Magnetic sensing user interface device, methods, and apparatus
User interface devices with electromagnetic dipole arrays and associated magnetic sensors, control circuits, and processing elements for determining user actuation of the device are disclosed. In one embodiment a user interface device includes an electromagnetic dipole array coupled to an actuator, along with a three-axis magnetic sensor and control and processing elements for controlling driving currents to the dipole array and sensing and processing received magnetic field signals to determine movement or displacement of the actuator.
1. A user interface device, comprising:
an actuator element having a plurality of magnets;
a plurality of three-axis magnetic sensor elements, each associated with a corresponding magnet amongst the plurality of magnets, to sense the magnetic field components associated with displacements of the corresponding magnets in three orthogonal axes and provide magnetic sensor output data corresponding to the sensed magnetic field components;
a processing element communicatively coupled to the three-axis magnetic sensor elements to determine, based at least on the magnetic sensor output data, an estimated position or deformation of the actuator element from a released state; and
a memory to store a predefined magnetic field model, wherein the determined estimated position or deformation of the actuator element from the released state is further based on the predefined magnetic field model.
2. The device of claim 1 , wherein the plurality of magnets comprises cross-shaped electromagnets having a pair of dipole elements on orthogonal prongs of the cross shape.
3. The device of claim 1 , wherein the predefined magnetic field model is a closed form equation.
4. The device of claim 1 , wherein the output signal includes data defining the estimated position of the actuator element relative to the released state.
5. A user interface device, comprising:
an actuator element having a plurality of magnets;
a plurality of three-axis magnetic sensor elements, each associated with a corresponding magnet amongst the plurality of magnets, to sense the magnetic field components associated with displacements of the corresponding magnets in three orthogonal axes and provide magnetic sensor output data corresponding to the sensed magnetic field components; and
a processing element communicatively coupled to the three-axis magnetic sensor elements to determine, based at least on the magnetic sensor output data, an estimated position or deformation of the actuator element from a released state;
wherein the output signal is further based upon a reference position determined as an offset from the released position.
6. The device of claim 5 , wherein the offset is a function of temperature and the estimated position is adjusted responsive to a temperature measurement.
7. The device of claim 1 , wherein the determined estimated position or deformation of the actuator element from the released state is provided as an output signal to an electronic device coupled to the user interface device.
8. The device of claim 1 , wherein the plurality of three-axis magnetic sensor elements include four three-axis magnetic sensor elements and the plurality of magnets include four magnets, each corresponding to one of the plurality of three-axis magnetic sensor elements.
9. The device of claim 1 , wherein the plurality of magnets include one or more cylindrical magnets.
10. The device of claim 1 , further comprising a base and a plurality of springs disposed between the base and the actuator element.
11. A user interface device, comprising:
an actuator element having a plurality of magnets;
a plurality of three-axis magnetic sensor elements, each associated with a corresponding magnet amongst the plurality of magnets, to sense the magnetic field components associated with displacements of the corresponding magnets in three orthogonal axes and provide magnetic sensor output data corresponding to the sensed magnetic field components;
a base and a plurality of springs disposed between the base and the actuator element;
a processing element communicatively coupled to the three-axis magnetic sensor elements to determine, based at least on the magnetic sensor output data, an estimated position or deformation of the actuator element from a released state; and
a limiting component to limit movement of the actuator element relative to the base.
12. A user interface device, comprising:
an actuator element having a plurality of magnets;
a plurality of three-axis magnetic sensor elements, each associated with a corresponding magnet amongst the plurality of magnets, to sense the magnetic field components associated with displacements of the corresponding magnets in three orthogonal axes and provide magnetic sensor output data corresponding to the sensed magnetic field components;
a processing element communicatively coupled to the three-axis magnetic sensor elements to determine, based at least on the magnetic sensor output data, an estimated position or deformation of the actuator element from a released state; and
a plurality of switches disposed in the actuator element and an elastomeric cover including switch bumps corresponding to ones the plurality of switches disposed over the actuator element.
13. The device of claim 12 , wherein one or more of the plurality of switches are electro-mechanical switches.
14. The device of claim 12 , wherein one or more of the plurality of switches are pressure sensitive variable resistance switching devices.