Description:FIELD OF THE INVENTION

[0001] The present disclosure generally relates to the field of information processing systems and methods in vehicles and accessories. More particularly, the present disclosure relates to a system and a method for wear detection of a helmet when the helmet is worn by a user.

BACKGROUND

[0002] Helmet is a very common protective gear worn to protect the head of a user. A helmet can be used by the user in construction sites, mines, the armed forces, and similar such applications. It is also necessary to wear helmets while riding a horse or driving any saddle type vehicle such as a scooter, a motorcycle, or a bicycle. Several helmets are available today for various safety purposes such as detecting a fall of the user, detecting potholes, collecting air quality data on roads and wear detection, when the helmet is worn by the user.
[0003] The state of the art helmets need to be operated manually by the user to turn on the helmet and its functions. Furthermore, in the state of the art, the helmet includes sensors (for example, IR sensors only) for wear detection. These helmets with IR sensors may provide false triggers for wear detection. The false triggers for wear detection may be due to an obstruction caused by the objects such as scarf, hair of the user, for example other than head and provide inaccurate results.
[0004] As a result, such helmets are not very efficient and reliable. The solution other than use of sensors for wear detection when the helmet is worn by the user include implementation of the piezoelectric, pyroelectric, and other transducers which create a hindrance and also cause discomfort to the user.

[0005] Therefore, in view of the above-mentioned problems, it is advantageous to provide a system and a method that can overcome one or more of the problems and limitations of existing helmets mentioned above.

SUMMARY

[0006] This summary is provided to introduce a selection of concepts, in a simplified format, that are further described in the detailed description of the invention. This summary is neither intended to identify key or essential inventive concepts of the invention nor is it intended for determining the scope of the invention.
[0007] To overcome or at least mitigate one of the problems mentioned above in the state of the art helmets, a helmet is needed that is configured for automatic wear detection, when the helmet is worn by a user. It is to be noted that in some embodiments disclosed herein, wear detection may mean detecting that the helmet is worn by the user and at least turning on an electronic unit inside the helmet when the helmet is worn by the user.
[0008] In an embodiment of the present disclosure, a system for wear detection of a helmet when the helmet is worn by a user, is disclosed. The system includes an infrared module having at least one infrared transmitter and at least one infrared receiver positioned separately on the inner surface of the helmet. The infrared module is configured for sensing an obstruction to the infrared radiation from the at least one infrared transmitter to the at least one infrared receiver for obtaining a first data. The system includes an inertial measurement unit, positioned inside the helmet, configured for detecting an orientation of the helmet, within predefined limits for the orientation, for obtaining a second data. The system includes a processing module configured for receiving and processing the first data and the second data for detecting a wear state of the helmet when each of the first data and the second data satisfy respective predefined conditions.
[0009] In another aspect of the present disclosure, a method for wear detection of a helmet, when the helmet is worn by a user, is disclosed. The method includes sensing, within the helmet, an obstruction to an infrared radiation emitted by at least one infrared transmitter toward at least one infrared receiver of an infrared module, for obtaining a first data. The method includes detecting an orientation of the helmet within predefined limits, for the orientation of the helmet, using an inertial measurement unit for obtaining a second data. The method also includes receiving and processing the first data and the second data for detecting a wear state of the helmet when each of the first data and the second data satisfy respective predefined conditions.
[0010] In yet another aspect of the present disclosure, a helmet for wear detection, when worn by a user, is disclosed. The helmet includes an infrared module comprising at least one infrared transmitter and at least one infrared receiver positioned separately on the inner surface of the helmet. The at least one infrared transmitter is positioned on a first inner side of the helmet and the at least one infrared receiver is positioned on a second inner side of the helmet such that the at least one infrared receiver is capable of sensing the infrared radiation radiated by the at least one infrared transmitter, in the absence of an obstruction between the at least one infrared receiver and the at least one infrared transmitter. The helmet includes an inertial measurement unit, positioned inside the helmet, comprising one or more accelerometers and at least one gyroscope. The system includes a processing module communicatively coupled to the infrared module and the inertial measurement unit.
[0011] The present disclosure provides a configuration of a system along with a method to operate the system for wear detection of a helmet when the helmet is worn by a user.
[0012] To further clarify the advantages and features of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof, which are illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. The invention will be described and explained with additional specificity and detail with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS

[0013] These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
[0014] Figure 1 illustrates a block diagram of a system configured for wear detection of a helmet when the helmet is worn by a user, according to an embodiment of the present disclosure;
[0015] Figure 2 illustrates a block diagram of a processing module of the system of Figure 1, according to an embodiment of the present disclosure;
[0016] Figure 3 is a diagram showing a wear detection module and its sub-systems for wear detection when the helmet is worn by the user, according to an embodiment of the present disclosure;
[0017] Figure 4A illustrate a schematic of an infrared sensor system known in the state of the art;
[0018] Figures 4B illustrate a schematic of an infrared sensor sub-system placed on left-hand side of a printed circuit board respectively, according to an embodiment of the present disclosure;
[0019] Figure 4C illustrate a schematic of an infrared sensor sub-system placed on right-hand side of the printed circuit board respectively, according to an embodiment of the present disclosure;
[0020] Figure 5A and 5B illustrate a placement of the IR transmitter and IR receiver on the inner surface of the helmet, according to an embodiment of the present disclosure;
[0021] Figure 6A illustrates a block diagram of an inertial measurement unit sub-system configured for providing an orientation of the helmet, according to an embodiment of the present disclosure;
[0022] Figure 6B illustrates a placement of the inertial measurement unit sub-system on the inner side of the helmet, according to an embodiment of the present disclosure;
[0023] Figure 7 illustrates a microcontroller sub-system and its interface with the system of Figure 1, according to an embodiment of the present disclosure;
[0024] Figure 8 is a flow diagram for a wear detection method, according to an embodiment of the present disclosure;
[0025] Figure 9A and 9B illustrates a flow chart depicting a method for wear detection (Helmet ON) and wear removal (Helmet OFF) respectively, according to an embodiment of the present disclosure; and
[0026] Figure 10 illustrates a truth table showing output of the method for wear detection (Helmet ON) and wear removal (Helmet OFF) respectively, according to an embodiment of the present disclosure.
[0027] Further, skilled artisans will appreciate that elements in the drawings are illustrated for simplicity and may not have necessarily been drawn to scale. For example, the flow charts illustrate the method in terms of the most prominent steps involved to help to improve understanding of aspects of the present invention. Furthermore, in terms of the construction of the device, one or more components of the device may have been represented in the drawings by conventional symbols, and the drawings may show only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the drawings with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.

DETAILED DESCRIPTION OF FIGURES

[0028] For the purpose of promoting an understanding of the principles of the present disclosure, reference will now be made to the various embodiments and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the present disclosure is thereby intended, such alterations and further modifications in the illustrated system, and such further applications of the principles of the present disclosure as illustrated therein being contemplated as would normally occur to one skilled in the art to which the present disclosure relates.
[0029] It will be understood by those skilled in the art that the foregoing general description and the following detailed description are explanatory of the present disclosure and are not intended to be restrictive thereof.
[0030] Whether or not a certain feature or element was limited to being used only once, it may still be referred to as “one or more features” or “one or more elements” or “at least one feature” or “at least one element.” Furthermore, the use of the terms “one or more” or “at least one” feature or element do not preclude there being none of that feature or element, unless otherwise specified by limiting language including, but not limited to, “there needs to be one or more…” or “one or more elements is required.”
[0031] Reference is made herein to some “embodiments.” It should be understood that an embodiment is an example of a possible implementation of any features and/or elements of the present disclosure. Some embodiments have been described for the purpose of explaining one or more of the potential ways in which the specific features and/or elements of the proposed disclosure fulfil the requirements of uniqueness, utility, and non-obviousness.
[0032] Use of the phrases and/or terms including, but not limited to, “a first embodiment,” “a further embodiment,” “an alternate embodiment,” “one embodiment,” “an embodiment,” “multiple embodiments,” “some embodiments,” “other embodiments,” “further embodiment”, “furthermore embodiment”, “additional embodiment” or other variants thereof do not necessarily refer to the same embodiments. Unless otherwise specified, one or more particular features and/or elements described in connection with one or more embodiments may be found in one embodiment, or may be found in more than one embodiment, or may be found in all embodiments, or may be found in no embodiments. Although one or more features and/or elements may be described herein in the context of only a single embodiment, or in the context of more than one embodiment, or in the context of all embodiments, the features and/or elements may instead be provided separately or in any appropriate combination or not at all. Conversely, any features and/or elements described in the context of separate embodiments may alternatively be realized as existing together in the context of a single embodiment.
[0033] Any particular and all details set forth herein are used in the context of some embodiments and therefore should not necessarily be taken as limiting factors to the proposed disclosure.
[0034] The terms “comprises”, “comprising”, or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process or method that comprises a list of steps does not include only those steps but may include other steps not expressly listed or inherent to such process or method. Similarly, one or more devices or sub-systems or elements or structures or components proceeded by “comprises... a” does not, without more constraints, preclude the existence of other devices or other sub-systems or other elements or other structures or other components or additional devices or additional sub-systems or additional elements or additional structures or additional components.
[0035] Embodiments of the present disclosure will be described below in detail with reference to the accompanying drawings.
[0036] For the sake of clarity, the first digit of a reference numeral of each component of the present disclosure is indicative of the Figure number, in which the corresponding component is shown. For example, reference numerals starting with digit “1” are shown at least in Figure 1. Similarly, reference numerals starting with digit “2” are shown at least in Figure 2.
[0037] In some embodiments, the term ‘turning on the helmet automatically’ may be referred to as ‘turn-on’ or ‘turning on’ and ‘turned-on’ and may reflect the same meaning and may be used interchangeably in the description and figures. In some embodiments, the term ‘turning the helmet off, automatically’ may be referred to as ‘turn-off’ or ‘turning off’ and ‘turned-off’ and may reflect the same meaning and may be used interchangeably in the description and figures. The term ‘turning on the helmet automatically’ may mean at least turning on an electronic unit inside the helmet when the helmet is worn by the user and the electronic unit is turned on to perform one or more functions upon wear detection of the helmet by the user. Similarly, the term ‘turning the helmet off automatically’ may mean at least turning off an electronic unit inside the helmet when the helmet is taken off (removed) by the user and the electronic unit is turned off from performing one or more functions upon taking the helmet off by the user.
[0038] It is to be noted that the term ‘first data’ may be referred to as ‘infrared data’ or ‘infrared receiver output data’, ‘IR Rx data’ or ‘IR Rx output data’ and may reflect the same meaning and may be used interchangeably in the description and figures. It is to be noted that the term ‘second data’ may be referred to as ‘or ‘inertial measurement unit data’, or ‘IMU data’ and may reflect the same meaning and may be used interchangeably in the description and figures.
[0039] Figure 1 illustrates a block diagram of a system 100 configured for wear detection of a helmet when the helmet is worn by the user, according to an embodiment of the present disclosure. In an embodiment, the system 100 may include, but is not limited to, an infrared module 102, an inertial measurement unit 104, a processing module 105 issuing a wear detection output 115, details of which will be given in the subsequent paragraphs.
[0040] As mentioned above, the system 100 is configured for wear detection of the helmet when the helmet is worn by the user. The system 100 provides an automated wear detection output 115, when the helmet is worn by the user. The wear detection output 115 of the system 100 is used for at least turning on an electronic unit inside the helmet when the helmet is worn by the user and turning the helmet off when the user takes the helmet off.
[0041] Referring to Figure 1, the system 100 includes the infrared module 102. The infrared module 102 includes at least one infrared transmitter and at least one infrared receiver positioned separately. The term ‘separately’ used herein refers to the infrared transmitter being on a first inner surface of the helmet and the infrared receiver being on a second inner surface of the helmet such that the infrared radiation from the transmitter may be received by the receiver in the absence of any obstructions between the two.
[0042] It is to be noted that the term ‘at least one infrared transmitter’ may be referred to as ‘infrared transmitter’ or ‘IR transmitter’ or ‘IR Tx’ and may reflect the same meaning and may be used interchangeably in the description and figures. Similarly, the term ‘at least one infrared receiver’ may be referred to as ‘infrared receiver’ or ‘IR receiver’ or ‘IR Rx’ and may reflect the same meaning and may be used interchangeably in the description and figures.
[0043] The infrared module 102 is configured for sensing an obstruction to the infrared radiation from the at least one infrared transmitter to the at least one infrared receiver, for obtaining a first data. The details with respect to the working of the infrared module 102 and its components, schematic of the infrared sensor sub-system of the infrared module 102, position and placement of the infrared sensor sub-system of the infrared module 102 in the helmet are explained in detail further with reference to Figure 4B, 4C, 5A, and 5B.
[0044] The system 100 includes the inertial measurement unit 104. The inertial measurement unit 104 is positioned inside the helmet and is configured for detecting an orientation of the helmet, within predefined limits for the orientation, for obtaining a second data. The second data is obtained by combining motion of the helmet sensed by an accelerometer of the inertial measurement unit 104 and a gyroscope sensing the orientation of the helmet having three Euler angles within predefined ranges for each of them. As known in the state of art, Euler angles are successive planar rotation angles around x, y, and z axes. The details with respect to working of the inertial measurement unit 104, sensors used in the inertial measurement unit 104, the position and placement of the sub-system of the inertial measurement unit 104 in the helmet is explained in detail further with reference to Figure 6A and 6B.
[0045] The system 100 includes the processing module 105 configured for receiving and processing the first data and the second data for detecting a wear state of the helmet when each of the first data and the second data satisfy respective predefined conditions. The predefined conditions comprise: (a) the first data indicating, for a predefined duration; and (b) the second data indicating that the helmet is oriented within predefined limits for each of the Euler angles and is also not static but experiencing motion.
[0046] In one example, when the user wears the helmet, the output from the IR Rx becomes High (say Logic state 1). Whenever the user takes the helmet off then the output from the IR Rx becomes Low (say Logic 0). Hence, it is observed that, when there is no object or obstruction in between the IR Tx and IR Rx, then the IR Rx output is driven to Logic 0 and if any object or obstruction is present in between the IR Tx and IR Rx, then the IR Rx output is driven to Logic 1.
[0047] One of the predefined conditions for detecting the state of the helmet having been worn by the user is the first data indicating, for a predefined duration. For example, if any object or obstruction is present in between the IR Tx and IR Rx, then the IR Rx output should be driven to Logic 1 for a predefined duration. In one example, the predefined duration may include a duration of up to 3 seconds to up to 7 seconds and is based on debounce phenomenon.
[0048] The second predefined condition includes, the second data indicating that the helmet is oriented within predefined limits for each of the three Euler angles and is experiencing motion. For example, a wear detection logic in the processing module 105 is configured for processing the second data for calculating a rotational angle of the helmet. The rotational angle is used to derive (which will be described in detail hereinafter with reference to Figure 6A) whether the helmet is oriented in a wear position or not.
[0049] The wear detection output 115 of the system 100 as disclosed herein provides convenience to the user. Due to automatic wear detection of the helmet, the user does not need to manually turn-on the helmet by pressing a power button, for example. When the user wears the helmet, the wear detection logic in the processing module 105 is configured to turn-on the helmet automatically and turn-off the helmet when the user takes the helmet off. Sometimes, the users may forget to turn off the helmet even after the removal which leads to the consumption by the helmet in this state. This drawback is eliminated by using the wear detection logic of the disclosed system 100 by turning the helmet off when the user takes the helmet off.
[0050] In another example scenario with a state of the art helmet is when the user has placed gloves inside the helmet, a very common practice, and the wear detection logic is configured to use only the infrared module output (without the inertial measurement unit 104 as disclosed in this disclosure). Then the helmet will be turned. This is not correct since the user is not actually wearing the helmet. Further, we may consider another example scenario, with a helmet configured for sensing reflected IR radiation (as shown in Figure 4), reflected from the face or head of the user, where the user has a beard or long hair, and the hair might absorb the infrared radiation and not reflect sufficient IR radiation for detection. Then such a wear detection module may fail to detect that the user has in fact worn the helmet not providing a wear detection trigger.
[0051] To avoid this limitation mentioned in the above-described examples, the system 100 as disclosed herein uses a combination of the first data obtained from the infrared module 102 and the second data obtained from the inertial measurement unit 104 which gives accurate results. The combination of the first data obtained from the infrared module 102 and the second data obtained from the inertial measurement unit 104 are processed by the wear detection module. The wear detection module, which implements the sensor fusion technique for combining the data obtained from the IMU subsystem as the sub-component of the system 100, is configured for the detecting orientation of the helmet.
[0052] Thus, using the first data and the second data, the wear detection module of the processing module 105 provides the output 115 to decide whether the helmet is worn by the user or the helmet is not worn by the user. The details with respect to working of the wear detection logic of the wear detection module present in the processing module 105 is explained in detail below in Figure 3.
[0053] A manner in which the wear detection module in the processing module 105 of the system 100 is configured for wear detection of the helmet when the helmet is worn by the user is described in further detail below.
[0054] Figure 2 illustrates a block diagram of a processing module 205 of the system 100 of Figure 1, according to an embodiment of the present disclosure. In an embodiment, the processing module 205 may include, but is not limited to, a microcontroller 220 that includes a sensor fusion module 206, a wear detection module 225 comprising a wear detection logic 210 producing a wear detection output 215, details of which will be explained in subsequent paragraphs. The reference numeral 202A represents data read and obtained by the infrared module 102, the reference numeral 204A represents data read and obtained by the inertial measurement unit 104.
[0055] The wear detection logic 210 is configured to read the infrared receiver output data 202A and the inertial measurement unit data 204A. The inertial measurement unit data 204A i.e., accelerometer and gyroscope data are given as input to the sensor fusion module 206. This sensor fusion module 206 may be the sub-component of the wear detection module 225 which is used for the calculation of the orientation of the helmet. The output of the sensor fusion module 206 and the infrared receiver 204 is given as an input to the wear detection logic 210 in the wear detection module 225.
[0056] For example, if the user wears the helmet, then the output from the wear detection module 225 is logic high i.e., a 1 which indicates that the user has worn the helmet. If the user takes the helmet off, then the output from the wear detection module 225 is logic low i.e., a 0 which indicates the removal of the helmet by the user.
[0057] A manner in which the wear detection logic of the wear detection module 225 in the processing module 205 is configured for wear detection of the helmet when the helmet is worn by the user is described in further detail below.
[0058] Figure 3 is a diagram showing a wear detection module 325 and its sub-systems configured for wear detection when the helmet is worn by the user, according to an embodiment of the present disclosure.
[0059] The wear detection module 325 has three sub-systems. The first sub-system is a sensor sub-system; the second sub-system is a microcontroller 320 and the third is a wear detection logic 310.
[0060] The helmet as disclosed uses the wear detection logic 310 to at least turn-on the helmet automatically when the user wears the helmet. This feature of the wear detection logic 310 provides convenience to the user. The wear detection module 325 in the disclosed helmet is implemented using the first data obtained from the sub-systems of the infrared module 102 and the second data obtained from the sub-systems of the inertial measurement unit 104.
[0061] To explain the technical advancement of the wear detection logic 310 in the wear detection module 325 of the disclosed system 100, let us consider a few examples.
[0062] In one example, a wear detection module may be implemented with the infrared module 102 only. But this implementation of a wear detection module, with only the infrared module 102, has certain limitations.
[0063] For example, consider the user is holding the helmet, which is tilted, and the user keeps the gloves inside the helmet. Because of the presence of these gloves inside the helmet, the infrared module 102 present in the helmet may detect the object or obstruction due to which it may give a false trigger to the wear detection logic 310 resulting in a logic 1 wear detection output.
[0064] To avoid this limitation, the disclosed system 100 as disclosed herein also includes the inertial measurement unit 104 along with the infrared module 102 and provides wear detection output 315 only when predefined conditions are satisfied. The predefined conditions are described in detail with examples in Figure 8, 9 and 10.
[0065] The inertial measurement unit 104 module as disclosed herein is configured to provide the second data indicating that the helmet is oriented within predefined limits for the three Euler angles and is also experiencing motion. The infrared module 102 as disclosed herein is configured for sensing the obstruction to the infrared radiation from the infrared transmitter to the infrared receiver for obtaining the first data indicating for the predefined duration.
[0066] As a result, in such cases where the first data and the second data are used, and where the helmet is tilted and the user keeps gloves or any other objects inside the helmet, then the wear detection logic 310 of the wear detection module 325 does not result in a false detection.
[0067] In another example, there is a possibility, where the infrared module 102 may include both the IR Tx and the IR Rx in the same hardware package. In such case, two sets of infrared modules 102 are needed, one set is placed on the inner right side of the helmet, and another is placed on the inner left side of the helmet.
[0068] In this implementation, the wear detection logic 310 output depends on the left side of the IR Rx and the right side of the IR Rx placed inside the helmet, resulting in the need of two IR sets to give the proper wear detection output. If the left side of the IR Rx output is high and the right-side IR Rx output is high, then only the wear detection logic 310 is triggered. The limitation of this implementation is that the IR hardware modules need to be placed in the helmet in such a way that the IR Rx gets the proper reflected signal otherwise there is a chance of incorrect wear detection results. Such drawbacks can be avoided by the wear detection module 325 of the disclosed system 100 comprising the inertial measurement unit 104 module configured to provide the second data indicating that the helmet is oriented within predefined limits for the three Euler angles and is experiencing motion. The infrared module 102 as disclosed herein is configured for sensing the obstruction to the infrared radiation from the infrared transmitter to the infrared receiver for obtaining the first data indicating for the predefined duration. As a result, in such a case, where the helmet is tilted and the user keeps gloves or any other objects inside the helmet, then the wear detection logic 310 of the wear detection module 325 does not trigger the false detection.
[0069] The sensor sub-system further comprises two components, the first is an infrared sensor sub-system (the component of the infrared module 102) and the second component is an inertial measurement unit sub-system (component of the inertial measurement unit 104). Each subsystem and its components are described in detail below.
[0070] Figure 4A illustrates a schematic of an infrared sensor as known in the state of the art. Figures 4B and 4C illustrate a schematic of an infrared sensor sub-system 402A, an infrared sensor sub-system 402B placed on left-hand side and an infrared sensor sub-system 402C placed on right-hand side of the printed circuit board respectively, according to an embodiment of the present disclosure.
[0071] As known in the state of the art, the infrared (IR) module includes an IR sensor which is an electronic device that emits a radiation in order to sense some object of the surroundings. Referring to Figure 4A, the IR transmitter (IR Tx) continuously emits IR radiation, and the IR detector (IR Rx) keeps on sensing the reflected radiation.
[0072] In an embodiment of the present disclosure, the IR transmitter of the infrared module emits the IR radiation, modulated at 38 kHz, continuously, and whenever it gets interfered with by some object, the IR detector changes its logic states from 0 to 1. This output of the IR detector is provided as an input to the microcontroller. The IR sensors implemented herein are configured to take very low supply current that reduces the power consumption. In addition, the angle of half sensitivity is chosen to be high. As known in the state of the art, the angle of half sensitivity indicates coverage of one-half of the angular zone within which radiation is accepted by the receiver’s concentrator. In one example, the angle of half sensitivity of the IR transmitter of the IR module implemented herein is chosen to be 60 degrees, nominal.
[0073] Referring to Figure 4B and 4C, a schematic for the printed circuit board of IR sensor 402B and 402C is shown. The printed circuit board includes IR Tx on one side and IR Rx on the other side (for example, left hand side and right-hand side). This circuit also consists of transient-voltage-suppression (TVS) diodes that prevent the circuit from Electrostatic Discharge (ESD). The values for the passives are configured and tuned for accurate results.
[0074] Figure 5A and 5B illustrate a placement of the IR transmitter and IR receiver on the inner surface of the helmet, according to an embodiment of the present disclosure. As shown in Figure 5A and 5B, the IR transmitter is positioned on the left side of the helmet and IR receiver is positioned on the right side of the helmet. When the user wears the helmet the output from the IR Rx becomes high i.e., logic 1. Whenever the user takes the helmet off then the output from the IR Rx becomes low i.e., logic 0. Hence, it is observed that, when there is no object in between the IR transmitter and IR receiver, then the IR receiver output is driven to Logic 0 and if any object is present in between the IR transmitter and IR receiver, then the IR receiver output is driven to Logic 1.
[0075] Figure 6A illustrates a block diagram of an inertial measurement unit sub-system 604A configured for providing an orientation data 618 of the helmet, according to an embodiment of the present disclosure.
[0076] In one embodiment, an inertial measurement unit (IMU) is an electronic device that measures and reports a body's specific force, angular rate, and the orientation of the body, using a combination of accelerometers, gyroscopes, and sometimes magnetometers. The IMU implemented in the disclosed helmet herein consists of a 3-axis gyroscope and an accelerometer. The 3-axis gyroscope provides a measure of angular orientation and an accelerometer provides a measure of specific force or acceleration. The combination of these sensors is used to improve accuracy. The IMU which has the accelerometers, and the gyroscope is used in the helmet disclosed herein. Usually, the gyroscope is used to sense orientation through angular velocity changes and therefore find orientation, but they tend to drift over time because they only sense changes and have no fixed frame of reference. The addition of an accelerometer’s data allows the bias in the gyroscope to be minimized and better estimated to reduce propagating error and improve orientation readings. The accelerometer’s sense changes in direction with respect to gravity which can orient the gyroscope to a more exact angular displacement. However, accelerometers are more accurate in static calculations, when the system is closer to its fixed reference point whereas the gyroscopes are better at detecting orientation when the system is already in motion.
[0077] Accelerometers tend to distort accelerations due to external forces such as gravitational forces in motion which accumulate as noise in the system and erroneous spikes in resulting outputs. While accelerometers sensors react quickly, accumulated errors in accelerometer jitter and noise are not reliable for the system alone. With the addition of the long-term accuracy of the gyroscope combined with the short-term accuracy of the accelerometer, these sensors can be combined to obtain more accurate orientation readings 618 by utilizing the benefits of each sensor. A few methods to apply sensor fusion are well known in the state of the art of varying degrees of complexity. A complimentary filter is a simple way to combine sensors, as it is a linear function of a high pass gyroscope filter and low pass accelerometer filter. Noisy accelerometer data with high frequencies are therefore filtered out in the short-term and smoothed out by smoother gyroscope reading. While the complimentary filter is computationally simple, it has a tendency to lag behind more involved techniques, such as the Kalman filter. While there are many variants of the Kalman filter that are more complex, a one-dimensional version can be implemented to the IMU disclosed herein to validate the estimate of the complimentary filter.
[0078] The Kalman filter takes a measured value and finds the future estimate by varying an averaging factor to optimize converging on the actual signal. The averaging factor is weighed by a measure of the predicted uncertainty, sometimes called the covariance, to pick a value somewhere between the predicted and measured value. The recursive functionality of the Kalman filter makes it a very popular sensor fusion method as it does not take a lot of processing power for a better behaving system. So, outputs of each sensor were combined in the technique disclosed herein by taking advantage of the benefits of both sensors to improve results. Gyroscopic drift was removed in the pitch and roll axes using the Kalman filter for both static and dynamic scenarios.
[0079] The microcontroller interfaced with IMU reads the data of accelerometer and gyroscope and the IMU data is given to the wear detection logic. The sensor fusion module 606 is an integral part of the wear detection module which is used for the detection of the orientation 618 of the helmet. The sensor fusion module 606 runs in the microcontroller using the Kalman filter or complimentary filter. The filter on the accelerometer and gyroscope data estimates the orientation 618 of the helmet. Based on the orientation 618 and IR receiver output data, the wear detection logic gives the output as wear is detected if the user wears the helmet or its opposite if the user takes the helmet off.
[0080] Figure 6B illustrates the placement 600B of the inertial measurement unit sub-system on the inner side of the helmet, according to an embodiment of the present disclosure. It is to be noted that, an exemplary placement of the inertial measurement unit sub-system on the inner side of helmet is shown in the Figure 6B, however, there is no limitation in placing the inertial measurement unit sub-system inside the helmet and can be placed anywhere inside the helmet.
[0081] Figure 7 illustrates a microcontroller sub-system 700 and its interface with the system 100 of Figure 1, according to an embodiment of the present disclosure. The microcontroller 720 is the heart of the disclosed system 100 configured to perform the desired actions. The microcontroller has a General-Purpose Input/Output (GPIO) which always reads the IR Rx output. This IR Rx output data is given as one of the inputs to the wear detection logic of the wear detection module. The IMU is interfaced with the microcontroller 720 through the Inter-Integrated Circuit (I2C) interface. The IMU reads the accelerometer and gyroscope data which are fed as an input to the wear detection logic of the wear detection module. The wear detection logic runs in the microcontroller and is responsible for the final wear detection logic output.
[0082] In one example, when the user wears the helmet, the microcontroller may be configured to play the helmet-on audio chime 715. In another example, when the user wears the helmet, the microcontroller 720 may be configured to turn-on the user-indication LED 715 and other internal components.
[0083] In one example, if the user takes the helmet off, then the wear detection logic of the wear detection module detects the event as the helmet removed state. In this example, the microcontroller 720 may be configured to play the helmet-off audio chime 715 and turn-off the user indication LED 715 to notify the user that the helmet is removed.
[0084] To explain the technical advancement of the wear detection logic 310 in the wear detection module 325 of the disclosed system 100, let us consider a few scenarios.
[0085] In one example, the state of the art helmets can be switched on or off through a button interface. In such scenarios, there is a possibility where the user takes the helmet off and may forget to turn-off the helmet and thereby leading to power consumption of the helmet, even though the user is not wearing the helmet. This problem can be avoided by using the automatic wear detection logic 310 of the disclosed system 100. The disclosed system 100 includes sensors with the speaker and mic (audio harness) that is hidden inside the helmet padding. The infrared module 102 and inertial measurement unit 104 are very well tuned and sensitive enough for detecting the wear with very less power consumption that will not affect the standby time of the helmet.
[0086] The helmet hardware contains the IR Rx and IR Tx. The inertial measurement unit 104 which sits on the PCB is kept inside a spoiler of the helmet that is having a gyroscope and the accelerometer that gives the (X, Y, Z) coordinates at different time intervals to the microcontroller. The microcontroller reads the IR Rx output data and the inertial measurement unit 104 data and gives this data as an input to the wear detection logic 310 of the wear detection module 325.
[0087] The wear detection logic 310 is configured to process this data for calculating the rotational angle of the helmet and uses the debounce mechanism on the IR RX output to avoid any false trigger on the IR RX output.
[0088] Then wear detection logic 310 gives the final output of the wear detection of the helmet. If the user wears the helmet, then the wear detection logic 310 gives the output as wear is detected. Then the helmet plays the helmet on audio through the connected speakers.
[0089] Figure 8 is a flow diagram for a wear detection logic 810 of the wear detection module, according to an embodiment of the present disclosure. The wear detection logic 810 uses the IR Rx output and IMU data as the input and it processes the data received and finally gives the actual wear detection output 815. Based on the wear detection output 815, the helmet is configured to perform one or more specific actions.
[0090] The wear detection logic 810 runs in a loop in the microcontroller firmware. This wear detection logic 810 performs the two major operations – detection of (i) Helmet-on state and (ii) Helmet-off state.
[0091] (i) Helmet-on state: When the user wears the helmet, the IR Rx output goes to logic high state i.e., 1 and if the helmet is worn with a proper orientation i.e., the helmet is not tilted beyond predefined limits then the helmet wear detection logic considers the wear detection output as helmet-on state. When the helmet is on state, the helmet is configured to perform the defined tasks.
[0092] (ii) Helmet-off state: When the user takes the helmet off, the IR Rx output goes to logic low i.e., 0 and then the helmet wear detection logic considers the wear detection output as helmet-off state. When the helmet is off state, the helmet is configured to perform the defined tasks.
[0093] Figure 9A and 9B illustrate a flow chart depicting a method 900A for wear detection (Helmet-on state) and a method 900B for wear removal (Helmet-off state) respectively, according to an embodiment of the present disclosure. The order in which the method steps are described below is not intended to be construed as a limitation, and any number of the described method steps can be combined in any appropriate order to execute the method or an alternative method. Additionally, individual steps may be deleted from the method, without departing from the spirit and scope of the subject matter described herein.
[0094] The method 900A as shown in Figure 9A for wear detection may mean detecting that the helmet is worn by the user and at least turning on an electronic unit inside the helmet when the helmet is worn by the user.
[0095] At step 932A, the method includes obtaining infrared receiver (IR Rx) output data. The IR Rx output data is the first data obtained by sensing the obstruction to the infrared radiation from the at least one infrared transmitter to the at least one infrared receiver.
[0096] At step 934A, the method includes obtaining the inertial measurement unit (IMU) data. The IMU data is the second data is obtained by combining motion of the helmet sensed by an accelerometer of the inertial measurement unit and a gyroscope sensing the orientation of the helmet having three Euler angles within predefined ranges for each of them.
[0097] At steps 932A and 934A, the microcontroller is configured to read the IR Rx output data and IMU raw data. At this step, the IR Rx output data and IMU data is fed as an input to the wear detection module.
[0098] At step 936A, the method includes calculating the orientation of the helmet using the IMU data. At this step, the wear detection module uses the IMU data and calculates the rotational angle of the helmet. The calculated rotational angle is used to decide whether the helmet is tilted or not.
[0099] At step 938A, it is checked if the output of IR Rx is high and the calculated rotational angles of the helmet are within predefined limits for each, then the wear detection module gives the output as the Helmet-on state. This implies that the wear of the helmet is detected. At step 940A, the method includes detecting the helmet worn by the user based on the decision at step 938A.
[0100] Referring to Figure 9B, the method 900B as shown for wear removal may mean detecting that the helmet is not worn by the user and at least turning off an electronic unit inside the helmet.
[0101] At step 932B, the method includes obtaining infrared receiver (IR Rx) output data. The IR Rx output data is the first data obtained by sensing the obstruction to the infrared radiation from the at least one infrared transmitter to the at least one infrared receiver.
[0102] At step 934B, the method includes obtaining the inertial measurement unit (IMU) data. The IMU data is the second data is obtained by combining motion of the helmet sensed by an accelerometer of the inertial measurement unit and a gyroscope sensing the orientation of the helmet having three Euler angles within predefined ranges for each of them.
[0103] At steps 932B and 934B, the microcontroller is configured to read the IR Rx output data and IMU raw data. At this step, the IR Rx output data and IMU data is fed as an input to the wear detection module.
[0104] At step 936B, the method includes calculating the orientation of the helmet using the IMU data. At this step, the wear detection module uses the IMU data and calculates the rotational angle of the helmet. The calculated rotational angle is used to decide whether the helmet is tilted or not.
[0105] The wear removal (Helmet-off state) state is triggered in the below cases.
[0106] Step 938B: If the IR Rx output is low and the rotational angle of the helmet is not within the predefined limit and the helmet is static, then the output of the wear detection logic of the wear detection module is Helmet-off state (940B). This implies that the helmet is not worn by the user.
[0107] Step 938C: If the IR Rx output is low and the rotational angle of the helmet is within the predefined limit and is experiencing motion, then the output of the wear detection logic of the wear detection module is Helmet-off state (940B). This implies that the helmet is not worn by the user.
[0108] Step 938D: If the IR Rx output is high and the rotational angle of the helmet is not within the predefined limit and the helmet is static, then the output of the wear detection logic of the wear detection module is Helmet-off state (940B). This implies that the helmet is not worn by the user.
[0109] Figure 10 illustrates a truth table 1000 showing the output of the method 900A and 900B for wear detection (Helmet-on state) and wear removal (Helmet-off state) respectively, according to an embodiment of the present disclosure. In particular, the table 1000 illustrates the wear detection logic output state. The table 1000 illustrates the decision that the user either wears the helmet or takes the helmet off. Below are the scenarios shown in Figure 10.
[0110] Case 1: If the IR Rx output (1002A) is low and the helmet rotational angle is not in the predefined limit and the helmet is static (1002B), then the wear detection logic indicates that the user has removed the helmet (1002).
[0111] Case 2: If the IR Rx output (1004A) is low and the helmet rotational angle is in the predefined limit and is experiencing motion (1004B), then the wear detection logic indicates that the user has removed the helmet (1004).
[0112] Case 3: If the IR Rx output (1006A) is high and the helmet rotational angle is not in the predefined limit and the helmet is static (1006B), then the wear detection logic indicates that the user has removed the helmet (1006).
[0113] Case 4: If the IR Rx Output (1008A) is high and the helmet rotational angle is in the predefined limit and the helmet is experiencing motion (1008B) then, the wear detection logic indicates that the user has worn the helmet (1008).
[0114] Thus, the system 100 and its components as disclosed herein are configured for wear detection of a helmet when the helmet is worn by a user and turning on the Smart Helmet and its functionalities. The system 100 works by using the Sensor Integration and the Inertial Measurement unit. The whole electronics of the system 100 is embedded inside the disclosed Helmet considering the negligible interference with the environment.
[0115] It will be appreciated that the modules, processes, systems, and devices described above can be implemented in hardware, hardware programmed by software, software instruction stored on a non-transitory computer readable medium or a combination of the above. Embodiments of the methods, processes, modules, devices, and systems (or their sub-components or modules), may be implemented on a general-purpose computer, a special-purpose computer, a programmed microprocessor or microcontroller and peripheral integrated circuit element, an ASIC or other integrated circuit, a digital signal processor, a hardwired electronic or logic circuit such as a discrete element circuit, a programmed logic circuit such as a programmable logic device (PLD), programmable logic array (PLA), field-programmable gate array (FPGA), programmable array logic (PAL) device, or the like. In general, any process capable of implementing the functions or steps described herein can be used to implement embodiments of the methods, systems, or computer program products (software program stored on a non-transitory computer readable medium).
[0116] Furthermore, embodiments of the disclosed methods, processes, modules, devices, systems, and computer program products may be readily implemented, fully or partially, in software using, for example, object or object-oriented software development environments that provide portable source code that can be used on a variety of computer platforms. Alternatively, embodiments of the disclosed methods, processes, modules, devices, systems, and computer program products can be implemented partially or fully in hardware using, for example, standard logic circuits or a very-large-scale integration (VLSI) design. Other hardware or software can be used to implement embodiments depending on the speed and/or efficiency requirements of the systems, the particular function, and/or particular software or hardware system, microprocessor, or microcomputer being utilized.
[0117] In this application, unless specifically stated otherwise, the use of the singular includes the plural and the use of “or” means “and/or.” Furthermore, use of the terms “including” or “having” is not limiting. Any range described herein will be understood to include the endpoints and all values between the endpoints. Features of the disclosed embodiments may be combined, rearranged, omitted, etc., within the scope of the invention to produce additional embodiments. Furthermore, certain features may sometimes be used to advantage without a corresponding use of other features.

[0118] List of reference numerals:
Components Reference numerals
System 100
Infrared module 102
Inertial measurement unit 104
Processing module 105, 205
Wear detection output 115,215, 315, 715, 815
Microcontroller 220, 320, 720
Infrared receiver data, IR Rx output 202A, 502A, 702A, 802A
IMU data 204A, 604A, 704A, 804A
Sensor fusion module 206, 606
Wear detection module 225, 325
Sensor Sub-System 312
Wear detection logic 210, 310, 810
IR Tx 502B
Foam padding 524
Kalman/
complementary filter 616
Helmet orientation 618
Position of Inertial measurement unit
604B
, Claims:1. A system (100) for wear detection of a helmet when the helmet is worn by a user, the system (100) comprising:
an infrared module (102) having at least one infrared transmitter and at least one infrared receiver positioned separately on the inner surface of the helmet, the infrared module (102) configured for sensing an obstruction to the infrared radiation from the at least one infrared transmitter to the at least one infrared receiver, for obtaining a first data;
an inertial measurement unit (104), positioned inside the helmet, configured for detecting an orientation of the helmet, within predefined limits for the orientation, for obtaining a second data; and
a processing module (105) configured for receiving and processing the first data and the second data for detecting (115) a wear state of the helmet when each of the first data and the second data satisfy respective predefined conditions.

2. The system (100) as claimed in claim 1, wherein the predefined conditions for detecting the state of the helmet as the helmet worn (1008) by the user comprise:
(a) the first data (1008A) indicating an obstruction, for a predefined duration; and
(b) the second data (1008B) indicating that the helmet is oriented within predefined limits and is experiencing motion.

3. The system (100) as claimed in claim 1, wherein the predefined conditions for detecting the wear state of the helmet as:
(i) the helmet is not worn (1002) by the user when:
(c) the first data (1002A) is indicating no obstruction, for the predefined duration; and
(d) the second data (1002B) indicating that the helmet is oriented outside the predefined limits and indicating that it is static;
(ii) the helmet is not worn (1004) by the user when: and
(e) the first data (1004A) is indicating no obstruction, for the predefined duration; and
(f) the second data (1004B) is indicating that the helmet is oriented within the predefined limits and is experiencing motion;
(iii) the helmet is not worn (1006) by the user when:
(g) the first data (1006A) is indicating obstruction, for the predefined duration; and
(h) the second data (1006B) is indicating that the helmet is oriented outside the predefined limits and indicating that it is static.

4. The system (100) as claimed in claim 1, wherein the processing module (105) comprises one or more sub-systems, the one or more sub-systems comprising: a sensor sub-system (312), a microcontroller (320), and a wear detection logic (310).

5. The system (100) as claimed in claim 4, wherein the sensor sub-system (312) comprises:
a. a low power infrared sensor sub-system comprising an IR sensor with predefined angle of half sensitivity; and
b. an inertial measurement unit sub-system comprising one or more accelerometers and at least one gyroscope.

6. The system (100) as claimed in claim 1, wherein the second data is obtained by combining motion of the helmet sensed by the one or more accelerometers of the inertial measurement unit sub-system and the gyroscope sensing the orientation of the helmet having three Euler angles within predefined ranges for each of them.

7. The system (100) as claimed in claim 4, wherein the microcontroller (320) is configured for receiving the first data and the second data.

8. The system (100) as claimed in claim 5, wherein the wear detection logic (310) is configured for processing the first data and the second data for detecting the wear state of the helmet when the helmet is worn by the user when each of the first data and the second data satisfy the respective predefined conditions.

9. The system (100) as claimed in claim 2, wherein the predefined duration is determined for debouncing the first data.

10. A method (900A) for wear detection of a helmet when the helmet is worn by a user, the method (900A) comprising:
sensing, within the helmet, an obstruction to an infrared radiation emitted by at least one infrared transmitter toward at least one infrared receiver of an infrared module (102), for obtaining (932A) a first data;
detecting (936A) an orientation of the helmet, within predefined limits, for the orientation of the helmet, using an inertial measurement unit (104) for obtaining a second data (934A);
receiving and processing the first data and the second data for detecting (115) a wear state of the helmet when each of the first data and the second data satisfy respective predefined conditions.

11. The method as claimed in claim 10, wherein the predefined conditions for detecting (940A) the state of the helmet as the helmet worn (1008) by the user comprise:
(i) the first data (1008A) indicating an obstruction, for a predefined duration; and
(j) the second data (1008B) indicating that the helmet is oriented within predefined limits and is experiencing motion.

12. The method as claimed in claim 10, detecting the state of the helmet as:
(iv) the helmet is not worn (1002) by the user when:
(k) the first data (1002A) is indicating no obstruction, for the predefined duration; and
(l) the second data (1002B) indicating that the helmet is oriented outside the predefined limits and indicating that it is static;
(v) the helmet is not worn by (1004) the user when:
(m) the first data (1004A) is indicating no obstruction, for the predefined duration; and
(n) the second data (1004B) is indicating that the helmet is oriented within the predefined limits and is experiencing motion;
(vi) The helmet is not worn (1006) by the user when:
(o) the first data (1006A) is indicating obstruction, for the predefined duration; and
(p) the second data (1006B) is indicating that the helmet is oriented outside the predefined limits and indicating that it is static.
13. The method as claimed in claim 10, obtaining the second data by combining motion of the helmet sensed by an accelerometer of the inertial measurement unit (104) and a gyroscope sensing the orientation of the helmet having three Euler angles within predefined ranges for each of them.

14. A helmet for wear detection, when worn by a user, the helmet comprising:
an infrared module (102) comprising at least one infrared transmitter and at least one infrared receiver positioned separately on the inner surface of the helmet; wherein the at least one infrared transmitter is positioned on a first inner side of the helmet and the at least one infrared receiver is positioned on a second inner side of the helmet such that the at least one infrared receiver is capable of sensing the infrared radiation from the at least one infrared transmitter, in the absence of an obstruction between the at least one infrared transmitter and the at least one infrared receiver;
an inertial measurement unit (104), positioned inside the helmet, comprising one or more accelerometers and at least one gyroscope; and
a processing module (105) communicatively coupled to the infrared module (102) and the inertial measurement unit (104).

15. The helmet as claimed in claim 14,
wherein the infrared module (102) is configured for sensing the obstruction to the infrared radiation from the at least one transmitter to the at least one infrared receiver for obtaining a first data,
wherein the inertial measurement unit (104), positioned inside the helmet is configured for detecting an orientation of the helmet within predefined limits for obtaining a second data; and
the processing module (105) configured for receiving and processing the first data and the second data for detecting a wear state of the helmet when each of the first data and the second data satisfy respective predefined conditions.

16. The helmet as claimed in claim 15, wherein the predefined conditions comprise:
a. the first data indicating, for a predefined duration; and
b. the second data indicating that the helmet is oriented within predefined limits and is experiencing motion.

17. The helmet as claimed in claim 15, wherein the second data is obtained by combining motion of the helmet sensed by the one or more accelerometers of the inertial measurement unit (104) and the at least one gyroscope sensing the orientation of the helmet having three Euler angles within predefined ranges for each of them.

18. The helmet as claimed in claim 14, wherein a plurality of pairs of infrared transmitters and infrared receivers are placed inside the helmet for sensing obstructions to reception of infrared radiation by the plurality of infrared receivers.

19. The helmet as claimed in claim 14, wherein individual infrared transmitters and receivers are encased in protective enclosures for protecting them from environment and are covered with cushioning material for wearer comfort.