Bend angle sensing mechanism for wearable device
A wearable device to be worn on a body part includes a magnetic field generator, a magnetic field sensor, and a controller. The controller instructs the magnetic field generator to generate a magnetic field, instructs magnetic field sensor to measure a sensor signal, and to determine a position of the body part based on the measured sensor signal. The magnetic field sensor can include multiple sensor elements with known or solved positions relative to one another. The wearable device can be a glove. The controller may determine a bend angle of a finger or an angle between two fingers.
1. A wearable device comprising:
a plurality of magnetic field generators coupled to the wearable device, wherein the wearable device is configured to be worn on a body part of a user;
a corresponding one or more magnetic field sensors coupled to the wearable device; and
a controller configured to:
instruct each magnetic field generator to generate a magnetic field at a different frequency from other magnetic field generators,
instruct each corresponding magnetic field sensor to measure one or more sensor signals, and
determine spatial vectors representing relative position for each magnetic field generator and each corresponding magnetic field sensor based on the one or more sensor signals.
2. The wearable device of claim 1 , wherein at least one magnetic field sensor comprises a plurality of sensing elements with known or solved positions relative to one another.
3. The wearable device of claim 2 , wherein the magnetic field sensor comprises four sensing elements.
4. The wearable device of claim 1 , wherein the wearable device is a glove.
5. The wearable device of claim 4 , wherein at least one magnetic field generator is coupled to a known position on a first finger and at least one corresponding magnetic field sensor is coupled to a known position on a second finger, and the controller is further configured to determine a lateral angular separation between the first finger and the second finger based on the spatial vectors.
6. The wearable device of claim 4 , wherein at least one magnetic field generator is coupled to a first known position on a finger and at least one corresponding magnetic field sensor is coupled to a second known position on the finger, and the controller is further configured to determine a bend angle of the finger based on the spatial vectors.
7. The wearable device of claim 1 , wherein at least one magnetic field generator generates a magnetic field that propagates to at least one corresponding magnetic field sensor through an ambient environment.
8. The wearable device of claim 1 , wherein at least one magnetic field generator generates a magnetic field that propagates to at least one corresponding magnetic field sensor through a controlled medium.
9. The wearable device of claim 1 , wherein at least one magnetic field generator comprises a plurality of generating elements.
10. The wearable device of claim 1 , further comprising one or more sensing elements including at least one of a Hall effect sensor, a ferromagnetic lensing sensor, and a force sensor.
11. The wearable device of claim 10 , wherein the one or more sensing elements is configured to calibrate data from the one or more magnetic field sensors.
12. A method comprising:
generating, by each magnetic field generator of a plurality of magnetic field generators, a magnetic field at a different frequency from other magnetic field generators, wherein the magnetic field generators are coupled to a wearable device and the wearable device is configured to be worn on a body part of a user;
measuring, by one or more corresponding magnetic field sensors coupled to the wearable device, one or more sensor signals; and
determining, by a controller, spatial vectors representing relative position for each magnetic field generator and each corresponding magnetic field sensor based on the one or more sensor signals.
13. The method of claim 12 , wherein at least one magnetic field sensor comprises a plurality of sensing elements with known or solved positions relative to one another.
14. The method of claim 12 , wherein the wearable device is a glove.
15. The method of claim 14 , wherein at least one magnetic field generator is coupled to a known position on a first finger and at least one corresponding magnetic field sensor is coupled to a known position on a second finger, and the method further comprises determining a lateral angular separation between the first finger and the second finger based on the spatial vectors.
16. The method of claim 14 , wherein at least one magnetic field generator is coupled to a first known position on a finger and at least one corresponding magnetic field sensor is coupled to a second known position on the finger, and the method further comprises determining a bend angle of the finger based on the spatial vectors.
17. The method of claim 12 , wherein at least one magnetic field generator generates a magnetic field that propagates to at least one corresponding magnetic field sensor through an ambient environment.
18. The method of claim 12 , wherein at least one magnetic field generator generates a magnetic field that propagates to at least one corresponding magnetic field sensor through a controlled medium.
19. The method of claim 12 , wherein at least one magnetic field generator comprises a plurality of generating elements.
20. The method of claim 12 , further comprising one or more sensing elements including at least one of a Hall effect sensor, a ferromagnetic lensing sensor, and a force sensor and the method further comprises calibrating data from the one or more magnetic field sensors with the one or more sensing elements.