Eliminating mirror symmetry and gravity ambiguity from 2D device grids

Abstract

A mechanism for handling mirror symmetry and gravity ambiguity in a grid of two-dimensional devices. The direction of gravity relative to a first device of three devices is determined by a gravity sensor included in the first device. The relative directions of a second and third device relative to the first device are then ascertained. The direction of gravity and the relative directions of the first and third devices are then used to determine the handedness of a triangle connecting the three devices relative to gravity. This handedness relative to gravity can be propagated throughout a grid of devices and used to eliminate mirror symmetry and gravity ambiguity in the grid.

Description

TECHNICAL FIELD

[0001] The present invention relates to the field of device commissioning, and in particular to determining the orientation of a set of devices with respect to gravity. BACKGROUND

[0002] The introduction of smart devices such as luminaires or lamps into a wide variety of environments (e.g. home environments, industrial environments or clinical environments) is becoming of increasing interest. It is often attempted to define a grid or network to define the relative positions of the devices with respect to each other. In particular, it will be appreciated that the devices can form a hypothetical device grid, each device representing a node of the grid. Determining information about the grid facilitates proper control of the devices as a collective and / or proper control of the devices individually, e.g. to know how to optimally route communication to a particular device, or how to control the device grid to create a desired collective output.

[0003] Commissioning of devices is often a tedious process. This is because an individual often has to tell the system where the devices are, e.g. by pointing a remote control at a luminaire and waiting until it flashes, or by very accurately noting which device went where. It would be advantageous to facilitate automation of this process.

[0004] Automated commissioning processes are under development in which the shape of a device grid (where each device forms a node) can be retrieved, possibly based on RSSI, time of flight, or similar distance response measurements between devices. However, these methods still leave several degrees of freedom for defining the position and orientation of the grid (and thus each device) in absolute space. See for example US20100231404A1.

[0005] It is therefore desirable to facilitate the automatic acquisition of additional properties of the device grid and / or the devices themselves. SUMMARY

[0006] The invention is defined by the claims.

[0007] According to an example of an aspect of the invention, there is provided a computer- implemented method for defining the handedness of a hypothetical triangle connecting a set of three devices with respect to gravity.

[0008] The computer-implemented method comprises: defining a direction of gravity relative to a first device from a gravity sensor associated with the first device and comprised by the first device; obtaining, from an electromagnetic detector arrangement associated with the first device of a set of three devices: a first indicator indicative of a relative direction of a second device of the set of three devices relative to the first device, wherein the second device is configured to output electromagnetic energy detectable by the electromagnetic detector arrangement; and a second indicator indicative of a relative direction of a third device relative to the first device, wherein the third device is configured to output electromagnetic energy detectable by the electromagnetic detector arrangement; and defining a handedness of a hypothetical triangle relative to gravity by processing the direction of gravity relative to the first device, the first indicator and the second indicator.

[0009] The handedness or chirality of the triangle connecting the three devices relative to gravity facilitates identifying the orientation of the triangle (and, by extension, a grid containing the triangle) relative to gravity. The handedness relative to gravity is the handedness relative to a view from a position vertically above the triangle and looking in the direction of gravity. This reduces the number of unidentifiable degrees of freedom left by an automatic commissioning process for commissioning a grid containing three devices.

[0010] In the context of the present disclosure, a hypothetical triangle is defined by a path that starts at a first device, moves to a second device, moves to a third device before returning to the first device. The handedness of the hypothetical triangle defines whether the path moves clockwise or counterclockwise within a plane containing the triangle.

[0011] The present disclosure proposes a method in which the handedness of a hypothetical triangle (connecting three devices) is defined or determined relative to gravity. This facilitates identifying a missing feature of existing commissioning methods.

[0012] Thus, in aspects, the defined and / or determined handedness, as defined in the present application, can be used and / or implemented in an automatic commissioning process associated with a set of three devices. For example, a processing system arranged for automatic commissioning of the set of three devices can be configured to receive or retrieve the handedness for commissioning the set of three devices.

[0013] Thus, in aspects of the present application, only the first device can comprise a gravity sensor defining a direction of gravity relative to the first device.

[0014] Optionally, the second and third devices each comprise one or more light emitting elements, and the electromagnetic detector arrangement associated with the first device is a light sensitive arrangement. The electromagnetic detector can be a photodiode arrangement.

[0015] The second and third devices can each comprise one or more radio frequency transmitting elements, and the electromagnetic detector arrangement associated with the first device can be a radio sensitive arrangement.

[0016] The second and third devices can each comprise one or more microwave frequency transmitting elements, and the electromagnetic detector arrangement with the first device can be a microwave sensitive arrangement.

[0017] In some examples, the electromagnetic detector arrangement associated with the first device comprises a set of three or more electromagnetic detectors configured or positioned to have different angular responses, such that the measured magnitude of incident electromagnetic energy transmitted from the same source is different for each electromagnetic detector.

[0018] Optionally, the second and third devices are each configured operable to output a unique electromagnetic energy pattern and / or frequency to the set of three devices, and the electromagnetic detector arrangement is configured to distinguish the electromagnetic patterns and / or frequencies from one another.

[0019] In some examples, each device is configured to output visible light, and each unique electromagnetic energy pattern and / or frequency comprises an optical coded message unique to the set of three devices.

[0020] In some examples, the second and third devices are each configured operable in at least two modes, the at least two modes comprising: a commissioning mode in which the device outputs a unique electromagnetic energy pattern and / or frequency to the set of three devices; and a run mode in which the device is not capable of outputting a unique electromagnetic energy pattern and / or frequency to the set of three devices.

[0021] A computer-implemented method is also presented for determining the handedness of a plurality of hypothetical triangles forming a polygonal mesh in a single plane, wherein each hypothetical triangle connects three devices together and each hypothetical triangle forms a different face of the polygonal mesh, relative to gravity, the computer-implemented method comprising: performing as previously described to determine the handedness of a first triangle of the mesh relative to gravity; and for each other hypothetical triangle of the mesh, determining the handedness of that hypothetical triangle relative to gravity based on the handedness of the first triangle.

[0022] The single plane can be a non-vertical plane. In some examples, the single plane is a ceiling plane to which and / or on which the devices are connected and / or mounted. The single plane can be horizontal. In aspects, the single plane can be expressed as a flat plane.

[0023] A computer program product comprising computer program code means which, when executed on a computing device having a processing system, causes the processing system to perform all the steps of any of the methods described herein is also presented.

[0024] A processing system for defining a handedness of a first hypothesized triangle connecting a set of three devices with respect to gravity is also presented, the processing system being configured to define a direction of gravity with respect to a first device from a gravity sensor associated with and comprised by the first device; obtain, from an electromagnetic detector arrangement associated with the first device of the set of three devices: a first indicator indicative of a relative direction of a second device of the set of three devices with respect to the first device, wherein the second device is configured to output electromagnetic energy detectable by the electromagnetic detector arrangement; and a second indicator indicative of a relative direction of a third device with respect to the first device, wherein the third device is configured to output electromagnetic energy detectable by the electromagnetic detector arrangement; and define a handedness of a first hypothesized triangle connecting the three devices with respect to gravity by processing the direction of gravity with respect to the first device, the first indicator and the second indicator.

[0025] A system comprising: the processing system described previously and at least one device of the set of three devices connected by the first hypothesized triangle, wherein the at least one device comprises at least the first device comprising the processing system, and wherein the first device comprises the gravity sensor is also presented.

[0026] A system comprising: the processing system described previously; and the set of three devices connected by the first hypothesized triangle is also presented.

[0027] A processing arrangement for determining an orientation of a grid of devices with respect to gravity, wherein each device is configured to output electromagnetic energy and the grid is formed by a plurality of hypothesized triangles connecting the devices together, the processing arrangement comprising: the processing system described previously, wherein the first hypothesized triangle is one of the hypothesized triangles of the grid; and a second processing system configured to determine, for each hypothesized triangle of the grid, a handedness of the hypothesized triangle with respect to gravity based on the handedness of the first hypothesized triangle is also presented.

[0028] A system comprising: the processing arrangement described previously; and the grid of devices is also presented.

[0029] These and other aspects of the application will be apparent from and elucidated with reference to the embodiments described hereinafter. BRIEF DESCRIPTION OF DRAWINGS

[0030] For a better understanding of the present application, and to show more clearly how it can be carried into effect, reference will now be made, by way of example only, to the accompanying drawings in which:

[0031] Figure 1 Two possible orientations of a grid of devices are shown;

[0032] Figure 2 A method according to an embodiment is shown;

[0033] Figure 3 A method according to an embodiment is shown;

[0034] Figure 4 Another method according to an embodiment is shown; and

[0035] Figure 5 A system is shown. DETAILED DESCRIPTION

[0036] The application will be described with reference to the drawings.

[0037] It should be understood that the detailed description and specific examples, while indicating exemplary embodiments of apparatuses, systems and methods, are intended for purposes of illustration only and are not intended to limit the scope of the present application. These and other features, aspects, and advantages of the apparatuses, systems and methods of the present application will become better understood from the following description, appended claims, and accompanying drawings. It should be understood that the drawings are only schematic, and that they are not drawn on a precise scale. It should further be understood that in all drawings, like reference numerals are used to designate corresponding or identical elements.

[0038] The present application provides a mechanism for handling mirror symmetry and gravity ambiguity in a two-dimensional grid of devices. The direction of gravity is determined with respect to a first device of the three devices. The relative directions of the second and third devices with respect to the first device are then ascertained. The direction of gravity and the relative directions of the first and third devices are then used to determine the handedness of the triangle connecting the three devices with respect to gravity. This handedness with respect to gravity can be propagated throughout the grid of devices and used to eliminate mirror symmetry and gravity ambiguity in the grid.

[0039] Embodiments are based on the recognition that by establishing the handedness of all triangles forming a grid of devices with respect to gravity, additional potential degrees of freedom in the grid of devices can be eliminated or ascertained.

[0040] Examples of embodiments disclosed herein can be used in any scenario where devices located in the same plane are to be commissioned. The devices can for example perform an automatic commissioning procedure, where the chirality is relevant to be determined. Suitable scenarios include commissioning of luminaires or light fixtures in the ceiling or connected to the ground. Another example can include a grid of sprinklers (e.g. fire sprinklers) for a garden or outdoor area or for a ceiling. Yet another example can include a set of loudspeakers located at the same height within a room. Yet other examples of suitable devices include PIR sensors, fire sensors, sound level sensors and thermopile sensors, temperature / humidity sensors, etc. A combination of any of the aforementioned devices or sensors can be used.

[0041] For the purpose of the present disclosure, the term "counterclockwise" is considered to be interchangeable with "anti-clockwise" or "anticlockwise". The term "higher" means higher with respect to gravity.

[0042] Figure 1 The problem solved by the disclosed embodiments is demonstrated. Figure 1 A 2D grid 10 of devices 11, 12, 13, 14, 15, 16 is shown, which are interconnected by means of triangles. Each triangle connects three devices together and adjoins at least one other triangle. The triangles do not overlap each other, such that the assumed triangles represent the faces of a polygonal grid connecting the devices together.

[0043] Methods for determining the shape of the grid 10 (i.e. setting up the assumed triangles) are well established in the art. Purely by way of example, the shape of the grid of devices can be derived based on RSSI, time of flight, or similar distance response measurements between the devices. It is not necessary to describe these methods in detail, as they are well established. Such a description will be omitted for the sake of brevity.

[0044] However, it is recognized herein that one disadvantage of known methods for determining the shape of the grid is that the chirality or handedness of the triangles and / or the grid in such a shape is unknown. This means that it is not possible to accurately commission the grid of devices, i.e. to establish the spatial and positional relationships between the devices.

[0045] This disadvantage can best be illustrated by Figure 1 It is shown that Figure 1Two scenarios 101, 102 of a grid of devices 10 lying in a single plane are shown. In each scenario, the direction of gravity remains constant (e.g. into the page). It can also be seen how the shape of the grid is identical in each scenario. However, the grid is mirrored about one of the devices between the two scenarios, while keeping the same shape. Thus, by mirroring the grid across a line lying within the single plane, it is possible to flip / change the gyrotropism or chirality of the grid.

[0046] Thus, there is an unresolved degree of freedom in the positioning of the grid, which prevents or hinders automatic onboarding initialization of the grid of devices 10.

[0047] The proposed embodiments overcome this problem by establishing the gyrotropism or chirality of the triangles with respect to gravity. In this way, it is possible to distinguish in which of the two mirrored orientations (shown in scenarios 101, 102) the grid lies. This approach, for example, avoids the need to determine the direction of gravity individually for each device (e.g. using a respective gravity sensor).

[0048] The proposed embodiments define each triangle as a path starting at a first device, moving to a second device, and then moving to a third device before returning to the first device. For each of the following references, the triangle can be defined using the notation A-B-C, which indicates the triangle defined by the path starting at device A, then moving to device B, and then moving to device C before returning to device A.

[0049] As an example, Figure 1 A first triangle or path 110 is shown (for each scenario), which moves from a first device 11 to a second device 12, from the second device 12 to a third device 13, and then from the third device 13 to the first device 11. The first triangle will have the notation 11-12-13. It can be seen how, in the first scenario 101, the path / triangle 11-12-13 has a clockwise gyrotropism or chirality. In the second scenario 102, the path / triangle 11-12-13 has an anticlockwise gyrotropism or chirality.

[0050] Thus, the gyrotropism of a path with respect to gravity (in the shown example: into the page) can define or characterize in which orientation the grid of devices containing said path is positioned.

[0051] It is also recognized herein that, due to the nature of the polygonal grid formed by the plurality of hypothetical triangles, once the gyrotropism of one triangle is determined, it is possible to determine the gyrotropism of all other triangles in the polygonal grid (i.e. through a simple propagation technique). This is possible because the shape of the grid of devices is known and fixed.

[0052] For example, if the first triangle is defined as 11-12-13 and the second triangle is defined as 12-13-14, then the second triangle must have a counter-clockwise handedness or chirality in the first scenario 101 and a clockwise handedness or chirality in the second scenario 102.

[0053] Similarly, if the first triangle is defined as 11-12-13, but the second triangle is defined as 13-12-14, then the second triangle must have a clockwise handedness or chirality in the first scenario 101 and a counter-clockwise handedness or chirality in the second scenario 102.

[0054] Thus, the proposed method facilitates identifying the relative positions of all devices with respect to other devices in the same assumed triangle of the grid. If the direction of gravity with respect to one of the devices is known, then the overall orientation of the grid with respect to gravity can be easily determined, thereby eliminating mirror symmetry and gravity ambiguity from the device grid 10.

[0055] Figure 2 A method for defining the handedness of an assumed triangle 201-202-203 connecting three devices 201, 202, 203 with respect to gravity is shown. The method can be employed by a computer-implemented method and / or processing system according to various embodiments of the invention.

[0056] The proposed method defines the handedness of a triangle with respect to gravity in a plane having an upper surface / face with a normal making an angle >90° and <=180° (e.g. 180°) with the direction of gravity and a lower surface / face with a normal making an angle >=0° and <90° (e.g. 0°) with the direction of gravity. The handedness is defined from a top view of the plane (i.e. a view from a position above the plane and looking in the direction of gravity).

[0057] Each device 201, 202, 203 can be a device configured for onboarding (e.g. into the Internet of Things). Thus, each device can comprise a communication module (not shown) for wired / wireless communication and external control or activation. In some examples, each device is a luminaire and comprises a light emitting element (e.g. a LED arrangement) configured to output light. The communication module can receive a communication for controlling one or more properties of the light emitting element. The one or more properties can comprise a color, a temperature, an intensity, an angle, a frequency, a diffusion, etc. of the light output by the light emitting element.

[0058] The direction of gravity of at least one device 201 (first device 201) is defined.

[0059] In some examples, this is performed based on prior knowledge. For example, if it is known that a device can only be installed in certain orientations (e.g. installed in a ceiling downlight slot), the direction of gravity relative to the device can be ascertained or defined in advance.

[0060] As mentioned, the direction of gravity is defined using a gravity sensor 210 associated with the first device.

[0061] The gravity sensor 210 is configured to determine the direction of gravity relative to the first device 201. Suitable examples of gravity sensors include accelerometers or gravimeters.

[0062] The first device comprises an electromagnetic detector arrangement. The electromagnetic detector arrangement 220 is configured to determine / obtain: a first indicator indicative of a relative direction of a second device in the set of three devices relative to the first device; and a second indicator indicative of a relative direction of a third device relative to the first device. The electromagnetic detector arrangement 220 thereby acts as an angle detector.

[0063] The electromagnetic detector arrangement 220 is therefore effectively triangulating the second and third devices in a triangle. In particular, the electromagnetic detector arrangement 220 determines from the perspective of the first device the relative positioning of the second and third devices to each other (e.g. which of the second and third devices is on the left and right of the 180° viewpoint).

[0064] The electromagnetic detector arrangement can be located on or within the first device. For example, if the first device is a luminaire located in a ceiling, the electromagnetic detector arrangement can be positioned to be located above the ceiling level. In such examples, the first device can comprise a small aperture or partially / fully transparent region to allow electromagnetic energy to pass to the electromagnetic detector arrangement.

[0065] The second device 202 and third device 203 are both configured to output electromagnetic energy that can be detected or sensed by the electromagnetic detector arrangement. The second device can therefore comprise a first electromagnetic output element 232 that outputs first electromagnetic energy E1, and the third device can comprise a second electromagnetic output element 233 that outputs second electromagnetic energy E2.

[0066] In the example shown, the electromagnetic detector arrangement 220 comprises (at least) three electromagnetic detectors A, B, C that are positioned approximately or substantially in the same plane. This plane is the same as the plane in which the hypothetical triangle 201-202-203 lies.

[0067] Each detector of the arrangement 220 can be configured to generate a signal in response to the intensity of the received electromagnetic energy El, E2 output by each other device 202, 203 multiplied by a different angular response factor. Thus, each detector is configured or positioned to have a different angular response, such that the measured magnitude of incident electromagnetic energy transmitted from the same source is different for each electromagnetic detector. This facilitates triangulation of the source of incident electromagnetic energy, i.e. the second and third devices. The angular response of each detector is such that the measured magnitude (by the detector) of incident electromagnetic energy varies depending on the direction of the incident electromagnetic energy.

[0068] In some examples, the detectors can be configured to receive electromagnetic energy from the same number of directions, but where the sensitivity of each sensor is different (for each of the multiple angles of arrival). Thus, each detector has an angular sensitivity pattern, where the angular sensitivity pattern of different detectors is different. However, the distribution of sensitivity should have some overlap with the adjacent sensors. The ratio of the sensed signals produced by each detector that show the pattern / frequency from each transmitter can then be processed to determine each angle of arrival.

[0069] For example, the detectors can be arranged on a vertical line, and pointing around the vertical axis at 0°, 120° and 240°. These directions represent the maximum response directions. If each detector has a symmetric angular sensitivity fall-off that is zero at +120° and -120° relative to this maximum response direction, and has zero sensitivity outside these angles, then the angle of arrival of electromagnetic energy to the detector arrangement 220 can be easily retrieved.

[0070] It will be appreciated that the signals of all electromagnetic detectors in the arrangement 220 can be processed to generate a ratio of the strength of the detector signals for each of the second and third devices. These ratios of strength can be used to perform a triangulation of the second and third devices relative to the first device, in accordance with accepted triangulation principles.

[0071] Although in the example shown the electromagnetic detector arrangement comprises only three electromagnetic detectors, it will be appreciated that the arrangement can comprise additional electromagnetic detectors, for example to improve angular accuracy or to compensate for limited angular sensitivity of the sensors.

[0072] The previously described electromagnetic detector arrangement relies on a triangulation mechanism to determine the relative direction of the second and third devices. Alternative examples can utilize a triangulation mechanism to determine the relative direction(s).

[0073] Alternatives to the illustrated electromagnetic detector arrangement will be clear to the skilled person, such as a camera (which can detect the relative direction of emitted light), a quadrant detector, or a suitably configured position sensitive device. The precise nature of the electromagnetic detector arrangement can depend on the nature and / or frequency of the electromagnetic energy.

[0074] To distinguish between electromagnetic energy emitted by the second and third devices, the second and third devices can be configured to output electromagnetic energy via the electromagnetic output elements with a unique pattern and / or frequency (for the set of three devices). For example, different devices can output electromagnetic energy carrying (optionally encoded) identifiers, e.g. via CDMA or the like. As another example, frequency division multiplexing can be used to distinguish between electromagnetic energy emissions that are different from each other.

[0075] Alternatively, the second and third devices can be configured to emit electromagnetic energy at different points in time. This can be performed, e.g., using a time division multiplexing approach or a queuing system.

[0076] The first and second indicators facilitate determining the chirality of the hypothetical triangle 201-202-203. This is because the first and second indicators facilitate identifying the left-right order of the second and third devices relative to the front of the electromagnetic detector arrangement, and thereby the chirality of the triangle 201-202-203.

[0077] The chirality is defined relative to the direction of gravity determined for the first device. In particular, the chirality is defined from an observation direction parallel to the direction of gravity. This facilitates identifying the orientation of the triangle 201-202-203 relative to gravity, thereby removing mirror symmetry and gravity ambiguity from the triangle connecting the set of three devices.

[0078] The electromagnetic detector arrangement 220 and the electromagnetic output elements 232, 233 complement each other, e.g. to detect and output, respectively, the same type of electromagnetic energy. Suitable examples of electromagnetic energy include visible light, radio waves, microwaves, etc. In some examples, the electromagnetic energy is emitted in accordance with a predefined communication protocol or standard, e.g. in accordance with a protocol under IEEE 802.11, a protocol under IEEE 802.15.4, Bluetooth®, ZigBee®, or a mobile phone standard (e.g. 3G, 4G, 5G, etc.).

[0079] In preferred examples, the electromagnetic detector arrangement 220 and the electromagnetic output elements are configured to utilize visible light. This is particularly advantageous in examples where the devices are lighting elements or luminaires, which will typically be located in the same plane (e.g. on a ceiling). In these examples, the electromagnetic detector arrangement can comprise a plurality of photodetectors, e.g. photodiodes or photoresistors.

[0080] ​It has been explained previously how, once the handedness or chirality of one triangle (in the mesh) is determined, this information can be propagated throughout the mesh to determine the handedness of all triangles in the mesh relative to gravity.

[0081] This information can be used to establish the most likely orientation of the complete mesh of devices relative to gravity.

[0082] The information about the chirality or handedness or handedness of all triangles can be used to generate or predict or obtain an overhead view (or, if desired, a downward view) drawing of the mesh of devices that can be used for commissioning.

[0083] As an explanation, if triangle 201-202-203 is determined to have a clockwise chirality as shown, it can be determined that, from the perspective of device 201, device 202 is to the left of device 203, and similarly, device 203 is to the right of device 202.

[0084] Since the handedness or chirality of all triangles in the mesh is known, for a particular device, the relative position of each other device in any triangle that the particular device is in can be easily determined. In this way, a top-down view / drawing of the mesh can be easily determined.

[0085] The proposed method for determining the triangle chirality (using a detector arrangement, for example, rather than by propagating the determined chirality) can be performed for multiple triangles of the mesh.

[0086] If the process for determining the triangle chirality of devices (using a detector arrangement) is performed for multiple triangles of the mesh, the information about the handedness / chirality and / or the drawing of all triangles can also be used to correct and / or verify the shape of the mesh of devices that has been previously derived or predicted. In particular, if there is an inconsistency between different handedness calculations for the same triangle, the shape of the mesh of devices can be updated.

[0087] Note that the proposed method leaves one degree of freedom (rotation about the vertical axis) unresolved while resolving one degree of freedom. This further degree of freedom can be resolved using another method, for example, by determining the absolute position of two devices in the mesh, thereby fixing or determining the absolute position of the mesh.

[0088] The operation of the devices can be controlled by a processing arrangement (not shown). The processing arrangement is capable of sending information to the mesh of devices and receiving information from the mesh of devices. The processing system can perform the necessary actions for determining the handedness of a triangle (e.g., based on information received from the devices).

[0089] Figure 3A method 300 for defining a handedness of a hypothetical triangle connecting three devices with respect to gravity is shown. The method is computer-implemented.

[0090] The method 300 comprises a step 310 of defining a direction of gravity with respect to a first device. The step 310 can comprise obtaining the direction of gravity with respect to the first device from a gravity sensor associated with the first device of the set of three devices.

[0091] The method 300 further comprises a process 320 of obtaining, from an electromagnetic detector arrangement associated with the first device of the set of three devices: a first indicator indicative of a relative direction of a second device of the set of three devices with respect to the first device, wherein the second device is configured to output electromagnetic energy detectable by the electromagnetic detector arrangement; and a second indicator indicative of a relative direction of a third device with respect to the first device, wherein the third device is configured to output electromagnetic energy detectable by the electromagnetic detector arrangement.

[0092] The first indicator can be obtained in a first sub-step 321 and the second indicator can be obtained in a second sub-step 322.

[0093] The method 300 further comprises a step 330 of defining a handedness of a hypothetical triangle connecting the three devices with respect to gravity by processing the direction of gravity with respect to the first device, the first indicator and the second indicator. Methods for defining the handedness using the first and second indicators have been described previously, and suitable examples of the first and second indicators have been described.

[0094] The method 300 can be performed by a processing system capable of communicating with at least the first device of the grid of devices, e.g. to receive the first indicator, the second indicator and the direction of gravity. In particular, the method 300 can be performed by a processing system configured for (auto-) commissioning of the grid of devices, e.g. to communicate with all devices of the grid of devices.

[0095] Figure 4 A method 400 for commissioning a grid of devices according to an embodiment is shown. The method is computer-implemented.

[0096] The method 400 comprises a step 410 of determining a shape of the grid of devices. Methods for determining a shape of a grid of devices are well-established in the art. Typically, such a method comprises measuring mutual signal strengths (RSSI) between all devices to form a link strength matrix. A multidimensional scaling (MDS) technique can then be performed to transform the link strength matrix to generate a 2D grid of triangles linking all devices together. Each vertex of the 2D grid represents a different device.

[0097] From this, the 2D grid is formed of a plurality of hypothetical triangles, where each hypothetical triangle connects three devices together, and each hypothetical triangle forms a different face of the polygonal grid. Thus, different triangles abut each other without overlapping.

[0098] The method 400 can then perform a process 420 for determining the handedness of the triangles of the grid with respect to gravity. The process 420 is itself an embodiment.

[0099] The process 420 comprises performing the previously described method 300 to determine the handedness of a first triangle of the grid with respect to gravity. The process 420 then performs a step 425 of determining, for each other hypothetical triangle of the grid, the handedness of that hypothetical triangle with respect to gravity based on the handedness of the first triangle.

[0100] The step 425 is achieved by propagating the determined handedness of the first triangle throughout the remainder of the grid. Methods for performing the propagation will be readily apparent to the skilled person.

[0101] To improve redundancy, the method 300 can be performed a plurality of times on different triangles of the grid. In particular, there can be more than one device with a gravity sensor and electromagnetic detector arrangement to facilitate identification of the handedness of other triangles in the grid. The step 425 can be adapted to propagate all determined handedness throughout the network.

[0102] The method 400 can then perform an (optional) step 430 of updating or correcting the structure of the grid based on the determined handedness. In particular, if there are any inconsistencies in the calculation of the handedness, then the shape of the structure can be corrected.

[0103] The method 400 then performs a step 440 of determining or predicting the orientation of the grid with respect to gravity. This can be achieved because the handedness of all triangles with respect to gravity has previously been determined, so that the most likely orientation of the grid can be readily derived.

[0104] The step 440 alternatively or additionally comprises generating an overhead view (or, if desired, an underfoot view) plot of the device grid. The overhead view is a view from above the device grid in the direction of gravity. This can be achieved because the relative handedness of all triangles effectively defines the relative positioning between the devices. Since the shape of the grid is known, this facilitates the precise positioning of the devices relative to each other on the plot.

[0105] In some examples, the method can be configured to further comprise the step of deriving the orientation of any device (relative to gravity) that contains an angle sensor and is in a triangle of the grid with the other two devices that output identifiable electromagnetic energy from the handedness of the triangle in the determined grid relative to gravity.

[0106] This is possible because a consistent indication between the relative direction of the other two devices derived using the angle sensor and the relative direction defined by the handedness of the triangle indicates that the angle sensor (and thus the device) is aligned with gravity. An inconsistency or mismatch indicates that the angle sensor is inverted relative to gravity. This helps to identify the orientation of the device relative to gravity.

[0107] The method 400 then moves to step 450: commissioning the devices. Methods for commissioning a set of devices are well established in the art and can include connecting the appropriate inputs and outputs of each device to the relevant elements of an application program interface (API) and a user interface.

[0108] The commissioning of the devices can be based on the orientation of the devices, the grid and / or the mapping of the grid of devices. This provides valuable information for automating the appropriate commissioning by removing ambiguities about mirror symmetry or the direction of gravity.

[0109] The method 400 can be performed by a processing system capable of communicating with each device in the grid of devices. Suitable wireless communication protocols that can be used to perform this communication include infrared links, ZigBee, Bluetooth, wireless local area network protocols such as according to the IEEE 802.11 standards, 2G, 3G or 4G telecommunication protocols, ultrasonic protocols, and the like. Other formats will be readily apparent to those skilled in the art.

[0110] Figure 5 A system 500 according to an embodiment is shown. The system 500 comprises a grid 510 of devices 511-516 and a processing system arrangement 520. This processing arrangement is also an embodiment.

[0111] The grid 510 comprises three or more devices that can form a polygonal grid of one or more hypothetical triangles, where different triangles are adjacent to each other and do not overlap. To facilitate determining the grid 510, for each device it should be possible to determine the relative distance between that device and at least two other devices (e.g. using the RSSI method).

[0112] The grid of devices 510 is located in a single plane, i.e. to form a two-dimensional grid. This single plane is a non-vertical plane. In particular, the single plane can be a horizontal and / or a ceiling plane to which and / or on which the devices are connected and / or mounted.

[0113] The processing arrangement 520 comprises a first processing system 521 and a second processing system 522. In some examples, the first and second processing systems are the same, in other examples (as shown) they are two separate entities.

[0114] The processing arrangement is communicatively coupled to the device mesh so as to be able to send information to the device mesh and receive information from the device mesh.

[0115] The first processing system is configured for defining a handedness of a hypothetical triangle 511-512-513 connecting three devices 511, 512, 513 with respect to gravity.

[0116] The first processing system 521 is configured to define a direction of gravity with respect to the first device. This can be performed by obtaining the direction of gravity, for example, from a gravity sensor associated with the first device in the set of three devices.

[0117] The first processing system 521 is further configured to obtain, from an electromagnetic detector arrangement associated with the first device 511 in the set of three devices: a first indicator indicative of a relative direction of a second device 512 in the set of three devices with respect to the first device; and a second indicator indicative of a relative direction of a third device 513 with respect to the first device. The first processing system 521 is further configured to determine the handedness of the first hypothetical triangle with respect to gravity by processing the direction of gravity with respect to the first device, the first indicator and the second indicator.

[0118] Thus, the first processing system performs or implements the method 300 with reference to Figure 3 the method 300 described.

[0119] Preferably, each of the second and third devices is configured operable to output a unique electromagnetic energy pattern and / or frequency to the set of three devices, and the electromagnetic detector arrangement is configured to distinguish the electromagnetic patterns and / or frequencies from each other. If the electromagnetic energy is light, this can be performed by appropriate coding of the light patterns.

[0120] In some examples, each of the second and third devices is configured operable in at least two modes, the at least two modes comprising: a commissioning mode in which the device outputs a unique electromagnetic energy pattern and / or frequency to the set of three devices; and a running mode in which the device is not capable of outputting a unique electromagnetic energy pattern and / or frequency to the set of three devices. In particular, the device can be prevented from outputting a unique electromagnetic energy pattern and / or frequency to the set of three devices when operating in the running mode.

[0121] The mode of operation of the devices can be controlled by the processing arrangement 520, e.g. by the first processing system 521. The processing arrangement 520 can control the device(s) to enter the run mode in response to determining the handedness of all triangles of the mesh and / or predicting the orientation of the mesh relative to gravity (i.e. only when determining the handedness of all triangles of the mesh and / or predicting the orientation of the mesh relative to gravity is complete).

[0122] The second processing system 522 is configured to determine, for each hypothetical triangle of the mesh, the handedness of said hypothetical triangle relative to gravity based on the handedness of a first hypothetical triangle. This can be performed by propagating the handedness of the first hypothetical triangle 511-512-513 throughout the mesh 510.

[0123] It has been described previously how the method of determining the handedness of multiple different triangles of a mesh can be adapted (e.g. by the first processing system) in order to improve redundancy. In particular, there can be more than one device for which the direction of gravity can be defined independently (e.g. from a gravity sensor), and which has an electromagnetic detector arrangement in order to facilitate the identification of the handedness of other triangles in the mesh.

[0124] Conflicts between different determined handedness of triangles in the mesh, e.g. conflicts arising from propagating different independently determined handedness of triangles, can be resolved automatically, e.g. by reconstructing the shape of the mesh. This provides an improved mesh shaping mechanism.

[0125] However, it is not necessary to define the direction of gravity independently for all devices in a mesh of devices comprising a gravity sensor. It is recognised herein that it is not necessary for all devices to comprise such an independent direction of gravity (e.g. a separate gravity sensor), whilst still achieving a highly accurate identification of the handedness of all triangles and the orientation of the mesh. This avoids the need for expensive gravity sensors in all devices of the mesh.

[0126] When the other two devices in a triangle comprising an angle sensor output identifiable electromagnetic energy, it is possible to derive or predict the orientation of any device in the triangle from the determined handedness of the triangle relative to gravity in the mesh.

[0127] The angle sensor can be used to identify the relative direction of the other two devices in the triangle. If the relative direction matches the expected relative direction (according to the known handedness of the triangle), this means that the angle sensor (and hence the device) is aligned relative to gravity. If the relative direction does not match the expected relative direction (according to the known handedness of the triangle), this means that the angle sensor (and hence the device) is inverted relative to gravity.

[0128] By way of example, consider a scenario in which: the gravity is in the positive z-direction;Figure 5 The device 514 comprises an angle sensor, and the devices 512 and 513 output identifiable electromagnetic energy. If the orientation of the device 514 is aligned with gravity, the relative direction of the device 512 as detected by the angle sensor will be to the right of the device 513 (based on the handedness of the triangle 513-514-512 as shown). Similarly, if the orientation of the device 514 is inverted relative to gravity, the relative direction of the device 512 as detected by the angle sensor will be to the left of the device 513 (based on the handedness of the triangle 513-514-512 as shown).

[0129] Thus, there can be a third processing system 523 configured to determine, for any device comprising an angle sensor located in a triangle of the grid (where the other two devices of the triangle output identifiable electromagnetic energy), the orientation of the device relative to gravity.

[0130] This provides a method for determining the orientation of a device relative to gravity without the need for a direct gravity sensor (e.g. an accelerometer or gravimeter).

[0131] Each device in the grid of devices can for example be a luminaire or a light emitting element. The electromagnetic energy output by the second and third devices can for example be light energy. The proposed method is particularly suitable for luminaires or light emitting elements, as the cost can be reduced by exploiting existing features or characteristics of such (e.g. light emitting) elements.

[0132] However, embodiments are not limited to luminaires or light emitting elements. Rather, each device can comprise one or more of: a PIR sensor, a fire sensor, a sound level sensor and a thermopile sensor, a temperature / humidity sensor, a light emitting element, a loudspeaker, a sprinkler, and so on. Thus, each device can form any suitable IoT device.

[0133] Examples of suitable devices have been described with reference to Figure 2 and can be used in the system of Figure 5 .

[0134] For the sake of clarity, ordinal numbers (e.g. “first”, “second”, etc.) have been used purely to distinguish different elements from each other, and a reference to a non-“first” (e.g. “second” or “third”) element does not necessarily require the existence of a “first” element. The skilled person will be able to re-label any such elements appropriately (e.g. re-label a “second” element as a “first” element if there is only a second element).

[0135] Those skilled in the art will be able to readily develop processes for implementing any of the methods described herein. Thus, each step of the flowcharts can represent a different action to be taken by a process system, and can be performed by corresponding modules of the process system.

[0136] Any of the process systems described herein can be implemented in numerous ways, with software and / or hardware, to perform the various functions required. A processor is one example of a processing system which employs one or more microprocessors that can be programmed to execute the functions required. The processing system can be implemented with or without employing a processor, and also can be implemented as a combination of dedicated hardware to perform some functions and a processor (e.g., one or more programmed microprocessors and associated circuitry) to perform other functions.

[0137] Examples of processing system components that can be employed in various embodiments of the disclosure include, but are not limited to, conventional microprocessors, application specific integrated circuits (ASICs), and field-programmable gate arrays (FPGAs).

[0138] In various implementations, a processor or processing system can be associated with one or more storage media such as volatile and non-volatile computer memory such as RAM, PROM, EPROM, and EEPROM. The storage media can be encoded with one or more programs that, when executed on one or more processors and / or processing systems, perform a required function. The various storage media can be fixed within a processor or processing system or can be transportable, such that the one or more programs stored thereon can be loaded into a processor or processing system.

[0139] It will be appreciated that the disclosed methods are preferably computer implemented methods. As such, the concept of a computer program product, comprising code means, is also set forth, which enables a process described herein, when said program is run on a processing system such as a computer. Thus, different code portions of a computer program according to an embodiment, code lines or code blocks, can be executed by a processing system or computer to perform any of the methods described herein. In some alternative implementations, the functions noted in the block diagram(s) or flowchart(s) can occur out of the order noted in the figure(s). For example, two blocks shown in succession can in fact be executed substantially concurrently or the blocks can sometimes be executed in reverse order, depending on the functionality involved.

[0140] Variations to the disclosed embodiments can become apparent to those of ordinary skill in the art from a reading of the drawings, the disclosure, and the appended claims. In the claims, the term "comprising" does not exclude other elements or steps, and the indefinite articles "a" or "an" do not exclude a plurality. A single processor or other unit can fulfill the functions of several items recited in the claims. If a computer program is discussed as a separate item in the claims, it can be stored / distributed on a suitable medium, such as an optical storage medium or a solid-state medium supplied together with or as part of other hardware; but can also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems. If the term "adapted to" is used in the claims or the specification it is meant to be equivalent to the term "configured to." Any reference signs in the claims should not be construed as limiting the scope.

Claims

1. A computer-implemented method for determining a handedness of a hypothetical triangle connecting a set of three devices (201, 202, 203) with respect to gravity, wherein the handedness with respect to gravity is a handedness with respect to a view from a position vertically above the hypothetical triangle and looking in the direction of gravity; wherein the hypothetical triangle is defined by a path starting at a first device, moving to a second device, moving to a third device before returning to the first device; and wherein the handedness of the hypothetical triangle defines whether the path moves clockwise or anticlockwise in a plane containing the triangle; wherein the computer-implemented method comprises: defining (310) a direction of gravity with respect to a first device of the set of three devices from a gravity sensor associated with the first device and comprised by the first device; obtaining (320, 321, 322) from an electromagnetic detector arrangement (220) associated with the first device of the set of three devices: a first indicator indicative of a relative direction of a second device of the set of three devices with respect to the first device, wherein the second device is configured to output electromagnetic energy (El) detectable by the electromagnetic detector arrangement, and a second indicator indicative of a relative direction of a third device with respect to the first device, wherein the third device is configured to output electromagnetic energy (E2) detectable by the electromagnetic detector arrangement; and determining (330) the handedness of the hypothetical triangle with respect to gravity by processing the direction of gravity with respect to the first device, the first indicator and the second indicator.

2. The computer-implemented method of claim 1, wherein the second device and the third device each comprise one or more light-emitting elements, and the electromagnetic detector arrangement associated with the first device is a light-sensitive arrangement.

3. The computer-implemented method of claim 1, wherein: the second device and the third device each comprise one or more radio frequency transmitting elements, and the electromagnetic detector arrangement associated with the first device is a radio-sensitive arrangement; or the second device and the third device each comprise one or more microwave frequency transmitting elements, and the electromagnetic detector arrangement with the first device is a microwave-sensitive arrangement.

4. The computer-implemented method of any one of claims 1 to 3, wherein the electromagnetic detector arrangement associated with the first device comprises a set of three or more electromagnetic detectors configured or positioned to have different angular responses, such that a measured magnitude of incident electromagnetic energy emitted from the same source is different for each electromagnetic detector.

5. The computer-implemented method of any one of claims 1 to 3, wherein the second device and the third device are both configured to be operable to output unique electromagnetic energy patterns and / or frequencies to the set of three devices, and the electromagnetic detector arrangement is configured to distinguish the electromagnetic patterns and / or frequencies from one another.

6. The computer-implemented method of claim 5, wherein the second device and the third device are both configured to be operable in at least two modes, the at least two modes comprising: a commissioning mode in which a device is able to output a unique electromagnetic energy pattern and / or frequency to the set of three devices; and a run mode in which a device is not able to output a unique electromagnetic energy pattern and / or frequency to the set of three devices.

7. A processing system (520) for determining a handedness of a first assumed triangle connecting a set of three devices (201, 202, 203) relative to gravity, the processing system being configured to: define (310) a direction of gravity relative to a first device from a gravity sensor associated with and comprised by the first device; obtain (320, 321, 322) from an electromagnetic detector arrangement (220) associated with the first device of the set of three devices: a first indicator indicative of a relative direction of a second device of the set of three devices relative to the first device, wherein the second device is configured to output electromagnetic energy (El) detectable by the electromagnetic detector arrangement, and a second indicator indicative of a relative direction of a third device relative to the first device, wherein the third device is configured to output electromagnetic energy (E2) detectable by the electromagnetic detector arrangement; and determine (330) a handedness of the first assumed triangle connecting the three devices relative to gravity by processing the direction of gravity relative to the first device, the first indicator, and the second indicator.

8. A system comprising: the processing system of claim 7; and at least one device of the set of three devices connected by the first assumed triangle, wherein the at least one device comprises at least the first device, the first device comprising the processing system, and wherein the first device comprises the gravity sensor. ​ ​

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