Magnetic multimedia control element

A magnetic sensor may include a set of elements to detect a set of magnetic field strengths of a magnetic field generated by a magnet, and determine, based on the set of magnetic field strengths, a state of an object with respect to multiple degrees of freedom of object movement. The magnet may be connected to the object such that a center of the magnet is offset from an axis of rotation of the object and such that the magnet is angled with respect to a direction that is substantially perpendicular to the axis of rotation when the object is in an un-tilted position. The magnetic sensor may be substantially centered on the axis of rotation of the object when the object is in the un-tilted position.

BACKGROUND

A magnetic sensor may be capable of sensing multiple (e.g., perpendicular) components of a magnetic field applied to the magnetic sensor, such as an x-component, a y-component, and a z-component. The magnetic sensor may be used to detect, for example, movement, position, an angle of rotation, and/or the like, of a magnet, connected to an object, in a variety of applications, such as an automotive application, an industrial application, or a consumer application.

SUMMARY

According to some possible implementations, a magnetic sensor may include a set of elements to: detect a set of magnetic field strengths of a magnetic field generated by a magnet; and determine, based on the set of magnetic field strengths, a state of an object with respect to multiple degrees of freedom of object movement, where the magnet is connected to the object such that a center of the magnet is offset from an axis of rotation of the object and such that the magnet is angled with respect to a direction that is substantially perpendicular to the axis of rotation when the object is in an un-tilted position, and where the magnetic sensor is substantially centered on the axis of rotation of the object when the object is in the un-tilted position.

According to some possible implementations, an apparatus may include: a magnet connected to an object capable of being positioned with respect to multiple degrees of freedom, where the magnet is connected to the object such that a center of the magnet is offset from an axis of rotation of the object and such that the magnet is angled with respect to a direction that is perpendicular to the axis of rotation; and a magnetic sensor to: determine a state of the object, with respect to the multiple degrees of freedom, based on a set of magnetic field strengths of a magnetic field generated by the magnet, where the magnetic sensor is substantially centered on the axis of rotation when the object is in an un-tilted position.

According to some possible implementations, a system may include: an object capable of being positioned with respect to multiple degrees of freedom; a magnet asymmetrically connected to the object such that a center of the magnet is offset from an axis of rotation of the object and such that the magnet is angled with respect to a direction that is substantially perpendicular to the axis of rotation; and a magnetic sensor to determine a state of the object, with respect to the multiple degrees of freedom, based on a magnetic field applied to the magnetic sensor by the magnet, the magnetic sensor being substantially centered on the axis of rotation when the object is in an un-tilted position.

DETAILED DESCRIPTION

A tilt position, a linear position, and a rotational position of an object (herein collectively referred to as a “state” of the object) may be of interest in a given application. For example, a control element, included in a vehicle, may allow a user (e.g., a driver of an automobile) to control one or more systems of the vehicle (e.g., a multimedia system, a navigation system, an audio system, a telephone system, and/or the like) by manipulating the state the control element.

In some cases, the object may be positioned with respect to four degrees of freedom: a tilt position with respect to a first direction (e.g., an x-direction), a tilt position with respect to a second direction (e.g., a y-direction), a linear position along a third direction (e.g., a “push-button” position along a z-direction), and a rotational position (e.g., when not tilted with respect to the first direction or the second direction, when tilted with respect to the first direction and/or the second direction, when in the push-button position along the third direction, when not in the push-button position along the third direction, and/or the like).

In such cases, multiple sensor systems, sometimes using different sensing principles, may be implemented in order to detect the state of the object. For example, optical sensor systems (e.g., a pair of optical sensor systems including photodiodes, light guides, light emitting diodes, and/or the like) may be used to detect the tilt of the object with respect to the first direction and the second direction, a sensor system including a set of tactile switches may be used to detect the position along the third direction (i.e., whether the control element is in the push-button position or is not in the push-button position), and an incremental optical encoder sensor system may be used to detect the rotational position of the object. However, implementing these multiple sensor systems may come with a substantial cost and/or complexity.

Implementations described herein provide a magnetic sensor system, including a single magnetic sensor and a single magnet, that is capable of detecting a state of an object with respect to four degrees of freedom: a tilt with respect to a first direction, a tilt with respect to a second direction, a position along a third direction, and a rotational position (e.g., on a plane associated with the first direction and the second direction).

Here, since a single magnetic sensor and a single magnet are needed, the magnetic sensor system has a reduced complexity and/or a reduced cost (e.g., as compared to an implementation that uses multiple sensor systems to detect the state of the object). Moreover, the magnetic sensor system provides for absolute encoding of the state of the object, thereby reducing complexity and/or increasing reliability of detecting the state of the object. Further, due to the use of magnetic sensing principles, the magnetic sensor system described herein has an increased lifetime (e.g., due to contact-free, and thus wear-free, operation), an increased potential for miniaturization, and an increased robustness against, for example, temperature variation and dirt.

FIG. 1is a diagram of an overview of an example implementation100described herein. As shown inFIG. 1, an object may be positioned in a state described by four degrees of freedom, including (1) a tilt position with respect to an x-direction, (2) a tilt position with respect to a y-direction, (3) a linear (or push) position with respect to a z-direction, and (4) a rotational position with respect to (approximately) an xy-plane. As described above, the state of the object may be of interest in a given application, such as when the object is part of a control element that allows a user to control a system in, for example, an automobile.

As further shown inFIG. 1, a magnet may be asymmetrically connected to the object. For example, as shown in the left portion ofFIG. 1, a center of the magnet may be offset from an axis of rotation of the object by a particular distance. Further, as shown in the right portion ofFIG. 1, the magnet may be arranged such that the magnet is rotated about the center of the magnet by a particular magnet angle (i.e., such that a plane separating poles of the magnet is not perpendicular to the x-direction or the y-direction).

As further shown, a magnetic sensor may be arranged relative to the object and the magnet. For example, as shown in the left portion ofFIG. 1, the magnetic sensor may be arranged such that the magnetic sensor is centered on the axis of rotation (e.g., when the object is not tilted). As further shown, the magnetic sensor may be arranged such that the magnetic sensor is separated from the magnet by an air gap of a particular distance (e.g., when the object is not tilted).

During operation, the magnetic sensor may sense components (e.g., an x-component, a y-component, and a z-component) of the magnetic field generated by the magnet. As noted, inFIG. 1, the magnetic sensor may determine the state of the object, with respect to the four degrees of freedom, based on the sensed components of the magnetic field. For example, the magnetic sensor may determine the state of the object based on mapping information that associates possible states of the object with corresponding sets of magnetic field strengths within a three-dimensional magnetic space. Here, each possible state of the object may be uniquely represented in the three-dimensional magnetic space as a result of the asymmetrical mounting of the magnet with respect to the object and the magnetic sensor. Additional details regarding the arrangement and operation of the magnetic sensor system are described below.

In this way, a magnetic sensor system, including a single magnetic sensor and a single magnet, may determine a state of an object with respect to multiple degrees of freedom. The multiple degrees of freedom may include, for example a tilt with respect to a first direction, a tilt with respect to a second direction, a position along a third direction, and a rotational position (e.g., on a plane associated with the first direction and the second direction).

FIGS. 2A and 2Bare diagrams of an example environment200in which apparatuses described herein may be implemented. As shown inFIG. 2A, environment200may include an object205that may be positioned (e.g., via tilting, linear movement, and/or rotation) with respect to a center of tilt210and axis of rotation212(as described below), a magnet215connected (e.g., mechanically connected) to object205, a magnetic sensor220, and a controller225.

Object205includes an object for which a state (e.g., a tilt position, a linear position, a rotational position, and/or the like) is of interest for a given application. For example, object205may include a control element (e.g., a joystick, a knob, a dial, a wheel, a button, or any combination thereof) included in, for example, a vehicle for use in controlling a system, such as a multimedia system, a navigation system, an audio system, a telephone system, and/or the like. In some implementations, object205is connected (e.g., attached to, coupled with, affixed to, embedded in, and/or the like) to magnet215, as described below.

In some implementations, object205is capable of tilting (e.g., about center of tilt210) with respect to a first direction (e.g., an x-direction) and a second direction (e.g., a direction that is substantially perpendicular to the x-direction, such as a y-direction) such that object205may be in multiple tilt positions. For example, as shown inFIG. 2A, if object205is not tilted with respect to the x-direction or the y-direction, then object205may be in an un-tilted position (T0). As shown, if object205is tilted in a first direction with respect to the x-direction (a left direction as shown inFIG. 2A), then object205may be in a first x-tilt position (Tx1). As further shown, if object205is tilted in a second direction with respect to the x-direction (a right direction as shown inFIG. 2A), then object205may be in a second x-tilt position (Tx2). Similarly, while not shown, if object205is tilted in a first direction with respect to the y-direction (e.g., into the page ofFIG. 2A), then object205may be in a first y-tilt position (Ty1), and if object205is tilted in a second direction with respect to the y-direction (e.g., out of the page ofFIG. 2A), then object205may be in a second y-tilt position (Ty2). In other words, in some implementations, object205may be capable of being positioned in multiple tilt positions (e.g., three tilt positions, five tilt positions, nine tilt positions, and/or the like). For example, in example environment200, object205is capable of being positioned in five tilt positions (e.g., T0, Tx1, Tx2, Ty1, and Ty2).

In some implementations, object205is capable of being positioned in at least two linear positions along a third direction (e.g., a direction that is substantially perpendicular to the x-direction and the y-direction, such as a z-direction). For example, as shown inFIG. 2A, if object205is in not in a pushed position (e.g., when the control element is not pressed into a push-button position), then object205may be in a first linear position (Pz1) along the z-direction. As further shown, if object205is in the pushed position (e.g., when the control element is pressed into the push-button position), then object205may be in a second linear position (Pz2) along the z-direction.

In some implementations, object205may be in linear position Pz2only when object205is positioned at tilt position T0(i.e., push-button may be enabled only when object205is not tilted). Alternatively, in some implementations, object205may be in the pushed position when object205is tilted with respect to the x-direction and/or the y-direction. In some implementations, object205may be capable of being positioned in multiple linear positions (e.g., two linear positions, three linear positions, five linear positions, and/or the like). For example, in example environment200, object205is capable of being positioned in two linear positions (e.g., Pz1and Pz2).

As shown inFIG. 2B, in some implementations, object205is capable of rotating about axis of rotation212(e.g., an axis that is substantially parallel to (i.e., aligned with) the z-direction and that passes through center of tilt210) such that object205may be positioned in multiple rotational positions. For example, object205may be positioned in n (n>1) rotational positions R1through Rn. In some implementations, the number of n rotational positions may be, for example, 8, 16, 32, 44, and/or the like. InFIG. 2B, object205is in a particular rotational position Rnof 32 possible rotational positions. As shown inFIG. 2A, in some implementations, each of the n rotational positions may be evenly spaced about axis of rotation212. Alternatively, two or more of the n rotational positions may be unevenly spaced about axis of rotation212. In some implementations, object205may be in any of the n rotational positions while object205is in any tilt position and/or in any linear position.

In some implementations, object205may be in one of multiple states, where each state is associated with a tilt position, a linear position, and/or rotational position. For example, using the examples described above, assume that at a given time, object205may be in the pushed position or the non-pushed position, and that, while in the non-pushed position, object205may also be in one of five tilt positions and one of 32 rotational positions (assume that tilt position and rotational position are not of interest while object205is in the pushed position). In this example, object205has 161 possible states (e.g., 1+(32×5)=161). In some implementations, each possible state of object205may be mapped to a corresponding set of magnetic field strengths in order to allow the state of object205to be determined based on sensing components of a magnetic field produced by magnet215, as described below.

Magnet215includes a magnet that is connected (e.g., attached, coupled, affixed, and/or the like) to object205such that a state of magnet215corresponds to a state of object205, as described herein. In some implementations, magnet215comprises a first half forming a north pole (N) and a second half forming a south pole (S), so that magnet215comprises one pole pair. For example, as shown inFIGS. 2A and 2B, magnet215may include a diametrally magnetized magnet with a north pole on a first half of magnet215and a south pole on a second half of magnet215. As another example, magnet215may include an axially magnetized magnet with a north pole on a first half of magnet215that is stacked (e.g., along the z-direction) on a south pole on a second half of magnet215(not shown). Additionally, or alternatively, magnet215may include a dipole magnet (e.g., a dipole bar magnet, a circular dipole magnet, an elliptical dipole magnet, etc.), a permanent magnet, an electromagnet, a magnetic tape, and/or the like. In some implementations, magnet215may, without limitation, comprise more than one pole pair.

In some implementations, magnet215may be comprised of a ferromagnetic material (e.g., Hard Ferrite), and may produce a magnetic field. In some implementations, magnet215may further comprise a rare earth magnet, which may be of advantage due to an intrinsically high magnetic field strength of rare earth magnets. In some implementations, magnet215may be a homogeneously magnetized magnet with a residual induction (Br) in range from 150 millitesla (mT) to approximately 1400 mT, such as 1000 mT.

In some implementations, a dimension of magnet215(e.g., a length, a width, a height, a diameter, a radius, and/or the like) may be in a range from approximately 1 millimeter (mm) to approximately 15 mm, such as 3 mm. As a particular example, magnet215may have a length, a width, and a height of approximately 3 mm (i.e., magnet215may be a 3 mm×3 mm×3 mm cube). Notably, while magnet215is shown as having a square shape inFIGS. 2A and 2B, magnet215may have another shape, such as a rectangular shape, a circular shape, an elliptical shape, a triangular shape, a ring shape, and/or the like.

In some implementations, magnet215may be connected to object205in an asymmetric manner. For example, as shown in bothFIGS. 2A and 2B, magnet215may be connected to object205such that a center of magnet215is arranged at an offset distance dofrom axis of rotation212. In some implementations, distance domay be in a range from approximately 0.2 mm to approximately 5.0 mm, such as 0.5 mm.

As further shown inFIG. 2A, magnet215may be arranged such that center of tilt210is an axial distance dmfrom a closest surface of magnet215(e.g., a top surface inFIG. 2A). In some implementations, the distance dmmay be in a range from approximately 5 mm to approximately 30 mm. In some implementations, the distance dmmay be selected in order to provide sufficient magnetic state separation between states of object205(e.g., magnetic state separation that allows each state of object205to be reliably mapped and/or identified), as described herein. For example, assume that each of tilt positions Tx1, Tx2, Ty1, and Ty2of object205has an angle of approximately 5 degrees (in the respective tilt directions) with respect to axis of rotation212, that magnet215is a 3 mm cube, and that sufficient magnetic state separation is achieved when magnet215shifts by at least 1 mm between tilt position T0and any of Tx1, Tx2, Ty1, and Ty2. In this example, distance dmmay be selected to be approximately 12.6 mm, which results in magnet215shifting by at least 1 mm between tilt position T0and any other tilt position (e.g., since 12.6 mm×tan(5°)=1.0 mm). In some implementations, the distance dmmay be selected such that a surface of magnet215extends (e.g., in the z-direction) beyond a surface of object205, as shown inFIG. 2A. Alternatively, the distance dmmay be selected such that the surface of magnet215is flush with the surface of object205or such that the surface of object205extends beyond the surface of magnet215(not shown).

As shown inFIG. 2B, magnet215may be arranged such that magnet215is angled with respect to the x-direction and the y-direction (e.g., at magnet angle θMwith respect to the x-direction and the y-direction). In some implementations, magnet angle θMmay be in a range from approximately 10° to approximately 80°, such as approximately 57°.

In some implementations, the asymmetric mounting of magnet215(e.g., arranging at distance doand at magnet angle θM) provides for magnetic state separation among states of object205such that the state of object205may be reliably identified by magnetic sensor220, as described below.

Magnetic sensor220includes one or more apparatuses for sensing components of a magnetic field for use in determining a state of object205(e.g., based on a state of magnet215relative to magnetic sensor220). For example, magnetic sensor220may include one or more circuits (e.g., one or more integrated circuits) that operate to sense an x-component of a magnetic field produced by magnet215, a y-component of the magnetic field produced by magnet215, and a z-component of the magnetic field produced by magnet215(i.e., magnetic sensor220may be a 3D magnetic sensor). In some implementations, magnetic sensor220may include an integrated circuit that includes an integrated controller225(e.g., such that an output of magnetic sensor220may include information that describes a state of magnet215and/or a state of object205). In some implementations, magnetic sensor220may include sensing elements configured to sense the components of the magnetic field produced by magnet215. In some implementations, magnetic sensor220may be capable of sensing magnetic field strengths of approximately 150 mT in order to increase stray field robustness (e.g., as compared to a magnetic sensor capable of sensing magnetic fields strengths less than 150 mT). Additional details regarding magnetic sensor220are described below with regard toFIG. 3.

In some implementations, magnetic sensor220may be arranged at a position relative to magnet215such that magnetic sensor220may detect components of a magnetic field produced by magnet215. For example, as shown inFIG. 2A, magnetic sensor220may be arranged such that magnetic sensor220is centered on axis of rotation212with an air gap distance (da) between magnetic sensor220and magnet215(e.g., when object is in tilt position T0). Here, magnetic sensor220may be capable of sensing an x-component, a y-component, and a z-component of the magnetic field produced by magnet215.

In some implementations, magnetic sensor220may be configured with mapping information associated with determining the state of object205based on the sensed components of the magnetic field. The mapping information may include information associated with a state (e.g., information that identifies a tilt position, a linear position, and/or a rotational position corresponding to the state) and a set of magnetic field strengths, corresponding to the state, including a magnetic field strength in the x-direction, a magnetic field strength in the y-direction, and a magnetic field strength in the z-direction. The mapping information may include such information for multiple states. For example, using the example described above, the mapping information may include information associated with 161 possible states of object205and 161 sets of magnetic field strengths, each corresponding to a different one of the 161 possible states. In some implementations, magnetic sensor220may be configured with the mapping information during a manufacturing process associated with the magnetic sensor system, a calibration process associated with the magnetic sensor system, a setup process associated with the magnetic sensor system, and/or the like.

During operation, magnetic sensor220may sense the x-component of the magnetic field produced by magnet215, the y-component of the magnetic field produced by magnet215, and the z-component of the magnetic field produced by magnet215. Magnetic sensor220may then compare the sensed magnetic field strengths to the mapping information, and determine the state of object based on the comparison. For example, magnetic sensor220may identify a set of magnetic field strengths, included in the mapping information, that match (e.g., within a threshold) the sensed components of the magnetic field (e.g., a set of magnetic field strengths including a magnetic field strength in the x-direction that matches the sensed x-component of the magnetic field, a magnetic field strength in the y-direction that matches the sensed y-component of the magnetic field, and a magnetic field strength in the z-direction that matches the sensed z-component of the magnetic field). In this example, magnetic sensor220may determine the state of object205as the state corresponding to the matched mapping information.

Controller225may include one or more circuits associated with determining a state of object205, and providing information associated with the state of object205. For example, controller225may include one or more circuits (e.g., an integrated circuit, a control circuit, a feedback circuit, etc.). Controller225may receive input signals from one or more sensors, such as one or more magnetic sensors220, may process the input signals (e.g., using an analog signal processor, a digital signal processor, etc.) to generate an output signal, and may provide the output signal to one or more other devices or systems. For example, controller225may receive one or more input signals from magnetic sensor220, and may use the one or more input signals to generate an output signal comprising the state of object205to which magnet215is connected.

The number and arrangement of apparatuses shown inFIGS. 2A and 2Bare provided as an example. In practice, there may be additional apparatuses, fewer apparatuses, different apparatuses, or differently arranged apparatuses than those shown inFIGS. 2A and 2B. Furthermore, two or more apparatuses shown inFIGS. 2A and 2Bmay be implemented within a single apparatus, or a single apparatus shown inFIGS. 2A and 2Bmay be implemented as multiple, distributed apparatuses. Additionally, or alternatively, a set of apparatuses (e.g., one or more apparatuses) of environment200may perform one or more functions described as being performed by another set of apparatuses of environment200.

FIG. 3is a diagram of example elements of magnetic sensor220included in example environment200ofFIG. 2. As shown, magnetic sensor220may include a set of sensing elements310, an analog-to-digital convertor (ADC)320, a digital signal processor (DSP)330, an optional memory element340, and a digital interface350.

Sensing element310includes an element for sensing a component of a magnetic field present at magnetic sensor220(e.g., the magnetic field generated by magnet215). For example, sensing element310may include a Hall-based sensing element that operates based on a Hall-effect. As another example, sensing element310may include a MR-based sensing element, elements of which are comprised of a magnetoresistive material (e.g., nickel-iron (NiFe)), where the electrical resistance of the magnetoresistive material may depend on a strength and/or a direction of the magnetic field present at the magnetoresistive material. Here, sensing element310may operate based on an anisotropic magnetoresistance (AMR) effect, a giant magnetoresistance (GMR) effect, a tunnel magnetoresistance (TMR) effect, and/or the like. As an additional example, sensing element310may include a variable reluctance (VR) based sensing element that operates based on induction. In some implementations, magnetic sensor220may include multiple sensing elements310. For example, magnetic sensor220may include a first sensing element310(e.g., including a first set of vertical Hall plates) that operates to sense an x-component of the magnetic field, a second sensing element310(e.g., including a second set of vertical Hall plates) that operates to sense y-component of the magnetic field, and a third sensing element310(e.g., including a set of lateral Hall plates) that operates to sense a z-component of the magnetic field.

ADC320may include an analog-to-digital converter that converts an analog signal from the set of sensing elements310to a digital signal. For example, ADC320may convert analog signals, received from the set of sensing elements310, into digital signals to be processed by DSP330. ADC320may provide the digital signals to DSP330. In some implementations, magnetic sensor220may include one or more ADCs320.

DSP330may include a digital signal processing device or a collection of digital signal processing devices. In some implementations, DSP330may receive digital signals from ADC320and may process the digital signals to form output signals (e.g., destined for controller225as shown inFIG. 2A), such as output signals associated with determining the rotation angle of magnet215rotating with a rotatable object.

Optional memory element340may include a read only memory (ROM) (e.g., an EEPROM), a random access memory (RAM), and/or another type of dynamic or static storage device (e.g., a flash memory, a magnetic memory, an optical memory, etc.) that stores information and/or instructions for use by magnetic sensor220. In some implementations, optional memory element340may store information associated with processing performed by DSP330. Additionally, or alternatively, optional memory element340may store configurational values or parameters for the set of sensing elements310and/or information for one or more other elements of magnetic sensor220, such as ADC320or digital interface350.

Digital interface350may include an interface via which magnetic sensor220may receive and/or provide information from and/or to another device, such as controller225(seeFIG. 2A). For example, digital interface350may provide the output signal, determined by DSP330, to controller225and may further receive information from the controller225.

The number and arrangement of elements shown inFIG. 3are provided as an example. In practice, magnetic sensor220may include additional elements, fewer elements, different elements, or differently arranged elements than those shown inFIG. 3. Additionally, or alternatively, a set of elements (e.g., one or more elements) of magnetic sensor220may perform one or more functions described as being performed by another set of elements of magnetic sensor220.

FIGS. 4A-4Eare diagrams associated with an example implementation of the magnetic sensor system described herein.FIGS. 4A-4Eare associated with an example simulation400of the magnetic sensor system described herein. For the purposes of example simulation400, object205may be positioned in one of five tilt positions (e.g., T0, Tx1, Tx2, Ty1, and Ty2, where each of Tx1, Tx2, Ty1, and Ty2is approximately 5° tilt from T0), one of two linear positions (e.g., Pz1and Pz2), and/or one of 32 rotational positions (e.g., R1through R32), as described above. Here, assume that 161 states of object205are of interest in the given application, as described above with regard toFIG. 2A. Further, magnet215is a diametrally magnetized 3 mm cube-shaped magnet with a residual induction of 1000 mT that is arranged at a distance doof 0.876 mm from axis of rotation212, a distance dmof 12.6 mm from center of tilt210(e.g., in order to provide a tilt displacement of magnet215that is at least 1 mm), and with a magnet angle θMof 57°. Finally, magnetic sensor220is centered on axis of rotation212with an air gap distance daof 1.5 mm (e.g., when object205is not tilted).

FIG. 4Ais an example graphical representation showing states of object205mapped in a three-dimensional magnetic space. InFIG. 4A, each ring of symbols corresponds to a different tilt position, and each symbol on each ring corresponds to a different rotational position. For example, as shown, the ring including the black squares corresponds to tilt position T0, and each black square corresponds to one of the 32 possible rotational positions of object205while at tilt position T0. As further shown, the ring including the white circular markers corresponds to tilt position Tx1, and each marker corresponds to one of the 32 possible rotational positions of object205while at tilt position Tx1. The ring including the black circular markers corresponds to tilt position Tx2, and each marker corresponds to one of the 32 possible rotational positions of object205while at tilt position Tx2. As further shown, the ring including the white triangular corresponds to tilt position Ty1, and each marker corresponds to one of the 32 possible rotational positions of object205while at tilt position Ty1. The ring including the white square markers corresponds to tilt position Ty2, and each marker corresponds to one of the 32 possible rotational positions of object205while at tilt position Ty2.

InFIG. 4A, each of 160 possible states of object205when object205is not in the pushed position (e.g., any of 32 rotational positions at any of five tilt positions, when object205is in linear position Pz1) is represented by a different point in the three-dimensional magnetic space, where each point is defined by a magnetic field strength in the x-direction, the y-direction, and the z-direction, as shown. Thus, each state of object205may be mapped to a different set of magnetic field strengths. InFIG. 4A, a given point is separated from every other point by at least approximately 9.3 mT in the magnetic space, which is sufficient magnetic state separation to allow for reliable determination of the state of object205. In some implementations, sufficient magnetic state separation may be similarly achieved even when object205is positioned in a greater number of rotational positions (i.e., the minimum separation may be less than 9.3 mT, such as separation of approximately 1 mT or more). For example, if object205was capable of being positioned in 44 (e.g., rather than 32) rotational positions in a similar arrangement, then each of 220 possible states (e.g., 160 possible states plus 60 additional possible states resulting from the additional rotational positions) a given point is separated from every other point by at least approximately 6.3 mT in the magnetic space, which may be sufficient magnetic state separation to allow for reliable determination of the state of object205.

FIGS. 4B, 4C, and 4Dare example graphical representations of one-dimensional magnetic spaces, corresponding toFIG. 4A, for the magnetic field strengths in the x-direction, the y-direction, and the z-direction, respectively.

FIG. 4Eis associated with an experimental result450of the simulated magnetic sensor system associated with example simulation400. As shown inFIG. 4E, experimental result450closes matches example simulation400ofFIG. 4A.

Notably, the magnetic spaces described above do not include a representation of a sensed magnetic field when object205is in the pushed position (e.g., when object205is in position Pz2). However, when object205is in the pushed position, a strength of the z-component of the magnetic field at magnetic sensor220may be increased as compared to when object205is not in the pushed position (e.g., since the air gap between magnetic sensor220and magnet215may be decreased). In such a case, magnetic sensor220may determine that object205is in the pushed position based on determining that the z-component of the magnetic field satisfies a push-button threshold (e.g., is at or above a particular magnetic field strength), where the push-button threshold is high enough that the push-button threshold would not be satisfied when object205is not in the pushed position. In some implementations, magnetic sensor220may first determine whether object205is in the pushed position (e.g., based on the push-button threshold) and, if not, may determine the state based on mapping information associated with other possible positions.

As indicated above,FIGS. 4A-4Eare provided merely as examples. Other examples are possible and may differ from what was described with regard toFIGS. 4A-4E.

FIG. 5is a flow chart of an example process500for determining a state of object205using the magnetic sensor system described herein. In some implementations, one or more process blocks ofFIG. 5may be performed by magnetic sensor220. In some implementations, one or more process blocks ofFIG. 5may be performed by another device or a group of devices separate from or including magnetic sensor220, such as controller225.

As shown inFIG. 5, process500may include sensing components of a magnetic field generated by a magnet, where the magnet is connected to an object capable of being positioned with respect to multiple degrees of freedom (block510). For example, magnetic sensor220may sense components (e.g., including an x-component, a y-component, and a z-component) of a magnetic field generated by magnet215, where magnet215is connected to object205capable of being positioned with respect to multiple degrees of freedom, as described above.

As further shown inFIG. 5, process500may include determining, based on the components of the magnetic field, a state of the object with respect to the multiple degrees of freedom (block520). For example, magnetic sensor220may determine, based on the components of the magnetic field, a state of object205with respect to the multiple degrees of freedom.

In some implementations, magnetic sensor220may determine the state of object205based on a push-button threshold and/or mapping information configured on magnetic sensor220. For example, assume that object205may be in the pushed position or the non-pushed position, and that, while in the non-pushed position, object205may be in one of multiple tilt positions and one of multiple rotational positions (assume that tilt position and rotational position are not of interest while object205is in the pushed position). In this example, magnetic sensor220may compare the amplitude of the magnetic field to the push-button threshold. Here, if the amplitude of the magnetic field satisfies the push-button threshold (e.g., if the value of the amplitude is greater than or equal to the push-button threshold), then magnetic sensor220may determine the state of object205as being in the pushed position.

Alternatively, if the amplitude of the magnetic field does not satisfy the push-button threshold (e.g., if the value of the amplitude is less than the push-button threshold), then magnetic sensor220may determine that object205is not in the pushed position (i.e., that push-button is not enabled). Magnetic sensor220may then compare the components of the magnetic field to mapping information that associates sets of magnetic field strengths with particular states of object205, and may determine the state of object205based on identifying a set of magnetic field strengths that matches the components of the magnetic field, as described above.

As another example, assume that object205may be in the pushed position or the non-pushed position, and that, while in either the pushed position or the non-pushed position, object205may be in one of multiple tilt positions and one of multiple rotational positions (assume that tilt position and rotational position are of interest while object205is in the pushed position). In this example, magnetic sensor220may compare the components of the magnetic field to mapping information that associates sets of magnetic field strengths with particular states of object205, and may determine the state of object205based on identifying a set of magnetic field strengths that matches the components of the magnetic field, as described above.

As further shown inFIG. 5, process500may include providing information associated with the state of the object (block530). For example, magnetic sensor220may provide information associated with the state of object205.

In some implementations, the information associated with the state of object205may include information that identifies the state of object205, information that identifies magnetic field strengths of one or more sensed components of the magnetic field, information that identifies magnetic sensor220, and/or the like.

In some implementations, magnetic sensor220may provide the information associated with the state of object205to controller225(e.g., such that a system may be controlled based on the state of object205).

Implementations described herein provide a sensor system, including a single magnetic sensor and a single magnet, that is capable of detecting a state of an object with respect to multiple (e.g., four) degrees of freedom, such as a tilt with respect to a first direction, a tilt with respect to a second direction, a position along a third direction, and a rotational position. Since a single magnetic sensor and a single magnet are used, the sensor system described herein has a reduced complexity and/or a reduced cost (e.g., as compared to an implementation that uses multiple sensor systems to detect the state of the object). Moreover, the sensor system described herein provides for absolute encoding of the state of the object, thereby reducing complexity and/or increasing reliability of detecting the state of the object. Further, due to the use of magnetic sensing principles, the sensor system described herein has an increased lifetime (e.g., due to contact-free, and thus wear-free, operation), an increased potential for miniaturization, and an increased robustness against, for example, temperature and dirt.