System and method for automated inspection of proper placement of mosquito nets in human occupied spaces

Abstract

A mosquito net (2) has multiple sound receivers (5A, 5B, 5C, 5D) attached to various locations on the net. A sound transmitter (4) on the mosquito net (2) emits a triggering reference sound, e.g., at ultrasonic frequencies, which is picked up by the various sound receivers (5A, 5B, 5C, 5D) and evaluated for its time delay from the sound receivers (5A, 5B, 5C, 5D) by an analysis system (8, 12, 16), e.g., including a smartphone (12). This delay indicates the distance (6A, 6B, 6C, 6D) between the sound receiver and the sound transmitter (4) and is used to estimate the positioning and shape of the mosquito net (2).

Description

FIELD OF THE INVENTION

[0001] The present invention relates to a system for inspecting the proper placement of mosquito nets in human habitation spaces.

[0002] Mosquito nets remain the most effective method of protecting humans from malaria. In its simplest form, a mosquito net is a mesh fabric stretched over a space occupied by humans, such as a bed net. To improve effectiveness against mosquitoes, the prior art has disclosed a variety of insecticidal mosquito nets, the more effective of which contain insecticides that are transferred to mosquitoes when they come into contact with the net.

[0003] There have also been some attempts to incorporate electronic devices in conjunction with mosquito nets to improve protection against malaria mosquitoes.

[0004] In some cases, a warning system is incorporated to warn the user of mosquitoes that have entered the net. For example, Chinese patent applications CN106719589A and CN107495731A disclose mosquito nets equipped with detectors that detect the sounds of mosquitoes inside the net. When detected, a mosquito repellent sound is emitted to warn the user.

[0005] The proper use of bed nets is also discussed, particularly since users tend not to use them, while regular and sustained use is important for optimal protection.

[0006] An example is given in the article "Using motion detectors to estimate bed net use among residents in mosquito-infested areas of central Côte d'Ivoire: Preliminary results" by Koudou et al., published in 2014 in Parasites & Vectors 2014, 7:96 (doi:10.1186 / 1756-3305-7-96) http: / / www.parasitesandvectors.com / content / 7 / 1 / 96. The article describes a project in which small motion detectors were attached to bed nets to monitor movement during use. A PC was connected to the detectors on the bed nets and data was read from the logger. This article is also available online at: https: / / parasitesandvectors.biomedcentral.com / articles / 10.1186 / 1756-3305-7-96

[0007] Chinese utility model CN204029110U discloses a mosquito net with a pressure sensor that detects when a user touches the net to move away from it and issues an alarm to prevent mosquitoes from biting the user through the net. It also discloses the option of GSM communication to parents as a safety feature, especially when babies are in the net.

[0008] However, despite attempts in the art, there remains a need for improvements regarding the proper use of bed nets, particularly in areas with malaria.

[0009] It is therefore an object of the present invention to provide improvements in the art, in particular improved mosquito nets and improved methods for controlling the proper use of mosquito nets. This object and further advantages are achieved by a method and system for automatic, recursive surveillance of the proper placement of mosquito nets in human habitation spaces, as described below and in the claims.

[0010] That is, a mosquito net has multiple sound receivers attached to different parts of the net. A sound transmitter, such as a speaker, on the net emits a triggering reference sound, for example at ultrasonic frequencies, which is picked up by the various sound receivers and evaluated by an analysis system, including for example a smartphone, for the time delay of the sounds received by the various sound receivers. This delay indicates the distance between the sound transmitter and the sound receiver and is used to estimate the configuration of the mosquito net.

[0011] The systems and methods are described in further detail below.

[0012] For better understanding, here are some definitions:

[0013] The term "audio transmitter" is used below to refer to an electrical audio transducer that emits an audio signal as a result of receiving an electrical signal. Said audio signal may be an audible or inaudible signal. An example of the latter is an ultrasonic signal. The commonly used term for an audio transmitter is a speaker, but the more general term will be used herein to avoid confusion, especially in the case of inaudible signals.

[0014] The term "audio receiver" is used below to refer to an electrical audio transducer that receives an emitted audio signal and transmits a corresponding electrical signal. Optionally, said audio receiver is configured to receive sounds other than the audio signal emitted by said audio transmitter, for example to receive mosquito sounds to identify mosquitoes in or near a mosquito net. The usual term for audio receiver is microphone, but the more general term is used here to avoid confusion, especially in the case of inaudible sound signals.

[0015] Mosquito nets consist of a mesh fabric, which may or may not be treated with insecticide. Such nets, e.g., mosquito nets, are typically suspended from a support and extended over a human occupancy area, such as a sleeping area, to prevent mosquitoes from reaching humans or animals, such as pets, underneath the mesh fabric.

[0016] The present invention will now be described in more detail with reference to examples for the purposes of illustration and understanding.

[0017] An electric sound transmitter is installed on the net, which is usually attached to the net, but is adjacent to the net, for example attached to a string that secures the net, and which periodically emits a reference sound, which is advantageously inaudible so as not to disturb humans, and optionally is of ultrasonic frequency or at least partially ultrasonic frequency.

[0018] A number of electric sound receivers are provided at different locations in or on the mosquito net, in particular attached to or integrated into the mesh fabric. In some embodiments the sound receivers are attached to the mesh fabric, in other embodiments they are integrated into the weave. This depends on the size of the sound receiver. Currently sound transmitters and receivers are available that are a few millimeters in size, but it is expected that in the future they will become smaller in size so that they can be integrated into the fabric threads.

[0019] The sound receivers are placed at different distances relative to the sound transmitter when the mesh fabric is suspended and spread over the living space according to a predetermined preferred configuration of the mosquito net over the living space, and advantageously, the sound receivers are placed on the opposite side of the mosquito net relative to the living space over which the net is spread when correctly positioned.

[0020] The audio receiver is configured to receive a reference sound emitted by the audio transmitter and to provide an electrical or electronic receiver signal in response to the received sound.

[0021] The audio transmitter and receiver can be made using various technologies, one example being MEMS (Micro Electro Mechanical Systems) technology, which allows audio transmitters and receivers to be provided in millimeter sizes, yet with very low power consumption and high efficiency.

[0022] An analysis system is provided for analyzing the signals from the audio receivers to estimate the shape of the mosquitoes and, in particular, whether they are properly distributed in the living space. Specifically, the analysis system includes a computer operatively connected to the audio receivers and programmed to calculate and correlate the time delays between receiver signals to estimate the actual configuration of the mosquito net.

[0023] For example, the analysis system automatically estimates the actual configuration of the mosquito net by calculating and correlating the time delay between the emission time of the reference sound and the reception time of the corresponding receiver signal from the sound receivers, which time delay indicates the distance from one of the sound receivers to the sound emitter. This method means that the emission time in the analysis is related to the reception time, for example by measuring or inducing the emission time and using this in the calculation.

[0024] For completeness' sake, it is also possible to place a reference sound receiver closer to the reference sound generator than the remaining sound receivers and use the signal received from this reference sound receiver as a reference for calculating the time delay. Because this reference sound receiver is closer to the sound generator, this alternative corresponds to a known time offset from the actual emission time of the reference sound and can therefore be corrected with a known constant time offset for calculating the time delay from the sound generator to the other sound receivers. This method means that only the received signal is needed for this estimation.

[0025] In a practical embodiment, the computer is programmed to evaluate whether the time delay, or equivalent distance calculated based on the estimated sound propagation speed, corresponds to a value within a predetermined range of criteria for proper configuration of the net to protect the person inside it, or whether this value, if outside the predetermined range, indicates that the net is not properly positioned for protection or has been folded up for storage. In a later embodiment, artificial intelligence is used for such evaluation.

[0026] The system may also include a thermometer for measuring the temperature at the mosquito net location. The measured temperature can be used to measure the speed of sound propagation. Additionally or alternatively, the measured temperature can be used to determine whether a person or animal is present in the living space within the mosquito net. A humidity sensor can also be used to determine whether a person or animal is present within the mosquito net.

[0027] Advantageously, the system displays a warning to the user if the estimation indicates that the configuration of the net is not suitable.

[0028] For example, a smartphone may be programmed to warn the user if the estimation indicates that the mosquito net is not properly configured.

[0029] Optionally, the system is configured to transmit the receiver signal and / or the calculated time delay as a digital signal to a smartphone, either by wired connection or wirelessly (e.g. Bluetooth technology), advantageously together with the net's unique identification code. The smartphone is also convenient in that its location, and therefore the location of the net, can be used in association with said data. Optionally, geographical location data is received by GPS and linked to said data.

[0030] In some embodiments, the computer is implemented in a smartphone.

[0031] Cloud computing for predicting the configuration is also an option.

[0032] For example, the receiver signals and / or the calculated time delays are transmitted via the internet or other wireless data network, advantageously together with the net's unique identification code, to a remotely located server for analysis of the net's configuration. Optionally, a smart phone can be used for such transmission and communication, e.g., two-way communication with the server.

[0033] Collecting data in a server system has the advantage of being able to determine net use not only in individual situations, but also within households and communities.

[0034] The data from the audio receivers is optionally processed in real time, particularly with respect to time delays. However, the data can also be collected initially and then used for analysis. In particular, a complete data set from all receivers is useful for estimating the configuration of the mosquito net, so data (e.g., time-delayed data) is collected until at least one complete data set including data from all audio receivers is available.

[0035] In some practical embodiments, the analysis system includes a data collection routine, a calculation routine, and an evaluation routine. The term analysis system is used generically and includes the option of implementing all three routines in one unit, as well as the option of incorporating these routines in different units. Furthermore, these routines can be divided into different subroutines that are executed in different units. As will be explained below, various implementation methods are possible. The data collection routine is configured to collect signals from the audio receivers. For example, a controller or a smartphone collects data for the estimation. Pre-collection of data by electronic devices in the audio receivers is also an option. The calculation routine is configured to calculate a time delay between reception of reference sounds by the various audio receivers. The evaluation routine is configured to evaluate, based on an indication of the time delay, whether the mosquito net is hung and tensioned according to predetermined appropriate positioning criteria to protect humans therein, or whether the mosquito net is folded for storage.

[0036] In some embodiments, the analysis system comprises a controller attached to or implemented in the mosquito net, for example attached to or integrated into a mesh fabric, the controller being operatively connected to the audio emitter and audio receiver for transmitting signals for the assessment, and the controller is typically connected to the audio emitter and audio receiver by a cable, for example a cable integrated into or woven into the mesh fabric, although wireless communication between the controller and the audio emitter and audio receiver is possible.

[0037] For example, the controller includes a data collection routine and receives electrical or electronic signals from the audio receivers. Optionally, the controller stores the received signals in a database together with timestamps. The controller is configured to associate the timestamps with reference times for the emission of corresponding audio signals by the audio transmitters. For example, the reference times are measured by the controller transmitting a prompting signal to the audio transmitters to emit sounds. The time delay between the reference times and the timestamps when the emitted audio signals are received by the various corresponding audio receivers represents a measure of the actual distance between the audio transmitters and audio receivers.

[0038] Optionally, the controller also includes calculation routines and possibly evaluation routines to estimate whether the actual configuration of the net is suitable, although this need not be the case as the controller collects the data and the calculation and evaluation routines are executed on another device, such as a smartphone or cloud computer, as already mentioned above, as will be explained below.

[0039] For example, digital data relating to the received sounds may be transmitted from the controller to another computer (optionally a smartphone) and from there via the Internet or other wireless data network to a central server located remotely from the mosquito net for analysis of the positioning of the mosquito net.

[0040] Optionally, this separate computer, e.g. a smartphone, rather than the controller, contains the evaluation routine implemented as a computer routine. In the case of a smartphone, such a computer routine is implemented as an application, also known in modern terms as an APP. This computer routine, in particular the smartphone APP, is programmed to functionally connect to a central server located remotely from the mosquito net, to digitally communicate with this central server and to evaluate the configuration of the mosquito net according to this central server. Advantageously, in the case of a smartphone, the APP is programmed to allow the user to interact with the smartphone and to display information about the evaluated positioning of the mosquito net to the user, including a warning if the evaluation indicates that the positioning of the mosquito net is inappropriate.

[0041] The object of the present invention is also achieved by the following method, in which a mosquito net is provided, comprising a mesh fabric, the mosquito net being adapted to be suspended from a support and extended into a space occupied by humans to prevent mosquitoes from reaching humans underneath the mesh fabric. An audio transmitter disposed on the net periodically emits a reference sound. The emitted reference sound is received by a plurality of audio receivers disposed in or on the mosquito net at different positions and positioned such that the audio receivers are at different distances from the audio transmitter when the mesh fabric is suspended and extended into the space occupied by humans. The received reference sound signals are transmitted from the audio receivers to an analysis system, which uses a computer to estimate the actual configuration of the mosquito net by calculating and correlating the time delays between the received signals.

[0042] In particular, the analysis system calculates the time delay between the reception of reference sounds by the various audio receivers and, based on an indication of this time delay, can assess whether the mosquito net is hung and tensioned according to predetermined proper positioning criteria to protect the persons therein or whether the mosquito net is folded up for storage.

[0043] The speed of sound depends on the air density and therefore on the ambient temperature. To improve accuracy, a thermometer is optionally integrated into the system (e.g., controller).

[0044] In some embodiments, the audio receiver and / or the controller are configured for audio filtering of the received audio signal to filter the signal from ambient noise. If the reference sound emitted from the audio transmitter is in the ultrasonic frequency range, the audio receiver may advantageously be configured to receive only ultrasonic signals.

[0045] Optionally, the audio receivers are designed to also receive and possibly record sounds made by mosquitoes. By analyzing the delay in receiving this audio by the various audio receivers, the location of the mosquito can be determined and, for example, if a mosquito is determined to be inside the mosquito net, a warning signal can be sent to the user from the controller or smartphone. For example, the audio transmitter can be used to send a warning to the user.

[0046] Data collected from mosquito detection within the nets can also be used, for example, in correlation with measurements of net configuration in the server system to generate statistics on proper use of the nets, the latter being useful for providing targeted malaria information to users to ensure better protection.

[0047] For power supply, the audio receiver, audio transmitter and optional controller may be connected to a rechargeable battery or at least periodically to a charging unit, optionally connected to a grid power source or a solar cell, or the battery may be charged with power from a mobile phone, which then transfers power to the rechargeable battery of the mosquito net system.

[0048] To minimize power consumption, the electronics, audio receiver, and / or audio transmitter may be programmed to enter a sleep mode from which they automatically wake up periodically. Optionally, a smartphone is used to wake the electronics from sleep mode. Low power consumption allows the system to use a relatively small battery, which prevents the electronics from adding bulk to the net.

[0049] As noted, mosquito nets play an important role in combating malaria in rural areas. While many remote villages and rural areas in Africa may have a low level of general infrastructure, mobile phone systems are usually well developed, and the proportion of mobile phone users, including smartphones, among the local population is relatively high. This means that the above-mentioned mosquito nets are suitable for rural areas, for example, in Africa, regardless of the fact that they require internet access and battery charging. In line with the widespread use of mobile phones in these villages, mobile phone charging stations are also provided, for example, in community centers. However, once the mobile phones are charged in such centers, the batteries in the mosquito net system can be recharged using the appropriate cables and software.

[0050] Additionally, the system is particularly useful in clinics and hospitals where patient protection is of paramount importance. [Brief explanation of the drawings]

[0051] The invention will now be explained in more detail with reference to the drawings. Figure 1 shows the principle of a mosquito net equipped with a positioning detection system. Figure 2 shows the results of a test on the feasibility of timing for measuring distance.

[0052] Figure 1 shows a system (1) that includes a mosquito net (2) suspended above a sleeping area (3). The mosquito net (2) is fitted with a micro-sound transmitter (4) that emits a specific reference sound according to a predetermined pattern. A number of sound receivers (5A, 5B, 5C, 5D) are attached to various locations on the mosquito net (2).

[0053] When the sound transmitter (4) emits a sound, the sound receivers (5A, 5B, 5C, 5D) pick up the sound and transmit a corresponding electrical or electronic signal to the controller (8) on the mosquito net (2) for further analysis. Depending on the linear distance (6A, 6B, 6C, 6D) from the sound receivers (5A, 5B, 5C, 5D) to the sound transmitter (4), the sound signal from the sound transmitter (4) to each sound receiver (5A, 5B, 5C, 5D) will arrive slower or faster at the respective sound receiver (5A, 5B, 5C, 5D). Therefore, the propagation time is related to the linear distance (6A, 6B, 6C, 6D) from the sound receiver (5A, 5B, 5C, 5D) to the sound transmitter (4). Since the audio receivers (5A, 5B, 5C, 5D) are located at various locations on the mosquito net (2), particularly on opposite sides of the sleeping area (3) and on both sides closer and farther from the audio transmitter (4), comparing the propagation times from the audio transmitter (4) to the various audio receivers (5A, 5B, 5C, 5D) reveals information about the actual current configuration of the mosquito net. In particular, if the actual positions of the audio receivers (5A, 5B, 5C, 5D) at the time of measurement are closer to the audio transmitter (4) than to other positions, audio analysis will reveal whether the mosquito net (2) is folded or properly spread out over the sleeping area (3). Furthermore, analysis of the time delays of the signals from the receivers (5A, 5B, 5C, 5D) will reveal whether the mosquito net (2) is being pulled to one side or the other, folding one side to 9A or the other to 9B, or whether the mosquito net (2) is being rolled up over the sleeping area (3).

[0054] For example, the time delay between when the sound from the sound transmitter is received by each sound receiver (5A, 5B, 5C, 5D) may be compared to empirical data stored in the memory of the controller (8). As will be explained in more detail below, experiments have shown that a simple setup using a very small sound receiver and a miniature sound transmitter can measure the relative distance between the sound transmitter and sound receiver to within about one meter, and the spacing between the sound receivers to less than 2 cm.

[0055] If an inaudible signal (eg ultrasound) is used, this sound will not disturb a person sleeping under the mosquito net.

[0056] Repeated measurements stored in the memory of the controller (8) reveal not only whether the mosquito net (2) is being used properly and regularly, but also whether the bedding (3) under the mosquito net (2) is being used correctly to provide adequate protection from mosquitoes. This assessment may be performed using artificial intelligence.

[0057] For power supply, the audio receivers (5A, 5B, 5C, 5D) and audio transmitter (4) as well as the controller (8) may each be equipped with a rechargeable battery connected by a cable to a charging unit (10) and attached to the mosquito net (2) or separately. The cable may be thin and flexible and integrated into the fabric material of the mosquito net, for example woven into it.

[0058] Alternatively, the audio receivers (5A, 5B, 5C, 5D) and the audio transmitter (4) are connected by cables to a common rechargeable battery (14) that is charged by the charging unit (10). Optionally, the battery (14) is integrated into the charging unit (10) as illustrated in the figures. Alternatively, the battery (14) is integrated into the controller (8). There are other battery placement options as well.

[0059] The charging unit 10 is optionally connected to a grid power source 15 or a solar cell by a cable 11. Optionally, the charging unit 10 can also be used to charge the mobile phone 12. Alternatively, the battery 14 can be charged by transferring power from the mobile phone 12 to the rechargeable battery 14, thus eliminating the need for the charging unit 10 and cable 11. There are various options.

[0060] As pointed out, the audio receivers (5A, 5B, 5C, 5D) and the audio transmitter (4) are very small and consume very little power, so the battery (14) lasts a long time and does not need to be charged frequently. In particular, if the audio receivers transmit and receive audio periodically, for example, once every 30 minutes, the power consumption is small.

[0061] The electronics of the controller 10, audio receivers (5A, 5B, 5C, 5D) and audio transmitter (4) can be programmed to go into a sleep mode where they automatically wake up periodically, minimizing power consumption. Low power consumption means that a relatively small battery can be used for the system, preventing the electronics from adding bulk to the mosquito net (2).

[0062] There are several options for transmitting and analyzing the electrical or electronic signals (e.g., digital signals). For example, the controller (8) can be provided as a small microcomputer chip attached to the mosquito net (2) or integrated into the mesh fabric of the mosquito net (2). For example, it triggers the emission of an audio signal from the audio transmitter (4) and receives corresponding signals from the audio receivers (5A, 5B, 5C, 5D). It communicates with the audio transmitter (4) and the audio receivers (5A, 5B, 5C, 5D) via cables integrated into the mesh fabric of the mosquito net (2), although wireless communication is also possible in principle. Once the signals from the audio receivers (5A, 5B, 5C, 5D) are received by the controller (8), they can be analyzed there.

[0063] Alternatively, the signals received by the controller (8) along with their timestamps can be sent to a separate analysis computer, where they are analyzed for signal time delays between the audio receivers. For example, the digital version of the received audio signal and its timestamp can be wirelessly transmitted to a smartphone (12), which can then be used as the analysis computer by an activated computer application (also called an APP in modern terms) stored on the smartphone (12). The advantage of the latter is that the smartphone (12) is regularly charged by the user and has high computing power. Therefore, data analysis can be performed without using power from the rechargeable battery used to power the audio receivers (5A, 5B, 5C, 5D) and audio transmitter (4) or without using power for data transmission.

[0064] Optionally, for example, once data analysis is completed, the data is transferred to a central server (16) for collection and analysis. A smartphone (12) connected to the internet (13) can be used for this purpose, for example after analyzing the data in the controller (8) on the mosquito net or by an APP in the smartphone (12).

[0065] Alternatively, the data, together with their timestamps, are received by the smartphone (12) from the controller (8) on the mosquito net (2), without being analyzed by the controller (8) on the mosquito net (2) or in the smartphone (12), but are simply received from the controller (8) with the corresponding timestamps and stored in the data buffer of the controller (8) on the mosquito net (2) or in the smartphone (12), before being transferred to the central server (16) for collection and further analysis. In this case, the controller (8) on the mosquito net (2) is not used to analyze the recorded data, but is used to trigger the audio transmitter (4), collect the recorded signals in a buffer with the correct timestamps, and transmit (18) them to the central server (16) via a wireless connection 17 (e.g., Internet (13)) using the smartphone (12) simply as a transceiver, possibly also as a data collection buffer, with the final analysis then being carried out by the central server (16).

[0066] Optionally, the evaluation results are transmitted to a smartphone (12) to alert the user if the evaluation reveals that the actual configuration of the mosquito net does not match predetermined criteria for proper configuration.

[0067] Further optionally, if analysis by the controller (8) on the mosquito net (2) or the smartphone (12) reveals that the mosquito net (2) is not properly installed, the smartphone (12) may be programmed to provide a feedback signal (such as a warning) to the user.

[0068] With modern MEMS technology, the sound transmitter (4) and sound receivers (5A, 5B, 5C, 5D) used in e.g. hearing aids are about 1 mm in size and therefore small and lightweight, smaller than the size of a mosquito in comparison.

[0069] With reference to Figure 2, the feasibility of a technique was investigated in which two audio receivers (Mic 1 and Mic 2) were placed at different distances from a micro-speaker (Speaker MEMS). The first audio receiver was placed 30 cm from the audio transmitter, and the second audio receiver was placed 130 cm from the audio transmitter. This linear configuration is shown in Figure 2A.

[0070] In this experiment, the audio transmitter emitted a 250-millisecond-long linear chirp between 16 and 22 kHz. The audio receivers (Mic 1 and Mic 2) recorded audio sampled at 48 kHz. A computer program analyzed this signal and applied conventional time-delay estimation techniques to correlate the delayed signal with distance.

[0071] Figure 2B shows the reception of a signal by a first audio receiver (Mic 1) when the time delay estimate is converted to distance based on the known speed of audio propagation. Similarly, Figure 2C shows the distance from the audio transmitter to a second audio receiver (Mic 2) when the time delay is converted to distance. Figure 2D shows the distance between these audio receivers.

[0072] As can be seen from the diagram in Figure 2, the distance can be estimated to an accuracy of less than 2 cm, i.e., an accuracy of 18 mm. The actual distance from the sound transmitter to the sound receiver and the distance between these sound receivers were accurately estimated. The analysis system used the time delay between the sound transmission by the sound transmitter and the reception of the sound signal by the sound receiver to calculate the distance from the sound transmitter to the sound receiver.

[0073] As noted, the air temperature around the mosquito net affects the speed of sound propagation. To improve positioning, the temperature of the environment may also be measured. For example, the controller (8) may be equipped with or connected to a small thermometer to improve the accuracy of the measurement.

[0074] The described methods and systems are useful for a new generation of mosquito nets that combine the latest lightweight electronic communication technology with the simple and safe protection of a well-known mesh fabric, ensuring proper use and thereby increased protection against malaria.

Claims

1. A system (1) for automated and repeated inspection of the proper placement of mosquito nets (2) in human habitation spaces (3), comprising: - a mosquito net (2) suspended from a support and extending into the human habitation space (3) and including a mesh fabric configured to prevent mosquitoes from reaching humans underneath; - an electric sound transmitter (4) arranged in said mosquito net (2) and configured to emit a reference sound repeatedly at the emission time; - a plurality of electric sound receivers (5A, 5B, 5C, 5D) provided in or on the mosquito net (2) at different positions, and arranged to have different distances (6A, 6B, 6C, 6D) from the sound transmitter (4) when the mesh fabric is suspended and spread over the living space (3) according to a predetermined preferred configuration of the mosquito net (2) over the living space (3), and configured to receive a reference sound emitted from the sound transmitter (4) and to provide an electric receiver signal in response to the received sound; - an analysis system comprising a computer (8, 12) operatively connected to said audio receivers (5A, 5B, 5C, 5D) and programmed to estimate the actual configuration of said mosquito net (2) by calculating and correlating the time delays between said receiver signals; Including, the system.

2. 2. The system of claim 1, wherein the computer (8, 12) is programmed to estimate the actual configuration of the mosquito net (2) by calculating and correlating the time delay between the emission time of the reference sound and the reception time of the corresponding receiver signal from the sound receivers (5A, 5B, 5C, 5D), the time delay indicating the distance from one of the sound receivers (5A, 5B, 5C, 5D) to the sound transmitter (4).

3. 10. A system according to any one of the preceding claims, wherein the system is configured to show a warning to the user if the estimation indicates that the configuration of the mosquito net (2) is not suitable.

4. 10. The system according to any one of the preceding claims, wherein the system is configured for transmitting (18) the receiver signal and / or the calculated time delay as a digital signal to a smartphone via wired or wireless connection together with a unique identification code of the mosquito net.

5. 10. The system of claim 1, wherein the computer is implemented in a smartphone.

6. 6. The system of claim 5, wherein the smartphone is programmed to show a warning to the user if the estimation indicates that the configuration of the mosquito net (2) is not appropriate.

7. 10. The system according to any one of the preceding claims, wherein the system is configured for transmitting (18) the receiver signals and / or the calculated time delays together with the unique identification code of the mosquito net (2) via the Internet (13) or other wireless data network to a central server (16) located remotely from the mosquito net (2) in order to analyze the configuration of the mosquito net (2).

8. 10. A system according to any one of the preceding claims, wherein at least one of the audio transmitter (4) and the audio receiver (5A, 5B, 5C, 5D) is based on MEMS technology.

9. 10. A system according to any one of the preceding claims, wherein the reference sound of the sound transmitter (4) is at least partly an inaudible sound, for example an ultrasonic sound.

10. 10. A system as claimed in any one of the preceding claims, wherein the system is configured to receive sounds other than the reference sound emitted via the sound receiver, and to evaluate sounds from mosquitoes received by the sound receiver as an indication that a mosquito is present within the mosquito net, and if so, to display a warning to a user.

11. 10. A method of using a system according to any one of the preceding claims for automatic and repeated investigation of the correct placement of mosquito nets (2) in human habitation spaces (3), comprising: - providing a mosquito net (2) comprising a mesh fabric adapted to be suspended from a support and extended into a human occupancy space (3) and to prevent mosquitoes from reaching humans underneath the mesh fabric; - repeatedly emitting a reference sound from an electric sound generator (4) placed on the mosquito net (2); - receiving the reference sound emitted by a plurality of electric sound receivers (5A, 5B, 5C, 5D) arranged in or on the mosquito net (2) at different positions and configured to be installed at different distances (6A, 6B, 6C, 6D) from the sound transmitter (4) when the mesh fabric is suspended and spread over the living space (3) according to a predetermined preferred configuration of the mosquito net (2) over the living space (3), and providing an electric receiver signal in any of the sound receivers (5A, 5B, 5C, 5D) in response to the received sound; - estimating the actual configuration of the mosquito net (2) by calculating and correlating the time delays between the receiver signals with a computer (8, 12) as part of an analysis system functionally connected to the audio receivers (5A, 5B, 5C, 5D). A method comprising:

12. 12. The method of claim 11, wherein the method comprises automatically estimating the actual configuration of the mosquito net (2) by computing and correlating the time delay between the emission time of the reference sound and the reception time of the corresponding receiver signal from the sound receivers (5A, 5B, 5C, 5D), wherein any of the time delays indicates the distance from one of the sound receivers (5A, 5B, 5C, 5D) to the sound transmitter (4).

13. 13. The method according to claim 12, wherein the method comprises the computer evaluating whether the time delay, or the equivalent distance calculated based on the estimated sound propagation speed, corresponds to a value within a predetermined range of criteria for proper configuration of the mosquito net (2) to protect the person inside the mosquito net (2), or if this value is outside the predetermined range, indicating that the mosquito net (2) is not properly installed for protection or is folded up for storage, and displaying a warning to the user if the estimation indicates that the mosquito net (2) is not properly configured.

14. 14. The method according to claim 13, wherein the method comprises transmitting (18) the receiver signal and / or the calculated time delay as a digital signal to a wired or wireless smartphone programmed to interact with a user and to warn the user if the estimation indicates that the configuration of the mosquito net (2) is not suitable.

15. 15. The method of any one of claims 11 to 14, wherein the method comprises measuring the temperature and / or humidity in the mosquito net, transmitting the measurements to the analysis system to determine whether a person is present inside the mosquito net, and linking the measurements to the time-delayed data.

16. 16. The method according to any one of claims 11 to 15, wherein the method comprises transmitting (18) the receiver signals and / or the calculated time delays together with the unique identification code of the mosquito net (2) via the Internet (13) or other wireless data network to a central server (16) located remotely from the mosquito net (2) in order to analyze the configuration of the mosquito net (2).

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