0041] One or more physical parameters 3 are measured on board the aircraft by means of some aircraft equipment or maintenance equipment. The measured values ​​are transmitted to the PED 1 (e.g. a smartphone or tablet) for processing and display. The processing involves parameters from external sources of the aircraft (e.g., atmospheric pressure measured by the PED integrated pressure sensor 5, altitude from the PED 1's Global Navigation Satellite System (GNSS), or temperature from a weather website accessed by the PED 1 via an Internet connection 7). The result is a processed parameter value.

[0042] The present invention supplements traditional measurement techniques to provide more accurate, more meaningful or more directly applicable values ​​to the user.

[0043] The invention uses the capability of the PED 1 to use parameters from sources 5, 7 which are neither permanently nor temporarily equipped to the aircraft. This includes sensors of the PED 1 itself (such as GNSS) and data available via the Internet (such as meteorological data).

[0044] The invention has its roots in the promotion of PED1 in the aircraft maintenance industry and in everyday life. This is achieved by developing and integrating wireless transmission functions that meet aircraft standards.

[0045] The object of the present invention is to simplify and improve the measurement and processing of aircraft parameters. This is made possible by the inclusion of a PED 1 in the parameter measurement and processing chain. The PED 1 is more than just a display or processing device. The PED 1 is envisaged to be connected to the Internet 7 and the PED 1 may even have embedded sensing capabilities 5 (e.g. GNSS for geolocation sensing). The Internet connection may be used to access data on the public Internet or on private databases.

[0046] The benefits of using data from sources external to the aircraft are many:

[0047] - Some parameters can be measured by sensors that are not part of the aircraft. This reduces the equipment fitted to the aircraft (making the aircraft lighter and more reliable).

[0048] - Processing can use parameters that are not conveniently accessible to a particular aircraft system (e.g., ground-based databases or specific physical parameters that cannot be conveniently measured at the system's location).

[0049] - The processing can use parameters (e.g., weather data) of a future location (e.g., a destination airport) instead of parameters of the current aircraft location. This allows predicting future conditions of aircraft parameters. Thus, the configuration of the aircraft can be optimized taking into account the various conditions that the aircraft will face during a day or several days of operation, resulting in lower maintenance costs. For example, optimized tire pressure reduces tire wear and extends the service life of the tire.

[0050] A good example of the present invention is Figure 5 An aircraft tire pressure measurement system (TPMS) is shown in FIG. A sensor 47 mounted on an aircraft wheel 48 measures the tire pressure and transmits the result wirelessly 52 to the PED 1. System users usually want to read the relative pressure of the tire (i.e. the difference between the tire pressure and the surrounding atmospheric pressure) rather than the absolute pressure (i.e. the difference between the tire pressure and the vacuum) as this is mentioned in the aircraft maintenance documentation. This means that the system must measure both the tire pressure and the surrounding atmospheric pressure. Changes in the surrounding atmospheric pressure (due to temperature and altitude) have a non-negligible effect on the relative tire pressure.

[0051] Atmospheric pressure can be measured in a number of ways:

[0052] 1. Atmospheric pressure can be measured by a sensor 47 fitted to the tire. This requires a gas inlet hole so that the sensor is connected to atmospheric pressure. Since the sensor is in a very dirty environment (water, mud, brake dust, cleaning fluid, de-icing fluid, insects, etc.), the inlet hole is likely to become blocked. There is no effective and reliable way to prevent this from happening over time. This can lead to erroneous pressure measurements and therefore jeopardize the safety of aircraft operation. This is an undesirable solution.

[0053] 2. Barometric pressure can be measured by an additional sensor 50 mounted in a less constrained area of ​​the aircraft. Like the sensor mounted on the wheel 48, the sensor 50 transmits its measurements wirelessly to the PED 1. This requires an additional sensor. An additional item means higher cost, higher weight, and lower overall reliability. This is not an ideal solution. Furthermore, this solution cannot predict the pressure differential that the tire will encounter at the aircraft's destination.

[0054] 3. Atmospheric pressure can be measured by unconnected sensors, such as those of a local weather service. This data is available on the Internet 7. The PED 1 can access this data via its Internet connection 52. This measurement requires neither any additional equipment on the aircraft nor that of the user. Atmospheric pressure is measured by sensors that already exist and operate in the environment. This data is already available and just waiting to be used. This solution is better in terms of aircraft weight, aircraft system reliability and cost. This is a good example of the advantages of the present invention.

[0055] Tire pressure measuring device

[0056] The preferred tire pressure measuring device (wireless tire pressure gauge WTPG) comprises a pressure sensor device (PSD) 47 and a pressure sensor holder (PSH) 57. The PSD 47 contains a pressure sensor 83 and some electronics 79. The PSH 57 is a mechanical interface that allows the PSH 57 to be mounted on an aircraft wheel 48.

[0057] PSH57 implements the following functions:

[0058] -Keep the PSD47 in place on the tire inflation port;

[0059] - Connecting the pressurized gas 60 of the tire to the pressure sensor;

[0060] - Provide a means for inflating / deflating the tire 48 with the PSD 47 in place;

[0061] - Allows the PSD 47 to be replaced while the tire 48 is inflated.

[0062] The combination of these four functions allows the PSD47 to be mounted on the tire inflation valve in a convenient manner.

[0063] The present invention allows a pressure measuring device to be fitted to the inflation port of an aircraft wheel 48 while providing a standard interface for inflating the tire. This allows an aircraft without a separate "pressure port" for the wheel to be equipped without affecting maintenance. It also allows the PSD 47 to be replaced without having to deflate the tire. This is necessary because the PSD 47 is a battery powered device that needs to be replaced regularly.

[0064] The PSD47 is a battery powered device which needs to reduce its power consumption to a minimum. The PSD47 must do this in service but also during storage. In the aerospace industry, equipment can be stored for years before being installed in an aircraft. Minimizing the power consumption of the PSD47 during storage is essential in order to ensure that the contracted service life of the PSD47 is guaranteed once it is installed in an aircraft.

[0065] Since the PSD 47 is subjected to a very harsh environment after being installed on the aircraft (mounted on landing gear wheels that are subjected to impact, water, mud, dust, insects, corrosive fluids, centrifugal acceleration, etc.), it is not convenient to set a switch with on / off function on the PSD external enclosure 85. The enclosure 85 must remain completely sealed. Therefore, a non-contact switch has been developed. This non-contact switch uses a reed switch 76, which opens or closes (depending on whether the reed switch is normally closed or normally open) when subjected to an appropriate magnetic field (for example, by approaching a magnet). This allows the PSD 47 to be enabled through the PSD enclosure 85 without compromising the airtightness and robustness of the enclosure 85. The novelty lies in the "lock" function when the PSD 47 is opened. In order to prevent non-real reason closure in service due to reed switch failure (caused by vibration, impact, high centrifugal acceleration, etc.), the PSD 47 can be locked in the open state by software.

[0066] Implementation method: Two valves in series

[0067] The solution comprises two valves 59, 63 in series. The inner valve 59 is located between the tire 48 and the PSD 47. The outer valve 63 is located between the PSD 47 and the inflation interface 87. The inner valve 59 allows the PSD 47 to be removed without deflating the tire 48. The outer valve 63 allows the usual inflation device to be blocked. The inner valve 59 is included in the first element of the PSH 57, which is called the wheel sensor interface (WSI) 55. The outer valve 63 is included in the second element of the PSH 57, which is called the retaining nut 61. The two valves 59, 63 comprise standard aircraft wheel valve cores. The two valves 59, 63 are normally closed (and are kept closed by springs 89, 91). The two valves 59, 63 open when the rods 93, 95 are pushed.

[0068] exist Figures 6 to 8 (and Figures 9 and 10 In the drawings (and those related to the alternative embodiments described below), the dotted areas are areas of pressurized gas 60 connected to the tire. For the interfaces between removable components such as PSD 47, even if not explicitly mentioned, conventional means for sealing to prevent pressure loss, such as O-rings 97 (see Fig.10 ).

[0069] When the WSI 55 is only fitted on the wheel 48, the internal valve 59 is closed. The pressurized gas 60 of the tire is maintained. The WSI 55 is screwed into the wheel 48 rim to replace the original inflation valve. It has the same thread.

[0070] When PSD47 slides onto WSI55 ( Figure 7 ), nothing happens. PSD47 is in place but not connected to the tire's pressurized gas 60. When the retaining nut 61 is screwed onto the WSI 55, the design features of the retaining nut 61 push on the inner valve 59 and open the inner valve 59. The tire's pressurized gas 60 flows through the inner valve 59. The outer valve 63 remains closed. If an inflation device is connected to the retaining nut 61, the outer valve 63 will open. The threads 99 on the free end of the retaining nut 61 have exactly the same interface (thread and thread length) as the original inflation valve. PSD47 rotates freely around PSH57 until the retaining nut 61 is tightened. The orientation of the PSD47 around the PSH57 does not matter. The circumferential groove 100 in the PSH57 or PSD47 (or both) allows the PSD47 to withstand the pressure of the tire's pressurized gas 60 regardless of its orientation. In this way, the PSD 47 can be secured in any rotational position on the PSH 57 while maintaining a fluid connection between the pressurized gas 60 and the PSD 47 , and in particular the pressure sensor 83 of the PSD 47 .

[0071] A standard valve cap 65 identical to one of the original inflation valves is screwed onto the threads 99 of the free end of the retaining nut 61. The valve cap 65 protects the valves 59, 63 from contamination (e.g., water, dust, etc.). Thus, the threads 99 are identical to or ultimately compatible with the threads of the original inflation valve, so that accessories such as the cap 65 can be attached to the free end of the retaining nut 61 as if they were attached to the original inflation valve.

[0072] Alternative embodiment: a single valve

[0073] Although the solution of two valves in series described previously meets all the expectations, it is rather complex and expensive to manufacture. A second variant has been designed and tested which achieves the same function with a simpler design: the internal valve is omitted and the retaining nut 61 becomes simpler. This results in a PSH57 that is cheaper, lighter, more compact and more reliable (because it contains fewer parts).

[0074] The function performed by the internal valve 1 (maintaining tire pressure during PSD 47 change) is performed by a very small sized hole 69 which directs pressure from the interior of the WSI 55 to the PSD 47. When the PSD 47 is removed, the tire gas flows freely to the atmosphere and the tire deflates. However, since the hole 69 in the WSI 55 is very small, the gas flow is also very small. Therefore, the operator has enough time to remove and reinstall the PSD 47 before tire deflation becomes a problem. The novelty lies in the combination with the external valve 63 which allows the connection of an inflation device and the inflation of the tire.

[0075] Conservative calculations show that a hole diameter of 0.25 mm to 0.5 mm achieves the desired performance. Such a hole diameter results in a tire pressure drop of only 2 pounds per square inch (PSI) (138 hPa, i.e., approximately 150 hPa) over 30 seconds. This complies with maintenance procedures and tire restrictions, and leaves the operator ample time to replace the PSD 47. More generally, values ​​of gas pressure loss of up to 2000 hPa, preferably up to 500 hPa, or more preferably up to 300 hPa within 30 seconds are acceptable.

[0076] The WSI 55 is screwed into the wheel 48 rim to replace the original inflation valve. The WSI 55 has the same threads. When the PSD 47 is slid onto the WSI 55, the PSD 47 is subjected to the pressure of the tire's pressurized gas 60 and the tire's pressurized gas no longer leaks into the atmosphere. The tire no longer deflates.

[0077] A retaining nut 61 is screwed onto the WSI 55 to secure the PSD 47 in its position. In this single valve design, the retaining nut 61 is actually a simple nut. The (external) valve 63 remains closed. If an inflation device is connected to the retaining nut 61, the valve 63 will open. The thread 99 on the free end of the PSH 57 has exactly the same interface (thread and thread length) as the original inflation valve. The general considerations for the thread 99 set forth above in the aforementioned embodiment also apply. The PSD 47 rotates freely around the PSH 57 until the retaining nut 61 is tightened. The orientation of the PSD 47 on the PSH 57 does not matter. The circumferential groove 100 in the PSH 57 or the PSD 47 or both allows the PSD 47 to withstand the pressure of the pressurized gas 60 of the tire regardless of its orientation.

[0078] A standard valve cap 65, identical to the one in the original inflation valve, is screwed onto the threads 99 of the free end of the retaining nut 61. The valve cap 65 protects the valve 63 from contamination (e.g. water, dust, etc.).

[0079] Common features of valve arrangements

[0080] Both designs (two valves in series or a single valve) perform four main functions:

[0081] - Hold the PSD 47 in place on the tire inflation port;

[0082] -Connect the tire air pressure to the pressure sensor;

[0083] - Provide a means to inflate / deflate the tire with the PSD 47 in place;

[0084] - Allows PSD47 to be replaced while the tire is inflated.

[0085] (Ultra) Low Power Storage Mode for Tire Pressure Measurement Devices

[0086] The means for placing the PSD 47 in a low power mode is based on a magnetic switch circuit 75 which includes a reed switch 76 and a lock circuit 77 for locking the entire circuit in a powered state.

[0087] The purpose of the magnetic switch circuit 75 is to change state when a magnetic field is applied or removed in order to shut down the device and increase the life of the battery 103. The presence of a magnetic field can only be ensured during storage (controlled environment) and not during operation, so the storage mode occurs when the magnetic field is applied. Therefore, the normal operating mode occurs when the magnetic field is removed.

[0088] The magnetic switch can be one of the following:

[0089] - A normally closed reed switch that opens when a magnetic field is applied.

[0090] - A normally open reed switch that closes when a magnetic field is applied and is integrated into a magnetic switch circuit 75 that reverses the effect (i.e., the effect of an open circuit when a magnetic field is applied). This solution may be preferred because a normally open reed switch may be more reliable than a normally closed reed switch.

[0091] The most convenient way to apply a magnetic field is with a magnet 73. The magnet 73 is included in the device shipping package and is in a precise position and orientation to keep the device in storage mode. Once the device is removed from its packaging, the device automatically opens. If the device is placed back into its packaging, the device will close.

[0092] The reed switch 76 is located just below the device housing 105 so that the magnetic field generated by the magnet 73 located near the device operates the reed switch 76. The housing is transparent to the magnetic field, or at least sufficiently permeable to the magnetic field so that the magnetic switch can be operated by the magnet located near the housing 105.

[0093] Fig.13 The device is shown in a state where it is removed from its packaging, so that the magnet 72 is removed. The magnetic switch circuit 75 is therefore closed and the device is therefore powered on. The locking circuit 77 of the magnetic switch circuit is still open, which means that the device is not locked in the operating mode. If the device encounters an undesirable magnetic field or if a mechanical failure of the reed switch 76 occurs, the device can revert back to the ultra-low power mode.

[0094] When the device is mounted on the aircraft, the device is configured by the user via an application (software) running on the PED1. Once the configuration is entered, the device knows that it is mounted on wheels 48. When the configuration is entered, the software resident in the electronics 79 of the device commands a transistor (or another switching component, such as an electronic switch). The transistor closes a lock circuit 77, which locks the device in the powered-on state. When the lock circuit 77 is closed, the state of the reed switch 76 (open or closed) does not matter. Even if the reed switch 76 changes state, the device remains powered-on. This feature protects the operation of the device from failure of the reed switch 76. This feature also protects the device from interference from undesirable magnetic fields that may be present in the environment.

[0095] Fig.13This locking state is illustrated: the device is in operating mode and the locking circuit 77 of the magnetic switch circuit is closed. The locking circuit 77 of the magnetic switch circuit is closed because the software in the electronic device 79 commands the electronic switch (e.g., transistor) to be closed. The software commands the electronic switch to be closed because the software has received a configuration command from the user, so the software knows that it is installed on the aircraft. Since the locking circuit 77 of the magnetic switch circuit is closed, no matter what state the magnetic switch circuit 75 is in, the device is locked in the operating mode. This makes the design robust because even if the device encounters an undesirable magnetic field or a reed switch 76 fails, the device will not exit the operating mode.

[0096] If the device configuration is deleted by the user, i.e. the software is in a state where the device is no longer installed on the aircraft, the software stops commanding the transistor and the lock circuit 77 opens. The magnetic switch circuit 75 is then no longer bypassed. This feature allows the device to be returned to storage in an ultra-low power mode after a period of operation.

[0097] The entire circuit is designed to minimize leakage current. In battery-powered devices, small amounts of leakage current can have a significant adverse effect on service life. The described embodiments minimize leakage current to a few nanoamperes (at most 100 nanoamperes, preferably at most 50 nanoamperes, 30 nanoamperes, 20 nanoamperes, 10 nanoamperes, or increasingly preferably even 5 nanoamperes).

[0098] State Flow Diagram( Fig.15 )

[0099] Fig.15 States of the device and transitions between states are shown: 201 Typically when the device is placed in its delivery packaging, the magnet is located in the immediate vicinity of the device.

[0100] 202 The magnet is removed from the immediate vicinity of the device and the device switches to state 203 .

[0101] 203 The device is in full operational mode, but may still be disturbed, for example by undesired magnetic fields, because the device is not locked in the power-on mode (lock not engaged).

[0102] 204 Magnet placed in close proximity to device: device changes back into passive mode (ultra low power mode).

[0103] 205 The device is configured by the user via wireless communication: the device enters state 206 .

[0104] 206 The device is in full operational mode and will not be affected by undesired magnetic fields or magnetic switch failures: the lock is engaged.

[0105] 207 Device configuration deleted by user via wireless communication: the device returns to state 203.

[0106] Electronic Schematics

[0107] The circuit is implemented using a simple electronic switch 220 (e.g. a transistor) which is controlled by an OR'ed command 222 of the reed switch 76 and a signal 224 from a microcontroller (software driven, not shown). "Microcontroller" means a part designed to measure a physical property or multiple physical properties (according to this embodiment, the internal pressure of the tire) and for auxiliary functions, such as sensor circuits interfacing with the PED and deriving the signal 224 from the status of the device. It is worth noting that if the sensor device has not yet been configured, the signal 224 is off or not true, and once the sensor device is configured, the signal 224 switches to on or true. The output terminal 226 of the electronic switch 220 is the power supply of the microcontroller. The input terminal 228 of the electronic switch 220 is connected to the power supply of the sensor device, in particular a battery. With Figures 11 to 13 Unlike the reed switch 76, the magnetic switch does not switch power directly, but rather connects the signal to the locking logic via an OR'd command 222 which provides a control signal to the electronic switch 220. Thus, the reed switch 76 can be optimized for sensitivity but does not need to be designed to carry large amounts of current.

[0108] The reed switch 76 has its contacts open in a standby state, i.e., in the absence of a magnetic field or when exposed to a magnetic field below its switching level (e.g., a normally open reed switch). When a magnet is present, i.e., located sufficiently close to the reed switch 76 to generate a magnetic field with a strength above the switching level of the reed switch 76 by the magnet, the reed switch 76 is held in a closed position by the magnetic field. This holds the electronic switch 220 in an open position.

[0109] When the magnet is removed (placed further away), the reed switch 76 opens, the OR'd command 222 changes the logic level at the control input of the electronic switch 220 from an open (interrupt) level to a closed level, and the electronic switch 200 thus connects the battery to the device electronics, i.e., the input 228 and the output 226.

[0110] The electronic switch 200 is also controlled by a signal 202 from a microcontroller on which runs software for controlling the sensor device, determining measured values, providing retrieved data to a receiver device, and the like.

[0111] Fig.17The electronic circuit is shown in more detail. The magnetic switch is connected to the input terminal 228 and the middle connection of the voltage divider formed by resistor 230 and resistor 232. The other terminal of resistor 230 is connected to the gate of a field effect transistor (FET transistor), which is the electronic switch 220, and the second terminal of resistor 232 is grounded. Capacitor 234 in parallel with resistor 232 suppresses the effect of contact bounce.

[0112] In low power mode, i.e., a magnet is close to the reed switch 76 and the reed switch 76 is therefore closed, the gate of the electronic switch (transistor) 220 is connected to the source of the transistor via the resistor 230. When the gate of the electronic switch (transistor) 220 is connected to the source, i.e., the gate and the source are at substantially the same voltage, the electronic switch (transistor) 220 is a type of switch that constitutes a high resistance, i.e., represents a switch in an off state.

[0113] The current through the reed switch 76 and the resistor 232 is the main cause of power consumption in the low power state. With a power supply of a certain level of volts, the resistor must be at least 1 megohm (1 megohm = 10 6 ohms), preferably at least 4 megohms, 10 megohms, 20 megohms, 4 megohms and increasingly preferably even 100 megohms.

[0114] The "microcontroller" 236 is disconnected from the power supply at input 228, so its output 238 is inactive and mostly at ground potential. The gate of transistor 242 is also connected to ground, but as usual a resistor 244 is provided to safely keep the gate at ground potential. Transistor 242 is also of the type that turns off if its gate is at the same potential as its source.

[0115] In order to minimize power consumption, especially in this switching mode, it is of utmost importance that the electronic switch (transistor) 220 is a metal oxide semiconductor field effect transistor ((MOS-)FET) and that the transistor 242 is also a metal oxide semiconductor field effect transistor. Thus, if the reed switch 76 is closed, a high resistance value can be selected for the resistor 232 through which the current flows.

[0116] Once the magnet is removed, the reed switch 76 opens and the gate 238 of the transistor is brought to the ground connector 240 through the resistor 230 and the resistor 232 while the capacitor 234 discharges, the electronic switch (transistor) 220 becomes a low resistance equivalent to closing the switch, and the microcontroller 236 is powered on. The device is now in state 203 ( Fig.15 ), i.e. active state but not configured. In particular, automatic reset is preferred, which ensures a predefined, unconfigured state after power-on.

[0117] Performing the configuration (transition 205) requires the microcontroller 236 to enable its output 236, so that a high potential is applied to the gate of the transistor 242. The transistor 242 obtains a low resistance corresponding to the state 206 and shorts the resistors 230, 232. In this state, the activation of the reed switch 76 by the magnetic field will not have any effect on the state of the electronic switch (transistor) 220, so the sensor device is locked in the on state or powered state.

[0118] The configuration can be any useful entry, starting with just inputting data, which means that the device must remain switched on. Other useful data include an indication of the state of the sensor attached to the aircraft, an indication of which wheel and which tire of the aircraft the sensor is attached to, and other data. These data can be permanently stored in a memory (not shown) included in the sensor, more specifically in a microcontroller, so that the microcontroller can access these data.

[0119] Removing these data - i.e. resetting the microcontroller 236 essentially to the configuration it had immediately after power-on - is detected by the microcontroller 236 and causes its output 238 to be inactive (transition 207). The gate of the transistor 242 is again brought to the ground connector 240, the transistor 242 becomes non-conductive, and the system returns to the state 203, in which it is no longer locked in the switched-on state. By approaching a magnet, for example by putting the sensor back in place in the package in which the magnet is provided, the sensor can be deactivated again, i.e. switched back into the (ultra) low power mode (state 201).

[0120] The main advantage of the described embodiment is that no specific equipment is required to enable or disable the device. This is important because the first field of application of the present invention is the aviation field. Aircraft and especially commercial aircraft may land in remote airports where there is little available equipment. In addition, commercial aircraft operators cannot afford to use custom equipment to generate signals to enable the pressure sensing device. Commercial aircraft fly all over the world, and it is neither practical nor economical (and environmentally friendly) to provide such custom equipment at hundreds of airports. Not requiring specific equipment to enable or disable the device is a significant improvement over the prior art. If the positioning and orientation are accurate and reasonable, a simple, small, light, cheap and commonly used magnet is sufficient to disable the device. Such a magnet can be included in the packaging of the device. In addition, the magnet is used to disable the device. The absence of the magnet can cause the device to be enabled, and no equipment is required to enable the device at all. This makes it convenient to use even in remote locations where specific equipment cannot be obtained.

[0121] From the description of the preferred embodiments, a person skilled in the art may derive a variety of variations and alternatives without departing from the scope of protection defined by the claims. It is conceivable that, for example:

[0122] Use of the present invention on other vehicles other than aircraft.

[0123] • The wireless communication range between the sensor and the PED is at least 5m, preferably at least 10m, and more preferably at least 15m, so that sensor data can be retrieved without close proximity to the sensor, which may be inconvenient or difficult due to the location where the sensor is mounted on the vehicle.

[0124] The range of the wireless communication sensor / PED may be at most 100m, preferably at most 50m

[0125] m, in order to reduce the risk of contact with other sensors, especially sensors of other vehicles.

[0126] PED is a portable device, such as a smartphone, tablet computer, laptop computer, etc., which is a common work equipment and can execute the following software: the software is the software required to perform the method according to the present invention.

[0127] • The gas used to inflate the tyre may be air or any other gas known in the art for this purpose.

[0128] • The PSD may not be provided with an integrated wireless communication unit, but may be connected to a wireless communication unit arranged elsewhere in the vehicle.

[0129] The interface between the PSD and the PSH is not circularly symmetric, but rather provides a regular polygonal interface, allowing the PSD to be mounted on the PSH in a plurality of predefined orientations. The polygon may be a triangle, square, pentagon, hexagon, etc., allowing 3, 4, 5, 6 or more rotational positions. Regular in this context means that the edges of the polygon have the same length, thereby making the edges of the polygon sequentially rotationally symmetric. It is even conceivable to use another cross section of 2nd order rotational symmetry, such as a trapezoid, an ellipse or a stadium shape (a rectangle with semicircles on opposite sides), or a cross section of higher rotational symmetry, such as 3rd, 4th, 6th, 8th order rotational symmetry.

[0130] Further qualifications on innovation are given in Appendix A.

[0131] Glossary

[0132] A / C Aircraft

[0133] FET Field Effect Transistor

[0134] GNSS Global Navigation Satellite System (Global Positioning System GPS, Glonass System, Galileo System)

[0135] GPS Global Positioning System maintained by the United States Air Force; also used as a generic name for GNSS hPa Hectopascal; 1 hPa = 100 Pa PED Portable electronic device. Preferably a device that is light and small enough to be carried by an individual as part of personal clothing.

[0136] PSD pressure sensing device

[0137] PSH Pressure Sensor Holder

[0138] TPMS tire pressure measurement system

[0139] WSI Wheel Sensor Interface

[0140] WTPG wireless tire pressure gauge, a tire pressure measurement device with wireless communication function Appendix A

[0141] Aspects of the objects and methods described

[0142] 1. A method for determining a property of a vehicle, in particular an aircraft, wherein the property is calculated as a function of at least one first parameter and at least one second parameter, wherein the first parameter is determined on the vehicle itself,

[0143] It is characterized in that

[0144] - at least one of the first parameters is determined by a first sensor (47) arranged on the vehicle, the sensor being provided with or connected to a wireless communication unit, or the sensor being provided with or connected to a wireless communication unit;

[0145] - the first sensor wirelessly transmits at least one of the first parameters to an evaluation device, the evaluation device being provided with a wireless communication unit arranged for transmitting at least one of the first parameters;

[0146] - the evaluation device (1) retrieves at least one of the second parameters; and - the evaluation device (1) calculates the characteristic using at least one of the first parameters and at least one of the second parameters.

[0147] 2. The method according to item 1, characterized in that at least one of the second parameters, preferably all of the second parameters, are retrieved from at least one of the following sources:

[0148] - a built-in second sensor (5) of the evaluation device;

[0149] - means of the vehicle arranged to communicate wirelessly with the evaluation device (1);

[0150] - Providing data from a remote device, preferably a private database or a public network, via a communication unit, preferably a wireless communication unit, of the evaluation device.

[0151] 3. A method according to one of items 1 to 2, characterized in that the evaluation device (1) is a device that can be carried by a person, preferably provided with a display device for displaying the value of the characteristic to be determined to the person, and provided with a wireless communication unit for retrieving the second parameter.

[0152] 4. A method according to one of items 1 to 3, characterized in that the second parameter is retrieved approximately simultaneously with the first parameter, in particular when the evaluation device is within the range of the wireless communication unit of the first sensor, or before or after receiving at least one value of at least one of the first parameters.

[0153] 5. A method according to one of items 1 to 4, characterized in that at least one of the second parameters is related to a position remote from the position of the vehicle, so that the characteristic is calculated when the vehicle is in a remote location.

[0154] 6. Method according to one of items 1 to 5, characterized in that the characteristic is the relative tire pressure of at least one wheel of the vehicle, at least one first parameter is the absolute pressure of the tire and at least one second parameter is the atmospheric pressure.

[0155] 7. Method according to one of items 1 to 6, characterized in that the vehicle is an aircraft, preferably an aircraft having wheels (48) provided with pneumatic tires.

[0156] 8. A method according to one of items 1 to 7, characterized in that the range of wireless communication between the first sensor (47) and the evaluation device (1) is limited to a lower limit of at least 5 m, preferably 10 m, more preferably at least 15 m, and optionally an upper limit of 100 m, preferably 50 m.

[0157] 9. A sensor assembly providing a pressure value of an inflated tire of a wheel (48), preferably a pressure value of a tire (48) of an aircraft, for use in a method according to one of items 1 to 8, characterized in that the sensor assembly comprises a gas pressure sensor unit (47), the gas pressure sensor unit (47) comprising a gas pressure sensor (83), wherein the gas pressure sensor unit is arranged to be inserted between a valve seat and a valve (63) of the wheel (48), and in addition to an optional passage for gas to the gas pressure sensor, the gas pressure sensor unit is contained in an airtight housing (85) so that the gas pressure sensor unit is protected from the ingress of substances from the environment that are liable to impair the functionality of the gas pressure sensor unit.

[0158] 10. A sensor assembly according to item 9, characterized in that the sensor assembly includes an adapter (55), which is arranged to be attached to a wheel (48) having an original valve arranged in a valve seat to replace this valve, wherein the adapter is provided with a valve (63) so that the interior of the adapter has a passage leading to the pressurized interior of the wheel, and wherein the adapter includes an interface surface, which is shaped in the following manner: the gas pressure sensor unit (47) can be attached to the adapter in an airtight manner on the interface surface.

[0159] 11. A sensor assembly according to item 10, characterized in that the adapter (55) is provided with a hole (69) in the interface surface so that pressurized gas (60) can be obtained at the interface surface, the interface surface is shaped to have a cylindrical cross-section or a cross-section with at least 2nd order rotational symmetry, preferably a regular polygonal cross-section, and at least one of the adapter and the gas pressure unit is provided with at least one of the following in the interface surface:

[0160] a circumferential groove (100) at the location of the hole, the gas pressure sensor (83) being arranged to be able to use the groove when the gas pressure sensor unit (47) is mounted on the adapter; and

[0161] - At least one of the following:

[0162] - one or more holes (69) located in the interface surface of the adapter; and

[0163] - one or more inlet openings for the gas pressure sensor, the inlet openings being located in the interface surface of the gas pressure sensor unit (47);

[0164] Make

[0165] - Via groove or

[0166] - by aligning one of said holes in said interface surface in said adapter with one of said inlet openings of said gas pressure sensor,

[0167] The gas pressure sensor unit (47) is mountable in at least three different rotational positions on the adapter while maintaining a fluid connection between the aperture in the adapter and the gas pressure sensor.

[0168] 12. A sensor assembly according to item 11, characterised in that the hole has a maximum gas permeability so that when the aircraft is mounted on the wheel of the aircraft, the volume of gas flowing through is below a predetermined limit during the prescribed maximum time required to replace the sensor unit (47), which would result in a loss of tire pressure and require maintenance of the wheel and / or tire, preferably, the pressure loss within 30 seconds is at most 2000 hPa, preferably at most 500 hPa and most preferably at most 300 hPa.

[0169] 13. A sensor assembly according to one of items 9 to 12, characterized in that the pressure sensor unit (47) is provided with a wireless communication part, preferably a standard type of wireless communication part, and more preferably a Bluetooth communication part, so that the measured gas pressure value can be transmitted to a remote device (1) within the range of the wireless communication unit.

[0170] 14. A sensor assembly according to one of items 9 to 13, characterized in that the sensor assembly comprises an electronic circuit, in particular a depletable power source (103) of a battery, and a first switching device and a second switching device, the electronic circuit comprising the gas pressure sensor, the first switching device and the second switching device being functionally arranged in parallel and located between the circuit and the power source, wherein the first switching device can be controlled from outside the gas pressure sensor unit (47), preferably by means of a field, more preferably by means of a magnetic field, and the second switching device can be controlled by the circuit so that, starting from a storage mode in which both switching devices are open, the first switch can be closed from outside the gas pressure sensor unit and the energizing circuit enables the second switching device so that reopening the first switching device does not interrupt the connection between the power source and the circuit.

[0171] 15. Sensor assembly according to item 14, characterized in that a field source, preferably a magnet, present within a minimum distance keeps the first switch unit electrically open, the first switch being designed to be electrically closed in the absence of a field.

Claims

1. A sensor assembly providing a value of a physical property of a vehicle, characterized in that The sensor assembly comprises an electronic circuit, the electronic circuit comprising a sensor suitable for sensing a physical property and a locking device, and the sensor assembly further comprises a depletable power supply (103), and a first switch device and a second switch device, the first switch device and the second switch device being functionally arranged in parallel and located between the electronic circuit and the power supply, wherein the first switch device is controllable from outside the sensor assembly and the second switch device is controllable by the locking device, so that starting from a storage mode in which both the first switch device and the second switch device are open, the first switch device can be closed from outside the sensor assembly and the locking device is energized, thereby enabling the second switch device, so that reopening the first switch device can no longer interrupt the connection between the power supply and the electronic circuit, Wherein, the first switching device and the second switching device jointly include a switching element and an "OR" logic unit having at least two input terminals and an output terminal, one input terminal is assigned to the first switching device, and the other input terminal is assigned to the second switching device, and the output terminal is functionally connected to the control input terminal of the switching element, wherein the switching element is arranged to: by closing the switching element, the power supply is connected to the electronic circuit of the sensor component.

2. The sensor assembly according to claim 1, characterized in that The first switching device comprises a field-sensitive switching element configured such that the switching element is electrically closed when a field source is present and the switching element is open when no field is present.

3. The sensor assembly according to claim 1, characterized in that The first switching device comprises a mechanical switching element, which comprises at least one movable contact member which is sensitive to a magnetic field, so that the switching element can be closed or opened by a magnetic field penetrating the mechanical switching element.

4. The sensor assembly according to claim 1, characterized in that The switching element includes a field effect transistor (220) having a gate, a source and a drain terminal.

5. The sensor assembly according to claim 1, characterized in that The powered electronic circuit is capable of switching between an unconfigured state and a configured state, wherein the locking device keeps the second switch device closed in the configured state and keeps the second switch device open in the unconfigured state, so that when the electronic circuit is in the unconfigured state, power to the electronic circuit can be interrupted by opening the first switch device.

6. The sensor assembly according to claim 5, characterized in that The sensor assembly includes a storage unit storing configuration data, and a reset unit establishing the configuration data in the unconfigured state.

7. The sensor assembly according to claim 2, characterized in that: The electronic circuit comprises a power supply voltage input terminal (226) and a ground input terminal for supplying power to the electronic circuit; The depletable power supply (103) includes a power supply voltage output terminal (228) and a ground connector (240); The switching element includes a field effect transistor having a gate as a control terminal, and a drain and a source, the field effect transistor being of a type having a high resistance, wherein the gate and the source are close to or at the same potential, and the source and the drain are connected to one of a plurality of pairs of power supply voltage terminals or ground terminals of the electronic circuit and the power supply; The first switching device comprises the following, both having a first terminal and a second terminal: the switching element, which can be switched on and off by the presence or absence of a magnetic field, a first resistor (232) and a second resistor (230), wherein the switch element, the first resistor and the second resistor are connected via the first terminal, the second terminal of the switch element is connected to the source of the field effect transistor, the second terminal of the first resistor is connected to the ground connector of the power supply, and the second terminal of the second resistor is connected to the gate of the field effect transistor; The second switch device (242) has a control terminal and two working terminals, the resistance between the two working terminals can be switched from high resistance to low resistance through the control terminal, one working terminal is connected to the gate of the field effect transistor, and the other working terminal is connected to the ground connector of the power supply; Wherein, the locking device has an output end connected to the control terminal of the second switching device.

8. The assembly according to claim 7, characterized in that The first resistor (232) has a resistance of at least 1 megohm.

9. The sensor assembly according to claim 1, characterized in that The sensor assembly comprises a gas pressure sensor unit (47), the gas pressure sensor unit (47) comprising a gas pressure sensor (83), wherein the gas pressure sensor unit is arranged to be inserted between a valve seat of a wheel (48) and a valve (63), and except for a passage for gas to pass to the gas pressure sensor, the gas pressure sensor unit is contained in a gastight housing (85) so that the gas pressure sensor unit is protected from the ingress of substances from the environment that are liable to impair the function of the gas pressure sensor unit.

10. The sensor assembly according to claim 9, characterized in that The sensor assembly comprises an adapter (55) arranged to be attached to a wheel (48) having an original valve arranged in a valve seat to replace this valve, wherein the adapter is provided with a valve (63) so that the interior of the adapter has a passage to the pressurized interior of the wheel, and wherein the adapter comprises an interface surface shaped in such a way that the gas pressure sensor unit (47) can be attached to the adapter in a gas-tight manner on the interface surface.

11. The sensor assembly according to claim 10, characterized in that The adapter (55) is provided with a hole (69) in the interface surface so that pressurized gas (60) is available at the interface surface, the interface surface is shaped with a cylindrical cross section or a cross section with rotational symmetry of at least 2 orders, and at least one of the adapter and the gas pressure unit is provided with at least one of the following in the interface surface: a circumferential groove (100) at the location of the hole, the gas pressure sensor (83) being arranged so that the gas pressure sensor can use the groove when the gas pressure sensor unit (47) is mounted on the adapter; and At least one of the following: one or more of said holes (69), said holes (69) being located in said interface surface of said adapter; and one or more access openings for the gas pressure sensor, the access openings being located in the interface surface of the gas pressure sensor unit (47); Make Through the groove or by aligning one of the holes in the interface surface in the adapter with one of the inlet openings of the gas pressure sensor, The gas pressure sensor unit (47) is mountable in at least three different rotational positions on the adapter while maintaining a fluid connection between the aperture in the adapter and the gas pressure sensor.

12. The sensor assembly according to claim 9, characterized in that The pressure sensor unit (47) is provided with a wireless communication section so that the measured gas pressure value can be transmitted to a remote device (1) within the range of the wireless communication unit.

13. Sensor assembly according to one of claims 1 to 4, characterized in that The sensor assembly provides a pressure value of a pneumatic tire of a wheel (48).

14. The sensor assembly according to claim 13, characterized in that The sensor assembly provides pressure values ​​for the tires of the wheels (48) of the aircraft.

15. Sensor assembly according to one of claims 1 to 4, characterized in that The power source (103) is a battery.

16. Sensor assembly according to one of claims 1 to 4, characterized in that The first switching device is controlled from outside the sensor assembly by means of a field.

17. The sensor assembly according to claim 16, characterized in that The first switching device is controlled from outside the sensor assembly by means of a magnetic field.

18. The sensor assembly according to claim 2, characterized in that The field source is a magnet (73).

19. The sensor assembly according to claim 3, characterized in that The switch element is a reed switch (76).

20. The sensor assembly according to claim 4, characterized in that The field effect transistor (220) is of a type having a high resistance between source and drain, wherein the gate is at the voltage level of the source.

21. The sensor assembly according to claim 7, characterized in that The switch element is a reed switch (76).

22. The sensor assembly according to claim 7, characterized in that The second switching device (242) is a transistor.

23. The sensor assembly according to claim 22, characterized in that The second switching device (242) is a field effect transistor.

24. The sensor assembly according to claim 8, characterized in that The first resistor (232) has a resistance of at least one of 4 megaohms, 10 megaohms, 20 megaohms, 40 megaohms, and 100 megaohms.

25. The sensor assembly according to claim 11, characterized in that The interface surface is shaped to have a regular polygonal cross-section.

26. The sensor assembly according to claim 12, characterized in that The wireless communication part is a standard type of wireless communication part.

27. The sensor assembly according to claim 26, characterized in that The wireless communication part is a Bluetooth communication part.

28. A sensor shipping device, comprising a sensor assembly according to any one of claims 1 to 27, characterized in that: The sensor shipping device also includes a package shaped to receive the sensor assembly and including a magnet in a position in which a magnetic field of the magnet triggers the first switch device if the sensor assembly is positioned in the package.

29. The sensor shipping device according to claim 28, characterized in that: The packaging is arranged to receive the sensor assembly in a predefined position, wherein the magnet is in a position to trigger the first switch arrangement.

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