Force-detecting input structure
An input mechanism, such as a crown, detects amounts of applied force. In various examples, an assembly including an input mechanism has an enclosure; a stem coupled to the enclosure such that the stem is rotatable, translatable, and transversely moveable with respect to the enclosure; a sensor, coupled between the stem and the housing, to which force is transferred when the stem moves with respect to the housing; and a processing unit coupled to the sensor. The processing unit is operable to determine a measurement of the force, based on a signal from the sensor.
1. An electronic device, comprising:
a housing;
a collar, coupled to the housing, comprising:
a moveable conductor; and
a conductive element; and
a crown, comprising:
a cap; and
a shaft positioned partially within an aperture defined by the collar and attached to the cap;
wherein:
the movable conductor and the conductive element are separated by a distance; and
movement of the shaft in response to an input force on the cap reduces the distance, thereby changing a capacitance between the moveable conductor and the conductive element.
2. The electronic device of claim 1 , further comprising a processing unit operative to determine an amount of force applied to the crown based on the change in capacitance.
3. The electronic device of claim 1 , further comprising silicone disposed within the distance.
4. The electronic device of claim 1 , wherein the conductive element comprises a flex circuit that extends through at least part of the collar into the housing.
5. The electronic device of claim 1 , wherein the collar comprises:
an inner core to which the conductive element is coupled; and
a compliant material disposed in the distance that couples the conductive element and the moveable conductor.
6. The electronic device of claim 1 , wherein the shaft is operable to move without changing the capacitance between the moveable conductor and the conductive element.
7. A crown assembly, comprising:
an enclosure;
a stem coupled to the enclosure, such that the stem is:
rotatable with respect to the enclosure;
translatable with respect to the enclosure; and
transversely moveable with respect to the enclosure;
a sensor, coupled between the stem and the enclosure, the stem configured to compress the sensor when the stem moves transversely with respect to the enclosure; and
a processing unit, coupled to the sensor, operable to determine a measurement of the force, based on a signal from the sensor.
8. The crown assembly of claim 7 , wherein the processing unit is operative to determine a direction in which the stem moves transversely.
9. The crown assembly of claim 7 , wherein the sensor comprises a strain gauge.
10. The crown assembly of claim 7 , wherein the sensor comprises:
a first conductor;
a second conductor; and
a dielectric separating the first and second conductors.
11. The crown assembly of claim 10 , wherein the dielectric comprises a compliant material.
12. The crown assembly of claim 7 , further comprising:
a collar coupled to the enclosure; wherein
the sensor couples the stem to the collar.
13. The crown assembly of claim 7 , further comprising a wireless transmission mechanism that wirelessly couples the processing unit and the sensor.
14. The crown assembly of claim 7 , further comprising:
an additional sensor coupled between the stem and the processing unit; wherein
the processing unit is operable to determine a measurement of a force that translates the stem, based on a signal from the additional sensor.
15. An electronic device, comprising:
a body;
a coupler positioned at least partially within the body;
a crown, connected to the coupler, and operable to move with respect to the body;
a capacitive sensor coupled to the crown, and configured to deform in response to a force being applied to the crown; and
a processing unit operable to ascertain an amount of the force based on a change in a capacitance of the capacitive sensor.
16. The electronic device of claim 15 , wherein the coupler includes the capacitive sensor.
17. The electronic device of claim 15 , wherein the capacitive sensor comprises:
a first capacitive element;
a second capacitive element; and
a compliant material positioned between the first and second capacitive elements; wherein
the compliant material:
extends between the coupler and the body; and
seals the coupler to the body.
18. The electronic device of claim 17 , wherein a change in proximity between the first and second capacitive elements is proportional to the amount of the force.
19. The electronic device of claim 15 , wherein the input mechanism moves transverse with respect to the body.
20. The electronic device of claim 15 , wherein a portion of the crown is operable to move closer to the body.