Haptic keyboard system

1. A system for detecting touch inputs comprising:

a substrate;

a first inductor arranged on the substrate;

a first key:

defining a first key location; and

arranged over the substrate;

a first magnetic element:

defining a first magnetic polarity; and

configured to inductively couple to the first inductor responsive to force applied to the first key location; and

a controller configured to:

access electrical values from the first inductor; and

at a first time, in response to detecting a first change in electrical value at the first inductor:

trigger an oscillating voltage across the first inductor during a first haptic feedback cycle;

to induce alternating magnetic coupling between the first inductor and the first magnetic element; and

to oscillate the first key relative to the substrate;

wherein the first inductor comprises a set of planar coil traces, the set of planar coil traces comprising:

a first spiral trace:

arranged across a first layer of the substrate, below the first key; and

a second spiral trace:

arranged across a second layer of the substrate, below the first layer;

electrically coupled to the first spiral trace; and

cooperating with the first spiral trace to form a first loop of the first inductor.

2. The system of claim 1 , further comprising:

an array of inductors arranged on the substrate, the array of inductors comprising the first inductor; and

a set of keys:

defining a set of key locations;

arranged over the substrate aligned with the array of inductors;

comprising the first key; and

forming a first keyboard.

3. The system of claim 2 , wherein the controller is configured to:

at the first time, in response to detecting the first change in electrical value at the first inductor, register a first keystroke associated with the first key at a first key location in the set of key locations;

access electrical values from the array of inductors at a second time succeeding the first time; and

in response to detecting a second change in electrical value at a second inductor, in the array of inductors:

register a second keystroke associated with a second key:

at a second key location in the set of key locations; and

facing the second inductor; and

trigger a second oscillating voltage across the second inductor during a second haptic feedback cycle:

to induce alternating magnetic coupling between the second inductor and the second magnetic element; and

to oscillate the second key relative the substrate.

4. The system of claim 3 , wherein the controller is configured to initiate the

second haptic feedback cycle at the second inductor upon completion of the first haptic feedback cycle.

5. The system of claim 1 , wherein the controller is configured to:

access electrical values, from the first inductor, representing voltages across the first inductor;

detect the first change in electrical value comprising a first voltage of a first electric polarity across the first inductor at the first time;

register a first keystroke associated with the first key in response to detecting the first voltage of the first electrical polarity across the first inductor;

trigger the oscillating voltage across the first inductor during the first haptic feedback cycle in response to registering the first keystroke;

in response to detecting a second voltage of a second electrical polarity, opposite the first electrical polarity, across the first inductor at a second time succeeding the first time:

register release of the first keystroke; and

trigger a second oscillating voltage across the first inductor during a second haptic feedback cycle succeeding the first haptic feedback cycle.

6. The system of claim 5 , wherein the controller is configured to:

register the first keystroke associated with the first key in response to the first voltage exceeding a first threshold voltage;

trigger the oscillating voltage across the first inductor at a first frequency during the first haptic feedback cycle in response to registering the first keystroke; register release of the first keystroke in response to the second voltage exceeding a second threshold voltage less than the first threshold voltage; and

trigger the second oscillating voltage across the first inductor at a second frequency greater than the first frequency during the second haptic feedback cycle in response to registering release of the first keystroke.

7. The system of claim 1 , wherein the controller is configured to:

access electrical values, from the first inductor, representing current flow through the first inductor;

detect the first change in electrical value comprising a first current through the first inductor in a first direction at the first time;

register a first keystroke associated with the first key in response to detecting the first current moving through the first inductor in the first direction;

trigger the oscillating voltage across the first inductor during the first haptic feedback cycle in response to registering the first keystroke;

detect a second current through the first inductor in a second direction opposite the first direction at a second time succeeding the first time;

register release of the first keystroke in response to detecting the second current through the first inductor in the second direction; and

trigger a second oscillating voltage across the first inductor during a second haptic feedback cycle in response to registering release of the first keystroke.

8. The system of claim 1 :

wherein the first key comprises an elastic sublayer:

interposed between the substrate and the first magnetic element; and

configured to locally compress to enable movement of the first magnetic element toward the first inductor responsive to force applied to the first key; and

wherein the first magnetic element inductively couples to the first inductor and induces current flow in a first direction through the first inductor responsive to movement of the first magnetic element toward the first inductor.

9. The system of claim 1 :

further comprising an elastic sublayer arranged over the substrate; and

wherein the first key defines a first rigid key element:

coupled to the elastic sublayer opposite the substrate;

housing the first magnetic element; and

configured to compress the elastic sublayer to move the first magnetic element toward the inductor responsive to force applied to the first rigid key element, the first magnetic element inducing current flow through the first inductor.

10. The system of claim 1 , wherein the first key:

defines a key face;

comprises an elastic post:

extending opposite the key face toward the first inductor; and

retaining the first key element over the substrate;

houses the first magnetic element; and

is configured to compress against the substrate and to move the first magnetic element toward the first inductor responsive to force applied to the key face, the first magnetic element inducing current flow through the first inductor responsive to motion relative to the first inductor.

11. The system of claim 1 :

wherein the first spiral trace and the second spiral trace are coaxial about a primary axis of the inductor;

wherein the first magnetic element comprises:

a first magnet:

arranged over the first inductor;

offset from the primary axis of the first inductor; and

defining the first magnetic polarity facing the first inductor; and

a second magnet:

arranged over the first inductor;

offset from the primary axis of the first inductor opposite the first magnet; and

defining the first polarity facing away from the first inductor; and

wherein the controller is configured to trigger the oscillating voltage across the first inductor during the first haptic feedback cycle to induce alternating magnetic coupling between the first inductor, the first magnet, and the second magnet.

12. The system of claim 1 :

wherein the set of planar coil traces further comprises:

a third spiral trace:

arranged across the first layer of the substrate, adjacent the first spiral trace;

coiled in the second direction; and

electrically coupled the first spiral trace; and

a fourth spiral trace:

arranged across the second layer of the substrate, adjacent the second spiral trace;

coiled in the first direction;

electrically coupled to the third spiral trace;

cooperating with the third spiral trace to form a second loop of the first inductor defining a secondary axis parallel to and offset from a primary axis of the first loop of the first inductor;

wherein the first magnetic element comprises:

a first magnet:

arranged over the primary axis of the first loop of the first inductor; and

defining the first magnetic polarity facing the first inductor; and

a second magnet:

adjacent the first magnet;

arranged over the secondary axis of the second loop of the first inductor; and

defining the first magnetic polarity facing away from the first inductor; and

wherein the controller is configured to trigger the oscillating voltage across the first inductor during the first haptic feedback cycle to:

induce alternating magnetic coupling between the first magnet and the first loop of the first inductor; and

induce alternating magnetic coupling between the second magnet and the second loop of the first inductor.

13. The system of claim 1 :

wherein the first key comprises a first translucent region;

further comprising a first light element:

arranged on the substrate adjacent the first inductor;

facing the first key; and

configured to illuminate the first translucent region within the first key location.

14. A system for detecting touch inputs comprising:

a substrate comprising a set of drive and sense electrode pairs;

a first inductor arranged on the substrate;

a tactile layer arranged over the substrate;

a first magnetic element defining a first magnetic polarity facing the first inductor and configured to inductively couple the first inductor responsive to forces applied to the tactile layer; and

a controller configured to:

access a first set of electrical values from the set of drive and sense electrode pairs;

identify a force applied to the tactile layer based on the first set of electrical values;

access a second set of electrical values from the first inductor;

interpret a first force magnitude of the force applied to the tactile layer based on the second set of electrical values; and

at a first time, in response to the first force magnitude exceeding a threshold magnitude, trigger an oscillating voltage across the first inductor during a first haptic feedback cycle to induce alternating magnetic coupling between the first inductor and the first magnetic element and oscillate the tactile layer.

15. The system of claim 14 , wherein the controller is configured to:

access the second set of electrical values, from the first inductor, representing voltages across the first inductor;

interpret the first force magnitude based on a first voltage of a first electrical polarity across the first inductor; and

trigger the oscillating voltage across the first inductor during the haptic feedback cycle in response to the first voltage exceeding a threshold voltage.

16. The system of claim 14 , wherein the controller is configured to:

access the second set of electrical values representing a set of voltages across the first inductor;

interpret the force as a first touch input;

trigger the oscillating voltage across the first inductor during the first haptic feedback cycle in response to detecting a first voltage, in the set of voltages, of a first electrical polarity across the first inductor;

in response to detecting a second voltage in the set of voltages of a second electrical polarity, opposite the first electrical polarity, across the first inductor at a second time succeeding the first time:

register release of the first touch input; and

trigger a second oscillating voltage across the first inductor during a second haptic feedback cycle succeeding the first haptic feedback cycle.

17. The system of claim 16 , wherein the controller is configured to:

register the first touch input in response to the first voltage exceeding a first threshold voltage;

trigger the oscillating voltage across the first inductor at a first frequency during the first haptic feedback cycle in response to registering the first touch input;

register release of the first touch input in response to the second voltage exceeding a second threshold voltage less than the first threshold voltage; and

trigger the second oscillating voltage across the first inductor at a second frequency greater than the first frequency during the second haptic feedback cycle in response to registering release of the first touch input.

18. The system of claim 16 , wherein the controller is configured to:

register the first input on the touch sensor surface in response to a first electrical value, in the set of electrical values, of the first polarity exceeding a threshold value; and

register release of the first input from the touch sensor surface in response to detecting a second electrical value, in the set of electrical values, of a second polarity opposite the first polarity; and

in response to registering release of the first input from the touch sensor surface:

terminate the haptic feedback cycle;

cease alternating magnetic coupling; and

cease oscillation of the tactile layer.

19. A system for detecting touch inputs comprising:

a multi-layer inductor formed of a set of spiral traces arranged across a substrate;

a tactile layer:

arranged over the substrate; and

defining a touch sensor surface over the multi-layer inductor;

a magnetic element:

defining a first polarity facing the multi-layer inductor; and

configured to inductively couple to the multi-layer inductor responsive to application of force on the touch sensor surface; and

a controller configured to:

access a set of electrical values from the multi-layer inductor; and

detect a first input on the touch sensor surface based on the set of electrical values; and

in response to detecting the first input on the touch sensor surface, trigger an oscillating voltage across the multi-layer inductor during a haptic feedback cycle:

to induce alternating magnetic coupling between the multi-layer inductor and the magnetic element; and

to oscillate the tactile layer relative to the substrate;

wherein the first inductor comprises a set of planar coil traces, the set of planar coil traces comprising:

a first spiral trace:

arranged across a first layer of the substrate, below the first key; and

a second spiral trace:

arranged across a second layer of the substrate, below the first layer;

electrically coupled to the first spiral trace; and

cooperating with the first spiral trace to form a first loop of the first inductor.