Detection of a user tapping a device based on RF signal distortions

Abstract

A system (40) for detecting a user tapping a device (41) is configured to obtain one or more received radiofrequency signals which are received or transmitted by the device via an antenna (48) comprised in the device and detect current temporary distortions of the one or more received radiofrequency signals which are caused by a current vibration of the antenna and / or of one or more semi-stationary elements comprised in the device. The current vibration is caused by the device being tapped. The one or more semi-stationary elements are not part of the antenna. The system is further configured to detect whether the user is tapping the device based on a result of the detection.

Description

[0001] DETECTION OF A USER TAPPING A DEVICE BASED ON RF SIGNAL

[0002] DISTORTIONS

[0003] FIELD OF THE INVENTION

[0004] The invention relates to a system for detecting a user tapping a device.

[0005] The invention further relates to a of detecting a user tapping a device.

[0006] The invention also relates to a computer program product enabling a computer system to perform such a method.

[0007] BACKGROUND OF THE INVENTION

[0008] Many types of devices can be controlled with buttons or a touch screen on the device itself, e.g. TVs, monitors, refrigerators, thermostats. However, certain types of devices have no control elements on the device itself, e.g. light bulbs and certain connected luminaires, or have limited control elements on the device itself, e.g. certain types of smart speakers and certain luminaires. A control element on devices that are within reach of the user (e.g. a portable light, a table lamp, a desk lamp) is often appreciated by users, but devices may lack this functionality due to cost. For example, many connected lamps lack this functionality due to cost, or due to lack of space for such control element.

[0009] Control elements on devices normally comprise one or more mechanical input elements and / or one or more touch input elements and / or one or more tap input elements. WO 2017 / 063893 Al describes an example of a device with tap input elements. This device has mechanical push buttons and surfaces of the housing which are designed in such a way that they have a specific vibration signature over time. Vibrations detected by a vibration sensor caused by a user pressing a button or running their finger along a specific portion of the housing are correlated with predetermined vibration signatures of surfaces / buttons to determine which button or surface of the device a user has interacted with. This detected user interaction is then translated to control the device. For example, if the device is a luminaire, the user interaction is translated to light control.

[0010] A drawback of the device described in WO 2017 / 063893 Al is that it requires a dedicated tap-sensing element (e.g. accelerometer) in the device, which may be too costly for certain types of devices or require additional space. SUMMARY OF THE INVENTION

[0011] It is a first object of the invention to provide a system, which is able to detect a user tapping a device in a relatively cheap and / or space-efficient manner.

[0012] It is a second object of the invention to provide a method, which can be used for detecting a user tapping a device in a relatively cheap and / or space-efficient manner.

[0013] In a first aspect of the invention, a system for detecting a user tapping a device comprises at least one receiver and at least one processor configured to obtain one or more received radiofrequency signals via said at least one receiver, said one or more radiofrequency signals being received or transmitted by said device via an antenna comprised in said device, detect current temporary distortions of said one or more received radiofrequency signals which are caused by a current vibration of said antenna and / or of one or more semi-stationary elements comprised in said device, said current vibration being caused by said device being tapped, said one or more semi-stationary elements not being part of said antenna, and detect whether said user is tapping said device based on a result of said detection.

[0014] With more and more devices becoming wirelessly controllable, RF sensing will quickly become a mature sensing technology and a commodity in many applications, e.g. lighting applications. As a result, many RF device processors will continuously or frequently monitor RF signals. Even without RF sensing will certain types of devices, e.g. radar sensors and Wi-Fi devices, continuously or frequently monitor RF signals. This makes it possible to detect taps in a relative cheap and space-efficient manner by monitoring temporary distortions in the received RF signal(s) which are caused by vibrations of the antenna used by the device to transmit and / or receive the RF signal(s) and / or of one or more semi-stationary elements comprised in the device (in proximity of the antenna) when the user taps the device. For example, the system may detect the user tapping the device by detecting instant variations in signal strength.

[0015] The antenna may be made to undergo these vibrations by having it loosely coupled with a surface of the device. The vibration of these one or more semi-stationary elements can be made to cause these temporary distortions by including at least one element made of radiofrequency-affecting material in the one or more semi-stationary elements. The radiofrequency-affecting material may comprise metal or a waterbody, for example. This makes it unnecessary to include a dedicated tap-sensing element (e.g. accelerometer) in the device. Said device may be a lighting device for example. Said device may use RF sensing to detect presence, for example.

[0016] Said at least one processor may be configured to detect said current temporary distortions of said one or more received radiofrequency signals by detecting at least one of a temporary variation in said one or more received radiofrequency signals’ signal strength and / or channel state information, a variation in said one or more received radiofrequency signals’ radio frequency with respect to said one or more received radiofrequency signals’ nominal radio frequency in a pattern consistent with a tap action, and an oscillating doppler shift in said one or more received radiofrequency signals. The channel state information (CSI) may be the measured channel properties of a wireless communication link.

[0017] Said at least one processor may be configured to determine characteristics of said one or more received radiofrequency signals, compare said characteristics of said one or more received radiofrequency signals with stored characteristics of temporary distortions, and detect said current temporary distortions based on a result of said comparison.

[0018] For example, said at least one processor may be configured to ask said user or a different user to tap said device in a certain period, obtain one or more received reference radiofrequency signals via said at least one receiver, said one or more reference radiofrequency signals being received or transmitted by said device via said antenna in said certain period, determine characteristics of said one or more received reference radiofrequency signals, store said characteristics of said one or more received reference radiofrequency signals in a memory as said stored characteristics of temporary distortions, compare said characteristics of said one or more received radiofrequency signals with said stored characteristics of temporary distortions, and detect said current temporary distortions based on a result of said comparison. The stored characteristics of temporary distortions may be indicative of (reference) vibrations of the antenna.

[0019] By letting one or more users train the system which characteristics of temporary distortions of the RF signal(s) correspond to tap actions, the probability that the user tapping the device is detected may be increased. Alternatively or additionally, the stored characteristics of temporary distortions may have been determined and provided by the manufacturer of the device. For example, manufacturer-provided reference characteristics may be used as default but may be finetuned by the user (e.g. by training the system) if the user wants to optimize the system. Manufacturer-provided reference characteristics may also be fine-tuned without asking users to tap the device, e.g. by initially using manufacturer- provided reference characteristics and finetuning these characteristics based on an analysis of the measured frequency spectrum characteristics (e.g., phase noise) when being tapped.

[0020] Alternatively, current temporary distortions of said one or more received radiofrequency signals which are caused by a current vibration of said antenna and / or of said one or more semi-stationary elements may be detected by performing anomaly detection. For instance, persons walking in a room will also create temporary distortions but this will normally occur much more frequent than a tap. An occasional tap resulting in a vibration of around one second with a very specific signature will then be detected as anomaly.

[0021] Anomaly detection may be performed on data that represents the width of the frequency spectrum above -20dB spectrum magnitude, for example. During normal operation the width of the spectrum is limited. When the spectrum width exceeds the average spectrum, an anomaly occurs. The tap results in a vibration of antenna and the width of the spectrum is increased (symmetrical around the 0Hz). Persons entering will only generate positive or negative frequencies matching their velocity (single peak).

[0022] A visual indication may be provided on a surface of said device, said visual indication indicating where said user should tap said device. This increases the probability that the user tapping the device is detected.

[0023] Said at least one processor may be configured to distinguish between different kinds of tap actions. For example, said at least one processor may be configured to determine at least one of a force of a tap action, a direction of said tap action, and a quantity of tap actions based on characteristics of said current temporary distortions, and distinguish between different kinds of tap actions and / or different users based on one or more of said force of said tap action, said direction of said tap action, and said quantity of tap actions. Distinguishing between different kinds of tap actions makes it possible for the user to select from a plurality of control actions by performing a certain kind of tap action. This may be used to distinguish, for example, between soft or hard tap and single or multi-tap and use these as independent control actions. Distinguishing between different users makes it possible to personalize the control action performed when a user taps the device. The at least one processor may be configured to learn different patterns associated with different kinds of tap actions and / or different users.

[0024] Said at least one processor may be configured to distinguish between a first area of a housing of said device being tapped and a second area of said housing of said device being tapped based on said result of said detection. This makes it possible for the user to select from a plurality of control actions by tapping a certain area of the housing. Tapping in different areas may give different resonance in the housing and this may allow these areas to be differentiated and used as independent control actions.

[0025] Said at least one processor may be configured to allow said user or another user to select a control action, associate said control action with a subset of said stored characteristics of temporary distortions, compare said characteristics of said one or more received radiofrequency signals with said subset of said stored characteristics of temporary distortions, and perform said control action upon detecting said user tapping said device based on a result of said comparison of said characteristics of said one or more received radiofrequency signals with said subset of said stored characteristics. This allows users to configure, for example, which independent control action should be performed for which kind of tap action or for which area of the housing. Alternatively, the manufacturer of the device or the system may have pre-configured this behavior.

[0026] Said one or more radiofrequency signals may comprise multiple radiofrequency signals and said at least one processor may be configured to detect a user within a predetermined distance of said device, and increase a rate at which said multiple radiofrequency signals are transmitted while said user is detected within said predetermined distance of said device. For example, if said multiple radiofrequency signals are transmitted such that an average duration of intervals between consecutive ones of the multiple radiofrequency signals is at most one second, good tap detection results may be achieved. A lower rate may be sufficient for other RF sensing applications, even when the user is near the device, or may be sufficient when RF sensing is (temporarily) disabled. The radiofrequency signals may be transmitted with a fixed or variable message spacing. When one or more users are able to train the system which reference changes in signal strength and / or channel state information correspond to tap actions, pattern of messages being transmitted / received may be changed (e.g. more messages) during the training session for optimal detection and training.

[0027] Said at least one processor may be configured to identify said user, obtain a user profile associated with said user, select a control action based on said user profile, and perform said control action upon detecting said user tapping said device. This makes it possible to personalize the control action performed when a user taps the device.

[0028] In a second aspect of the invention, a method of detecting a user tapping a device comprises obtaining one or more received radiofrequency signals, said one or more radiofrequency signals being received or transmitted by said device via an antenna comprised in said device, detecting current temporary distortions of said one or more received radiofrequency signals which are caused by a current vibration of said antenna and / or of one or more semi-stationary elements comprised in said device, said current vibration being caused by said device being tapped, said one or more semi-stationary elements not being part of said antenna, and detecting whether said user is tapping said device based on a result of said detection. Said method may be performed by software running on a programmable device. This software may be provided as a computer program product.

[0029] Moreover, a computer program for carrying out the methods described herein, as well as a non-transitory computer readable storage-medium storing the computer program are provided. A computer program may, for example, be downloaded by or uploaded to an existing device or be stored upon manufacturing of these systems.

[0030] A non-transitory computer-readable storage medium stores at least one software code portion, the software code portion, when executed or processed by a computer, being configured to perform executable operations for of detecting a user tapping a device.

[0031] The executable operations comprise obtaining one or more received radiofrequency signals, said one or more radiofrequency signals being received or transmitted by said device via an antenna comprised in said device, detecting current temporary distortions of said one or more received radiofrequency signals which are caused by a current vibration of said antenna and / or of one or more semi-stationary elements comprised in said device, said current vibration being caused by said device being tapped, said one or more semi -stationary elements not being part of said antenna, and detecting whether said user is tapping said device based on a result of said detection.

[0032] As will be appreciated by one skilled in the art, aspects of the present invention may be embodied as a device, a method or a computer program product. Accordingly, aspects of the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, microcode, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a "circuit", "module" or "system." Functions described in this disclosure may be implemented as an algorithm executed by a processor / microprocessor of a computer. Furthermore, aspects of the present invention may take the form of a computer program product embodied in one or more computer readable medium(s) having computer readable program code embodied, e.g., stored, thereon.

[0033] Any combination of one or more computer readable medium(s) may be utilized. The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of a computer readable storage medium may include, but are not limited to, the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of the present invention, a computer readable storage medium may be any tangible medium that can contain, or store, a program for use by or in connection with an instruction execution system, apparatus, or device.

[0034] A computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium may be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device.

[0035] Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber, cable, RF, etc., or any suitable combination of the foregoing. Computer program code for carrying out operations for aspects of the present invention may be written in any combination of one or more programming languages, including an object oriented programming language such as Java(TM), Smalltalk, C++ or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer, or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider).

[0036] Aspects of the present invention are described below with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor, in particular a microprocessor or a central processing unit (CPU), of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer, other programmable data processing apparatus, or other devices create means for implementing the functions / acts specified in the flowchart and / or block diagram block or blocks.

[0037] These computer program instructions may also be stored in a computer readable medium that can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions stored in the computer readable medium produce an article of manufacture including instructions which implement the function / act specified in the flowchart and / or block diagram block or blocks.

[0038] The computer program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide processes for implementing the functions / acts specified in the flowchart and / or block diagram block or blocks.

[0039] The flowchart and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of devices, methods and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the blocks may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and / or flowchart illustrations, and combinations of blocks in the block diagrams and / or flowchart illustrations, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and computer instructions. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] These and other aspects of the invention are apparent from and will be further elucidated, by way of example, with reference to the drawings, in which:

[0041] Fig. l is a block diagram of a first embodiment of the system;

[0042] Fig. 2 is a block diagram of a second embodiment of the system;

[0043] Fig. 3 shows a third embodiment of the device;

[0044] Fig. 4 is a flow diagram of a first embodiment of the method;

[0045] Fig. 5 is a flow diagram of a second embodiment of the method;

[0046] Fig. 6 is a flow diagram of a third embodiment of the method;

[0047] Fig. 7 is a flow diagram of a fourth embodiment of the method;

[0048] Fig. 8 is a flow diagram of a fifth embodiment of the method;

[0049] Fig. 9 is a flow diagram of a sixth embodiment of the method;

[0050] Fig. 10 is a flow diagram of a seventh embodiment of the method; and

[0051] Fig. 11 is a block diagram of an exemplary data processing system for performing the method of the invention.

[0052] Corresponding elements in the drawings are denoted by the same reference numeral.

[0053] DETAILED DESCRIPTION OF THE EMBODIMENTS

[0054] Fig. 1 shows a first embodiment of the system for detecting a user tapping a device. In the first embodiment of Fig. 1, the system is a lighting system 10 which comprises a bridge 1, e.g. a Philips Hue bridge, and lighting devices 11-13. The bridge 1 detects whether a user is tapping lighting device 11. In the embodiment of Fig. 1, the lighting device 11 is a luminaire. The lighting device 11 comprises a lampshade 35 and a light bulb 33. The light bulb 33 comprises an antenna 48.

[0055] The bridge 1 communicates with lighting devices 11-13, e.g. using Zigbee technology. Lighting devices 11-13 may be Hue lamps, for example. The bridge 1 is connected to the wireless LAN access point 25, e.g. via Ethernet or Wi-Fi. In the example of Fig. 1, a mobile device 21 is also connected to the wireless LAN access point 25, e.g. via WiFi. Mobile device 21 can be used to control the lighting devices 11-13.

[0056] The bridge 1 comprises a receiver 3, a transmitter 4, a processor 5, and a memory 7. The processor 5 is configured to obtain one or more received radiofrequency signals via the receiver 3. The one or more radiofrequency signals are received or transmitted by the lighting device 11 via the antenna 48 comprised in the lighting device 11. The processor 5 is further configured to detect current temporary distortions of the one or more received radiofrequency signals which are caused by a current vibration of the antenna 48, which is caused by the lighting device 11 being tapped, and detect whether the user is tapping the lighting device 11 based on a result of the detection.

[0057] In the embodiment of Fig. 1, the processor 5 is further configured to determine characteristics of the one or more received radiofrequency signals, compare the characteristics of the one or more received radiofrequency signals with stored characteristics of temporary distortions, and detect the current temporary distortions based on a result of the comparison. The stored characteristics of temporary distortions may be indicative of (reference) vibrations of the antenna. In an alternative embodiment, current temporary distortions of the one or more received radiofrequency signals which are caused by a current vibration of the antenna may be detected by performing anomaly detection.

[0058] The antenna 48 has been positioned so as to vibrate when the lighting device 11 is being tapped. The antenna 48 is loosely coupled with a surface of the light bulb 33 and therefore with a surface of the lighting device 11. The lighting device 11 has been constructed, and the light bulb 33 has been positioned, such that tapping the lampshade 35 will bring the complete lighting device 11 and thus the (mechanically loosely coupled and therefore vibration sensitive) antenna 48 in vibration. In other words, the light bulb 33 would pick up the vibrations of the lampshade 35 and doubles as a tap sensor.

[0059] This makes it possible for the bridge 1 to detect whether the user is tapping the lighting device 11 by detecting temporary distortions of RF signals which are caused by a vibration of the antenna 48. This is especially beneficial for luminaires which are within reach of a user, such as a table lamp, a desk lamp, a bedside lamp, or a floor lamp. It may be necessary or beneficial to calibrate the system, as it may not be known in what kind of luminaire the light bulb 33 is mounted. The lighting device 11 may be configured to give visual feedback on the device when the user taps the lighting device 11.

[0060] The vibration sensitive antenna 48 may be constructed by using a flexible antenna (antenna on flexible surface), an antenna mounted on a flexible element (e.g. a spring-like construction), or a mechanical construction with a joint introducing at least one degree of freedom (e.g. similar to a flexible corner flag), for example. The vibration sensitive antenna 48 may be constructed such that it goes into resonance when the lighting device 11 is tapped. This will provide a longer period of RF signal distortion as well as a more unique pattern which can discerned from other signal distortions not related to tapping the lamp. On a surface of the lighting device 11, a visual indication may be provided which indicates where the user should tap the device (to create the largest effect of the tapping on the RF signal).

[0061] In the embodiment of Fig. 1, the one or more received radiofrequency signals comprise RF signals received directly by the bridge 1 from the lighting device 11. The one or more received radiofrequency signals may further comprise RF signals forwarded to the bridge 1 by the lighting device 11 and / or RF signals forwarded to the bridge 1 by the lighting devices 12 and 13. As an alternative to the forwarding of RF signals, the lighting device 11 and / or the lighting devices 12 and 13 may comprise one or more processors configured to determine characteristics of the RF signals received by them and transmit information specifying these characteristics to the bridge 1.

[0062] In an alternative embodiment, the one or more received radiofrequency signals do not comprise RF signals received directly by the bridge 1 from the lighting device 11. In this alternative embodiment, one or more processors of the lighting device 11 and / or the lighting devices 12 and 13 are configured to obtain the one or more received radiofrequency signals and to either detect current temporary distortions of RF signals received by them or to determine characteristics of the RF signals received by them and transmit information specifying these characteristics to the bridge 1. In the latter case, the bridge 1 is configured to detect current temporary distortions of RF signals received by the lighting device(s) based on these characteristics.

[0063] If current temporary distortions are detected of RF signals received by RF devices other than lighting device 11, e.g. lighting devices 12 and 13, from the lighting device 11, and if relative positions of these other RF devices are known, this may be used to detect at which side the lampshade 35 was tapped.

[0064] In the embodiment of Fig. 1, the processor 5 compares the characteristics of the received RF signals with the stored characteristics of temporary signal distortions to detect whether the received RF signals correspond to a tap action or not. For instance, a tap action will cause a temporary variation in signal strength which lasts maximally a few seconds after which the signal instantly returns to its original strength.

[0065] Alternatively, a variation in the RF frequency from its nominal value in a pattern consistent with a tap may be detected. As another alternative sensing principle, so- called CSI measurements may be used to identify frequency shifts in received signals. Oscillating doppler shifts can be a very unique property of a vibrating antenna.

[0066] In a more advanced embodiment than the embodiment of Fig. 1, the light bulb 33 may have multiple or longer antenna segments to enable multiple tap buttons or tap directions (e.g. each representing a light setting). In a more advanced embodiment than the embodiment of Fig. 1, mechanical damping elements (like a layer of glue) may be used to generate a characteristic sustain curve of the mechanical oscillation. With this, also tap pulses from different directions may generate different oscillation sustain shapes.

[0067] In a more advanced embodiment than the embodiment of Fig. 1, different antennas may get different weight-to-length properties to make the mechanical oscillation frequency characteristic. If the antenna is a conductor layer of a printed circuit board (PCB), this may e.g. be done at production time by placing different components or different number of components on the oscillating part of the PCB.

[0068] The user may be allowed to activate and deactivate the tap sensing function (e.g. via a configuration menu in a lighting control app) in order to avoid undesired lighting control triggers (e.g. when picking up a portable light) or because of unreliable RF connectivity causing detection of false positive tap events. Alternatively or additionally, the tap sensing function may only be activated automatically in the commissioning phase of lamps. In this case, the rate at which the wireless messages are transmitted may be increased while the tap sensing function is activated to improve the responsiveness of the system.

[0069] In the embodiment of the bridge 1 shown in Fig. 1, the bridge 1 comprises one processor 5. In an alternative embodiment, the bridge 1 comprises multiple processors. The processor 5 of the bridge 1 may be a general-purpose processor, e.g. ARM-based, or an application-specific processor. The processor 5 of the bridge 1 may run a Unix-based operating system for example. The memory 7 may comprise one or more memory units. The memory 7 may comprise one or more hard disks and / or solid-state memory, for example. The memory 7 may be used to store a table of connected lights, for example.

[0070] The receiver 3 and the transmitter 4 may use one or more wired and / or wireless communication technologies, e.g. Ethernet and / or Wi-Fi (IEEE 802.11), for communicating with the wireless LAN access point 25, for example. In an alternative embodiment, multiple receivers and / or multiple transmitters are used instead of a single receiver and a single transmitter. In the embodiment shown in Fig. 1, a separate receiver and a separate transmitter are used. In an alternative embodiment, the receiver 3 and the transmitter 4 are combined into a transceiver. The bridge 1 may comprise other components typical for a network device such as a power connector. The invention may be implemented using a computer program running on one or more processors.

[0071] Fig. 2 shows a second embodiment of the system for detecting a user tapping a device. In the second embodiment of Fig. 2, the system is a system 40 which comprises only a lighting device 41, e.g. a light bulb. The lighting device 41 detects whether a user is tapping lighting device 41. A bridge 27 communicates with lighting devices 41,12-13, e.g. using Zigbee technology. The bridge 27 is connected to the wireless LAN access point 25, e.g. via Ethernet or Wi-Fi.

[0072] The lighting device 41 comprises a light source 43, a processor 45, a transceiver 46, a memory 47, and an antenna 48. The antenna 48 has been positioned so as to vibrate when the lighting device 41 is being tapped. The antenna 48 is loosely coupled with a surface of the lighting device 41. The processor 45 is configured to obtain one or more received radiofrequency signals via transceiver 46. The one or more radiofrequency signals are received or transmitted by the lighting device 41 via transceiver 46 and the antenna 48.

[0073] The processor 45 is further configured to detect current temporary distortions of the one or more received radiofrequency signals which are caused by a current vibration of the antenna 48. The current vibration is caused by the lighting device 41 being tapped. The processor 45 is further configured to detect whether the user is tapping the lighting device 41 based on a result of the detection. On a surface of the lighting device 41, a visual indication may be provided which indicates where the user should tap the device.

[0074] If the lighting device 41 is a light bulb, the user taps the light bulb directly and the tap sensing function may be used during the installation or configuration process, because at that moment the user is nearby and touching the light bulb already anyway. The lighting device 41 may be configured to give visual feedback on the device when the user taps the lighting device 41.

[0075] In the embodiment of the lighting device 41 shown in Fig. 4, the lighting device 41 comprises one processor 45. In an alternative embodiment, the lighting device 41 comprises multiple processors. The processor 45 of the lighting device 41 may be a general- purpose processor, e.g. ARM-based, or an application-specific processor. The transceiver 46 may use one or more wireless communication technologies, e.g. Zigbee, for communicating with the bridge 27, for example.

[0076] In the embodiment of Fig. 2, a receiver and a transmitter have been combined into a transceiver. In an alternative embodiment, the receiver and the transmitter may be separate components. In the embodiment of Fig. 2, the lighting device 41 comprises a single transceiver. In an alternative embodiment, the lighting device 41 comprises multiple transceivers. The lighting device 41 may comprise other components typical for a connected lighting device such as a power connector and / or a battery. The invention may be implemented using a computer program running on one or more processors. In the embodiment of Fig. 2, the lighting devices 41,12-13 can be controlled by the mobile device 21 via the bridge 27. In an alternative embodiment, one or more of the lighting devices 41,12-13 can be controlled by the mobile device 21 without a bridge, e.g. directly via Bluetooth or via a cloud server.

[0077] An advantage of the embodiment of Fig. 2 over the embodiment of Fig. 1 is that there is a shorter delay between the user tapping the lighting device and the light being adjusted, as the lighting device performs the processing / detection itself. In the embodiment of Fig. 1, after the bridge has performed the processing / detection, it still has to transmit a control message to the lighting device. If the lighting device gives visual feedback on the device when the user taps the device, there is also a shorter delay between the user tapping the lighting device and the visual feedback.

[0078] Fig. 3 shows a third embodiment of the device: a lighting device 61. In this third embodiment, the lighting device 61 comprises a light bulb 63, a lampshade 65, and a plurality of semi-stationary elements 69. In the embodiment of Fig. 3, only the lampshade 65 is vibrating due to taps. The light bulb 69 comprises a fixed antenna 68. Tapping the lamp shade 65 will not result in vibration of the antenna 68. This embodiment does not require the antenna to vibrate since this function is taken over by vibration of the lamp shade. In this embodiment, the vibration sensitive lampshade 65 doubles as a tap sensor.

[0079] The semi-stationary elements 69 are made of radiofrequency-affecting material and have been positioned so as to vibrate when the lighting device 61 is being tapped. The semi-stationary elements 69 are not part of the antenna 68. The radiofrequencyaffecting material of the semi-stationary elements 69 impact the RF signals and vibrations of these semi -stationary elements 69 influence the RF characteristics. The one or more semi- stationary elements may be simple metal parts that are not part of the antenna but would vibrate when tapped and thus influence the RF characteristics, for example.

[0080] The one or more semi-stationary elements 69 may comprise one or more loose elements and / or one or more other semi-stationary elements. These one or more other semi- stationary elements are not loose hanging parts but may be normal metal parts of the lighting device, e.g. metal strips that connect a lampshade to the center or parts of a chandelier that move when the chandelier is touched.

[0081] The embodiment of Fig. 3, in which the lighting device 61 comprises one or more (RF signal distorting) semi-stationary elements near the antenna which will cause dynamic signal distortion upon a tap action, is an alternative to the loosely coupled antenna comprised in the lighting devices 11 and 41 of Figs. 1 and 2, respectively. The material of the lampshade 65 may be such that the effect of vibrations on the RF signal is maximized.

[0082] The one or more semi-stationary elements 69 may be constructed such that they go into resonance when the lampshade 65 is tapped. This will provide a longer period of RF signal distortion as well as a more unique pattern which can discerned from other signal distortions not related to tapping the lampshade 65.

[0083] A variant of the bridge 1 of Fig. 1 may be used to alternatively or additionally detect whether the user is tapping lighting device 61. Assuming that the one or more radiofrequency signals are received or transmitted by the lighting device 61 via the antenna 68, the processor 5 of bridge 1 is configured to obtain the one or more received radiofrequency signals and detect current temporary distortions of the one or more received radiofrequency signals which are caused by a current vibration of the semi-stationary elements 69. The current vibration is caused by the lighting device 61 being tapped.

[0084] The processor 5 is further configured to detect whether the user is tapping the lighting device 61 based on a result of the detection. On a surface of the lighting device 61, a visual indication may be provided which indicates where the user should tap the device.

[0085] In a more advanced embodiment than the embodiment of Fig. 3, the lampshade 65 may be equipped with a secondary antenna which is pumped by the light bulb’s own antenna 68. In this case this secondary antenna may be mechanically designed for certain oscillations. Alternatively, this secondary antenna may be a metal piece which is tuned (in size / shape / di stance to the first antenna) to the RF frequency used by the light bulb 63, causing its vibrations to influence the RF characteristics of the signals transmitted and received by the light bulb 63.

[0086] In a more advanced embodiment, the embodiments of Figs. 1 and 3 are combined. In this embodiment, the lighting device comprises both one or more semi- stationary elements which vibrate when the lighting device is being tapped and an antenna which vibrates when the lighting device is being tapped.

[0087] In the embodiments of Figs. 1-3, the system detects whether a user is tapping a lighting device. In an alternative embodiment, the system detects whether a user is tapping a different kind of device, e.g. a smart speaker.

[0088] A first embodiment of the method of detecting a user tapping a device is shown in Fig. 4. The device may be a lighting device, for example. The method may be performed by the system 10 of Fig. 1 or the system 40 of Fig. 2, for example. A step 101 comprises obtaining one or more received radiofrequency signals. The one or more radiofrequency signals are received or transmitted by the device via an antenna comprised in the device. The one or more radiofrequency signals may comprise, for example, multiple radiofrequency signals which are transmitted such that an average duration of intervals between consecutive ones of the multiple radiofrequency signals is at most one second. The radiofrequency signals may be transmitted with a fixed or variable message spacing.

[0089] A step 103 comprises detecting current temporary distortions of the one or more received radiofrequency signals which are caused by a current vibration of the antenna and / or of one or more semi-stationary elements comprised in the device. The current vibration is caused by the device being tapped. The one or more semi-stationary elements are not part of the antenna.

[0090] Step 103 may comprise detecting one or more of a temporary harmonic variation in the one or more received radiofrequency signals’ signal strength and / or channel state information, a variation in the one or more received radiofrequency signals’ radio frequency with respect to the one or more received radiofrequency signals’ nominal radio frequency in a pattern consistent with a tap action, and an oscillating doppler shift in the one or more received radiofrequency signals. The channel state information may be the measured channel properties of a wireless communication link.

[0091] Step 103 may, for example, comprise determining characteristics of the one or more received radiofrequency signals, comparing the characteristics of the one or more received radiofrequency signals with stored characteristics of temporary distortions, and detecting the current temporary distortions based on a result of the comparison.

[0092] Alternatively, step 103 may, for example, comprise performing anomaly detection. For instance, persons walking in a room will also create temporary distortions but this will normally occur much more frequent than a tap. An occasional tap resulting in a vibration of around one second with a very specific signature will then be detected as anomaly.

[0093] Anomaly detection involves the identification of observations and patterns that deviate drastically from the expected data. These anomalies, often referred to as anomalies, outliers, discordant observations, exceptions are a minority. Unsupervised anomaly detection algorithms (like isolation forest and autoencoders) learn a representation of normal data to detect rare deviations. Next to learning these representations on existing data, these representations can also be learned online on the incoming sensor data stream. Anomaly detection may be performed on data that represents the width of the frequency spectrum above -20dB spectrum magnitude, for example. During normal operation the width of the spectrum is limited. When the spectrum width ds the average spectrum, an anomaly occurs. The tap results in a vibration of antenna and the width of the spectrum is increased (symmetrical around the 0Hz). Persons entering will only generate positive or negative frequencies matching their velocity (single peak).

[0094] A step 109 comprises detecting whether the user is tapping the device based on a result of the detection of step 103. Additionally, one or more steps of one or more of the embodiments of Figs. 5-10 may be added to the embodiment of Fig. 4.

[0095] A second embodiment of the method of detecting a user tapping a device is shown in Fig. 5. The embodiment of Fig. 5 is an extension of the embodiment of Fig. 4. In the embodiment of Fig. 5, step 109 of Fig. 4 comprises a step 121 and steps 122 and 123 are performed after step 109.

[0096] Step 121 comprises distinguishing between a first area of a housing of the device being tapped and a second area of the housing of the device being tapped based on the result of the detection of step 103. Step 121 may comprise distinguishing between the first area of the housing being tapped on one hand and the second area of the housing or no part of the device being tapped on the other hand or distinguishing between the first area of the housing being tapped, the second area of the housing being tapped, and no part of the device being tapped.

[0097] Step 122 comprises determining whether the user was detected to be tapping the device in step 109. If not, step 101 is repeated, and the method then proceeds as shown in Fig. 5. Step 123 is performed if the user was detected to be tapping the device in step 109. Step 123 comprises performing a control action. Step 101 is repeated after step 123, and the method then proceeds as shown in Fig. 5. Additionally, one or more steps of one or more of the embodiments of Figs. 6-10 may be added to the embodiment of Fig. 5.

[0098] A third embodiment of the method of detecting a user tapping a device is shown in Fig. 6. The embodiment of Fig. 6 is an extension of the embodiment of Fig. 4. In the embodiment of Fig. 6, steps 122, 131, 133, 135, and 123 are performed after step 109 of Fig. 4.

[0099] Step 122 comprises determining whether the user was detected to be tapping the device in step 109. If not, step 101 is repeated, and the method then proceeds as shown in Fig. 6. Step 131 is performed if the user was detected to be tapping the device in step 109. Step 131 comprises determining at least one of a force of a tap action, a direction of the tap action, and a quantity of tap actions based on characteristics of the current temporary distortions detected in step 103.

[0100] Step 133 comprises distinguishing between different kinds of tap actions and / or different users based on one or more of the force of the tap action, the direction of the tap action, and the quantity of tap actions determined in step 131. For example, step 133 may comprise distinguishing between a soft tap, a hard tap and double taps, and / or between taps from different directions and / or between various slide actions. Sliding over the 3D texture of a device surface may induce typical harmonical variations in the RF signal.

[0101] Step 135 comprises selecting a control action for controlling the device from a plurality of control actions based on the kind of tap action identified in step 133. Step 123 comprises performing the control action selected in step 135 by controlling the device according to the control action. For example when a user performs consecutive taps on a lighting device, the light intensity may be increased slightly with each tap, a specific light scene may be selected based on the identified tap action, a light output color may be selected based on the identified tap action, etc. The control action may be selected based on tap actions performed on a combination of devices. For example, tapping a certain combination of lighting devices may be made to trigger a specific scene related to an activity at that moment.

[0102] Step 101 is repeated after step 123, and the method then proceeds as shown in Fig. 6. Additionally, one or more steps of one or more of the embodiments of Figs. 5, 7-10 may be added to the embodiment of Fig. 6. For example, the embodiment of Fig. 6 may be combined with the embodiment of Fig. 7. For instance, an app may ask the user to tap the device in a certain manner, and to repeat this a few times so the system can learn within which thresholds this tap lies and map a user-defined action to it (calibrated to the user).

[0103] A fourth embodiment of the method of detecting a user tapping a device is shown in Fig. 7. The method may be performed by the system 10 of Fig. 1 or the system 40 of Fig. 2, for example. The method of Fig. 7 may be used to finetune or calibrate the exact touch sensing settings to environmental and user characteristics.

[0104] A step 151 comprises asking the user or a different user to tap the device in a certain period. A step 153 comprises obtaining one or more received reference radiofrequency signals. The one or more reference radiofrequency signals are received or transmitted by the device via an antenna comprised in the device in the certain period. A step 155 comprises determining characteristics of the one or more received reference radiofrequency signals obtained in step 153 to enable detection of current temporary distortions in step 103. A step 157 comprises storing the characteristics of the one or more received reference radiofrequency signals, as determined in step 155, in a memory as characteristics of temporary distortions. Steps 151-157 may be performed multiple times.

[0105] Step 101 comprises obtaining one or more received radiofrequency signals. The one or more radiofrequency signals are received or transmitted by the device via the antenna comprised in the device. Step 103 comprises detecting current temporary distortions of the one or more received radiofrequency signals which are caused by a current vibration of the antenna and / or of the one or more semi-stationary elements comprised in the device. The current vibration is caused by the device being tapped.

[0106] In the embodiment of Fig. 7, step 103 is implemented by a step 161. Step 161 comprises comparing the characteristics of the one or more received radiofrequency signals, as obtained in step 101, with the characteristics of temporary distortions stored in step 155, and detecting the current temporary distortions based on a result of the comparison. Step 161 also comprises retrieving the stored characteristics from the memory before performing the comparison.

[0107] Step 109 comprises detecting whether the user is tapping the device based on a result of the detection of step 161. Additionally, one or more steps of one or more of the embodiments of Figs. 5-6,8-10 may be added to the embodiment of Fig. 7. Step 101 is repeated after step 109, and the method then proceeds as shown in Fig. 7. If multiple users are asked finetune or calibrate the exact tap sensing settings in this way, the system could learn to differentiate between taps of different users, e.g. to render personalized light effects based on who is tapping the device. Multiple users may also be asked to finetune or calibrate the exact tap sensing settings in this way even if there is no need to differentiate between taps of different users, e.g. in order to render the same light effect whenever any of these users taps the device.

[0108] A fifth embodiment of the method of detecting a user tapping a device is shown in Fig. 8. The embodiment of Fig. 8 is an extension of the embodiment of Fig. 4. In the embodiment of Fig. 8, steps 122, 171, 173, 175, and 123 are performed after step 107. Step 122 comprises determining whether the user was detected to be tapping the device in step 109. If not, step 101 is repeated, and the method then proceeds as shown in Fig. 8. Step 171 is performed if the user was detected to be tapping the device in step 109.

[0109] Step 171 comprises identifying the user. The user may be identified based on information collected while one or more of steps 101 to 109 were performed. Presence of the user may be detected before the user has tapped the device, e.g. by using RF sensing. Such presence detection may also trigger that messages are transmitted more often, for better detection, as will be described in relation to Fig. 10. The user may be identified, for example, based on an (e.g. Bluetooth) identifier of an approaching or nearby (personal) user device, such as a smartphone or watch. The identifier of the personal device that is closest to the device may be used as identifier of the user or may be used to lookup the identifier of the user. In addition, the sensors of the personal user device may be used to help detect a tap action more reliably (e.g. by detecting proximity, approach or a user movement), especially in case of a wearable device such as a watch.

[0110] Step 173 comprises obtaining a user profile associated with the user identified in step 171. Step 175 comprises selecting a control action based on the user profile obtained in step 173. Step 123 comprises performing the control action selected in step 175. For example, upon detecting a tap on a lighting device, the activated lighting device response (e.g. setting) could be adjusted to a personal user preference. Additionally, one or more steps of one or more of the embodiments of Figs. 4-7,9-10 may be added to the embodiment of Fig. 8. Step 101 is repeated after step 123, and the method then proceeds as shown in Fig. 8. If the user is identifier

[0111] A sixth embodiment of the method of detecting a user tapping a device is shown in Fig. 9. The method may be performed by the system 10 of Fig. 1 or the system 40 of Fig. 2, for example. A step 181 comprises allowing the user or another user to select a control action. A step 183 comprises associating the control action with a subset of stored characteristics of temporary distortions.

[0112] Multiple subsets of stored characteristics may be stored, for example, by the manufacturer of the device, e.g. corresponding to different kinds of tap actions or different areas of the device being tapped. Alternatively, the embodiments of Figs. 7 and 9 may be combined, for example, and steps 181 and 183 may then be performed between steps 157 and 101. In this variant, the subset of stored characteristics with which the user-selected control action is associated in step 183 of Fig. 9 comprises the characteristics of the temporary distortions stored in step 157 of Fig. 7.

[0113] Step 101 comprises obtaining one or more received radiofrequency signals. The one or more radiofrequency signals are received or transmitted by the device via an antenna comprised in the device. Step 103 comprises detecting current temporary distortions of the one or more received radiofrequency signals which are caused by a current vibration of the antenna and / or of one or more semi-stationary elements comprised in the device. The current vibration is caused by the device being tapped. The one or more semi-stationary elements are not part of the antenna.

[0114] In the embodiment of Fig. 9, step 103 is implemented by a step 185. Step 185 comprises comparing the characteristics of the one or more received radiofrequency signals, as obtained in step 101, with stored characteristics of temporary distortions and detecting the current temporary distortions based on a result of the comparison. These stored characteristics comprise the subset of the stored characteristics of temporary distortions associated with the user-selected control action in step 183.

[0115] Step 109 comprises detecting whether the user is tapping the device based on a result of the detection of step 185. Step 122 comprises determining whether the user was detected to be tapping the device in step 109. If not, step 101 is repeated, and the method then proceeds as shown in Fig. 9. Step 187 is performed if the user was detected to be tapping the device in step 109.

[0116] Step 187 comprises selecting a control action from a plurality of control actions based on the result of the comparison of step 185. If the characteristics of the one or more received radiofrequency signals matched the subset of the stored characteristics of temporary distortions associated with the user-selected control action in step 183, then the control action selected by the user in step 181 is selected in step 187. If the characteristics of the one or more received radiofrequency signals matched another subset of the stored characteristics of temporary distortions, then the control action associated with this other subset is selected in step 187.

[0117] Step 123 comprises performing the control action selected in step 187. Step 101 is repeated after step 123, and the method then proceeds as shown in Fig. 9. Additionally, one or more steps of one or more of the embodiments of Figs. 5-8,10 may be added to the embodiment of Fig. 9.

[0118] A seventh embodiment of the method of detecting a user tapping a device is shown in Fig. 10. The embodiment of Fig. 10 is an extension of the embodiment of Fig. 4. In the embodiment of Fig. 10, steps 191, 193, 195, and 197 are performed in parallel with steps 101-109. In the embodiment of Fig. 10, multiple radiofrequency signals are obtained in step 101.

[0119] Step 191 comprises detecting whether a user is within a predetermined distance of the device. This may be detected by using RF sensing, for example. Step 193 comprises determining whether the user was detected to be within the predetermined distance of the device in step 191. If so, step 195 is performed. If not, step 197 is performed. Step 195 comprises setting a first rate at which the multiple radiofrequency signals are transmitted. Step 197 comprises setting a second rate at which the multiple radiofrequency signals are transmitted. The first rate is higher than the second rate. The radiofrequency signals may be transmitted with a fixed or variable message spacing.

[0120] Step 191 is repeated after step 195 or step 197 is performed, and the method then proceeds as shown in Fig. 10. Thus in, the embodiment of Fig. 10, the rate at which the multiple radiofrequency signals are transmitted is increased while the user is detected within the predetermined distance of the device. The frequently sent RF messages enable a more accurate detection of RF signal distortions such as caused by possible tap actions of the user. Additionally, one or more steps of one or more of the embodiments of Figs. 5-9 may be added to the embodiment of Fig. 10.

[0121] Fig. 11 depicts a block diagram illustrating an exemplary data processing system that may perform the method as described with reference to Figs. 4 to 10.

[0122] As shown in Fig. 11, the data processing system 300 may include at least one processor 302 coupled to memory elements 304 through a system bus 306. As such, the data processing system may store program code within memory elements 304. Further, the processor 302 may execute the program code accessed from the memory elements 304 via a system bus 306. In one aspect, the data processing system may be implemented as a computer that is suitable for storing and / or executing program code. It should be appreciated, however, that the data processing system 300 may be implemented in the form of any system including a processor and a memory that is capable of performing the functions described within this specification.

[0123] The memory elements 304 may include one or more physical memory devices such as, for example, local memory 308 and one or more bulk storage devices 310. The local memory may refer to random access memory or other non-persistent memory device(s) generally used during actual execution of the program code. A bulk storage device may be implemented as a hard drive or other persistent data storage device. The processing system 300 may also include one or more cache memories (not shown) that provide temporary storage of at least some program code in order to reduce the quantity of times program code must be retrieved from the bulk storage device 310 during execution. The processing system 300 may also be able to use memory elements of another processing system, e.g. if the processing system 300 is part of a cloud-computing platform.

[0124] Input / output (VO) devices depicted as an input device 312 and an output device 314 optionally can be coupled to the data processing system. Examples of input devices may include, but are not limited to, a keyboard, a pointing device such as a mouse, a microphone (e.g., for voice and / or speech recognition), or the like. Examples of output devices may include, but are not limited to, a monitor or a display, speakers, or the like. Input and / or output devices may be coupled to the data processing system either directly or through intervening VO controllers.

[0125] In an embodiment, the input and the output devices may be implemented as a combined input / output device (illustrated in Fig. 11 with a dashed line surrounding the input device 312 and the output device 314). An example of such a combined device is a touch sensitive display, also sometimes referred to as a “touch screen display” or simply “touch screen”. In such an embodiment, input to the device may be provided by a movement of a physical object, such as e.g. a stylus or a finger of a user, on or near the touch screen display.

[0126] A network adapter 316 may also be coupled to the data processing system to enable it to become coupled to other systems, computer systems, remote network devices, and / or remote storage devices through intervening private or public networks. The network adapter may comprise a data receiver for receiving data that is transmitted by said systems, devices and / or networks to the data processing system 300, and a data transmitter for transmitting data from the data processing system 300 to said systems, devices and / or networks. Modems, cable modems, and Ethernet cards are examples of different types of network adapter that may be used with the data processing system 300.

[0127] As pictured in Fig. 11, the memory elements 304 may store an application 318. In various embodiments, the application 318 may be stored in the local memory 308, the one or more bulk storage devices 310, or separate from the local memory and the bulk storage devices. It should be appreciated that the data processing system 300 may further execute an operating system (not shown in Fig. 11) that can facilitate execution of the application 318. The application 318, being implemented in the form of executable program code, can be executed by the data processing system 300, e.g., by the processor 302. Responsive to executing the application, the data processing system 300 may be configured to perform one or more operations or method steps described herein.

[0128] Various embodiments of the invention may be implemented as a program product for use with a computer system, where the program(s) of the program product define functions of the embodiments (including the methods described herein). In one embodiment, the program(s) can be contained on a variety of non-transitory computer-readable storage media, where, as used herein, the expression “non-transitory computer readable storage media” comprises all computer-readable media, with the sole exception being a transitory, propagating signal. In another embodiment, the program(s) can be contained on a variety of transitory computer-readable storage media. Illustrative computer-readable storage media include, but are not limited to: (i) non-writable storage media (e.g., read-only memory devices within a computer such as CD-ROM disks readable by a CD-ROM drive, ROM chips or any type of solid-state non-volatile semiconductor memory) on which information is permanently stored; and (ii) writable storage media (e.g., flash memory, floppy disks within a diskette drive or hard-disk drive or any type of solid-state random-access semiconductor memory) on which alterable information is stored. The computer program may be run on the processor 302 described herein. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0129] The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of embodiments of the present invention has been presented for purposes of illustration, but is not intended to be exhaustive or limited to the implementations in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the present invention. The embodiments were chosen and described in order to best explain the principles and some practical applications of the present invention, and to enable others of ordinary skill in the art to understand the present invention for various embodiments with various modifications as are suited to the particular use contemplated.

Claims

CLAIMS:

1. A system (10,40) for detecting a user tapping a device (11,41,61), wherein said device (11,41,61) is a lighting device, said system (10,40) comprising: said device comprising an antenna (48,68), at least one receiver (3,46); and at least one processor (5,45) configured to:- obtain one or more received radiofrequency signals via said at least one receiver (3,46), said one or more radiofrequency signals being received or transmitted by said device (11,41,61) via said antenna (48,68),- determine characteristics of said one or more received radiofrequency signals,- compare said characteristics of said one or more received radiofrequency signals with stored characteristics of temporary distortions, said stored characteristics of temporary distortions being indicative of vibrations of said antenna,- detect, based on a result of said comparison, current temporary distortions of said one or more received radiofrequency signals which are caused by a current vibration of said antenna (48) and / or of one or more semi-stationary elements (69) comprised in said device (11,41,61), said current vibration being caused by said device (11,41,61) being tapped, said one or more semi-stationary elements (69) not being part of said antenna (48,68), and- detect whether said user is tapping said device (11,41,61) based on a result of said detection.

2. A system (10,40) as claimed in claim 1, wherein said at least one processor (5,45) is configured to detect said current temporary distortions of said one or more received radiofrequency signals by detecting at least one of a temporary variation in said one or more received radiofrequency signals’ signal strength and / or channel state information, a variation in said one or more received radiofrequency signals’ radio frequency with respect to said one or more received radiofrequency signals’ nominal radio frequency in a pattern consistent with a tap action, and an oscillating doppler shift in said one or more received radiofrequency signals.

3. A system (10,40) as claimed in claim 1 or 2, wherein said at least one processor (5,45) is configured to:- ask said user or a different user to tap said device (11,41,61) in a certain period,- obtain one or more received reference radiofrequency signals via said at least one receiver (3,46), said one or more reference radiofrequency signals being received or transmitted by said device (11,41,61) via said antenna (48,68) in said certain period,- determine characteristics of said one or more received reference radiofrequency signals,- store said characteristics of said one or more received reference radiofrequency signals in a memory (7,47) as said stored characteristics of temporary distortions,- compare said characteristics of said one or more received radiofrequency signals with said stored characteristics of temporary distortions, and- detect said current temporary distortions based on a result of said comparison.

4. A system (10,40) as claimed in claim 2 or 3, wherein said at least one processor (5,45) is configured to:- allow said user or another user to select a control action,- associate said control action with a subset of said stored characteristics of temporary distortions,- compare said characteristics of said one or more received radiofrequency signals with said subset of said stored characteristics of temporary distortions, and- perform said control action upon detecting said user tapping said device (11,41,61) based on a result of said comparison of said characteristics of said one or more received radiofrequency signals with said subset of said stored characteristics.

5. A system (10,40) as claimed in any one of the preceding claims, wherein said at least one processor (5,45) is configured to:- determine at least one of a force of a tap action, a direction of said tap action, and a quantity of tap actions based on characteristics of said current temporary distortions, and- distinguish between different kinds of tap actions and / or different users based on one or more of said force of said tap action, said direction of said tap action, and said quantity of tap actions.

6. A system (10,40) as claimed in any one of the preceding claims, wherein a visual indication is provided on a surface of said device (11,41,61), said visual indication indicating where said user should tap said device (11,41,61).

7. A system (10,40) as claimed in any one of the preceding claims, wherein said at least one processor (5,45) is configured to distinguish between a first area of a housing of said device (11,41,61) being tapped and a second area of said housing of said device(11.41.61) being tapped based on said result of said detection.

8. A system (10,40) as claimed in any one of the preceding claims, wherein said one or more radiofrequency signals comprise multiple radiofrequency signals and said at least one processor (5,45) is configured to:- detect a user within a predetermined distance of said device (11,41,61), and- increase a rate at which said multiple radiofrequency signals are transmitted while said user is detected within said predetermined distance of said device (11,41,61).

9. A system (10,40) as claimed in any one of the preceding claims, wherein said at least one processor (5,45) is configured to:- identify said user,- obtain a user profile associated with said user,- select a control action based on said user profile, and- perform said control action upon detecting said user tapping said device(11.41.61).

10. A system (10,40) as claimed in any one of the preceding claims, wherein said antenna (48) and / or said one or more semi-stationary elements (69) have been positioned so as to vibrate when said device (11,41,61) is being tapped, said antenna (48) being loosely coupled with a surface of said device (11,41,61) and / or said one or more semi-stationary elements (69) comprising at least one element made of radiofrequency-affecting material.

11. A method of detecting a user tapping a device, wherein said device is a lighting device, said method comprising:- obtaining (101) one or more received radiofrequency signals, said one or more radiofrequency signals being received or transmitted by said device via an antenna comprised in said device;- determining characteristics of said one or more received radiofrequency signals;- comparing said characteristics of said one or more received radiofrequency signals with stored characteristics of temporary distortions, said stored characteristics of temporary distortions being indicative of vibrations of said antenna;- detecting (103), based on a result of said comparison, current temporary distortions of said one or more received radiofrequency signals which are caused by a current vibration of said antenna and / or of one or more semi-stationary elements comprised in said device, said current vibration being caused by said device being tapped, said one or more semi -stationary elements not being part of said antenna; and- detecting (109) whether said user is tapping said device based on a result of said detection.

12. A computer program product for a computing device, the computer program product comprising computer program code to perform the method of claim 11 when the computer program product is run on a processing unit of the computing device.

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