Methods and apparatuses for providing a haptic output signal to a haptic actuator

1. A controller for providing a haptic output signal to a haptic actuator, the controller comprising:

an input configured to receive a force sensor signal from at least one force sensor; and

a haptic output module configured to generate a haptic output signal for output to a haptic actuator; wherein the haptic output module is configured to:

responsive to determining that the force sensor signal indicates that a force level applied to the at least one force sensor exceeds a first threshold, trigger output of the haptic output signal;

during output of the haptic output signal, adjust the haptic output signal based on the force sensor signal;

compare the force level that the force sensor signal indicates is being applied to the at least one force sensor to a plurality of threshold values;

adjust the haptic output signal based on the comparison;

adjust the haptic output signal responsive to the force sensor signal indicating that the force level applied to the at least one force sensor exceeds the first threshold and exceeds a second threshold higher than the first threshold; and

adjust the haptic output signal based on a length of time between the force sensor signal indicating that the force level exceeds the first threshold and the force sensor signal indicating that the force level exceeds the second threshold.

2. The controller of claim 1 wherein the haptic output module is configured to:

responsive to determining that the force sensor signal indicates that the force level applied to the at least one force sensor exceeds the first threshold, select a first stored haptic signal representation from a plurality of stored haptic signal representations based on the first threshold; and

generate the haptic output signal based on the first stored haptic signal representation.

3. The controller of claim 2 wherein the haptic output module is configured to adjust the haptic output signal by:

selecting a second stored haptic signal representation, and

adjusting the haptic output signal such that the haptic output signal is generated based on the second stored haptic signal representation.

4. The controller of claim 1 wherein, the haptic output module is configured to adjust one or more of an amplitude, acceleration or duration of the haptic output signal based on the force sensor signal.

5. The controller of claim 1 wherein the haptic output module is configured to adjust the haptic output signal based on at least one of an amplitude, rate of change and/or duration of the force sensor signal.

6. The controller of claim 1 wherein the controller forms part of a device, and wherein the controller is configured to receive an indication of an application running on the device, and wherein the haptic output module is configured to adjust the haptic output signal based on the indication.

7. The controller of claim 1 wherein the haptic output module is configured to:

determine a user action based on the force sensor signal, and

adjust the haptic output signal based on the user action.

8. The controller of claim 7 wherein the user action comprises one or more of: a button press, a button release and a button hold.

9. The controller of claim 1 wherein the haptic output signal comprises a pulse-width modulated signal.

10. A method for providing a haptic output signal to a haptic actuator, the method comprising:

receiving a force sensor signal from at least one force sensor;

responsive to determining that the force sensor signal indicates that a force level applied to the at least one force sensor exceeds a first threshold, triggering output of a haptic output signal;

during output of the haptic output signal, adjusting the haptic output signal based on the force sensor signal;

comparing the force level that the force sensor signal indicates is being applied to the at least one force sensor to a plurality of threshold values;

adjusting the haptic output signal based on the comparison;

adjusting the haptic output signal based on the comparison comprises adjusting the haptic output signal responsive to the force sensor signal indicating that the force level applied to the at least one force sensor exceeds the first threshold and exceeds a second threshold higher than the first threshold; and

adjusting the haptic output signal based on the comparison comprises adjusting the haptic output signal based on a length of time between the force sensor signal indicating that the force level exceeds the first threshold and the force sensor signal indicating that the force level exceeds the second threshold.

11. The method of claim 10 further comprising:

responsive to determining that the force sensor signal indicates that the force level applied to the at least one force sensor exceeds the first threshold, selecting a first stored haptic signal representation from a plurality of stored haptic signal representations based on the first threshold; and

generating the haptic output signal based on the first stored haptic signal representation.

12. The method of claim 11 wherein the step of adjusting the haptic output signal comprises:

selecting a second stored haptic signal representation, and

adjusting the haptic output signal such that the haptic output signal is generated based on the second stored haptic signal representation.

13. The method of claim 10 wherein, the step of adjusting comprises adjusting one or more of an amplitude, acceleration or duration of the haptic output signal based on the force sensor signal.

14. The method of claim 10 wherein step of adjusting comprises adjusting the haptic output signal based on at least one of an amplitude, rate of change and/or duration of the force sensor signal.

15. The method of claim 10 further comprising receiving an indication of an application running on a device, and adjusting the haptic output signal based on the indication.

16. The method of claim 10 further comprising:

determining a user action based on the force sensor signal, and

adjusting the haptic output signal based on the user action.

17. The method of claim 16 wherein the user action comprises one or more of: a button press, a button release and a button hold.

18. The method of claim 10 wherein the haptic output signal comprises a pulse-width modulated signal.

19. An integrated circuit comprising a controller for providing a haptic output signal to a haptic transducer, the controller comprising:

an input configured to receive a force sensor signal from at least one force sensor;

a haptic output module configured to generate a haptic output signal for output to a haptic actuator; wherein the haptic output module is configured to:

responsive to determining that the force sensor signal indicates that a force level applied to the at least one force sensor exceeds a first threshold, trigger output of the haptic output signal;

during output of the haptic output signal, adjust the haptic output signal based on the force sensor signal;

compare the force level that the force sensor signal indicates is being applied to the at least one force sensor to a plurality of threshold values;

adjust the haptic output signal based on the comparison;

adjust the haptic output signal responsive to the force sensor signal indicating that the force level applied to the at least one force sensor exceeds the first threshold and exceeds a second threshold higher than the first threshold; and

adjust the haptic output signal based on a length of time between the force sensor signal indicating that the force level exceeds the first threshold and the force sensor signal indicating that the force level exceeds the second threshold.

20. A device comprising:

at least one force sensor;

a haptic transducer; and

a controller for providing a haptic output signal to a haptic transducer the controller comprising:

an input configured to receive a force sensor signal from the at least one force sensor,

a haptic output module configured to generate a haptic output signal for output to the haptic transducer; wherein the haptic output module is configured to:

responsive to determining that the force sensor signal indicates that a force level applied to the at least one force sensor exceeds a first threshold, trigger output of the haptic output signal;

during output of the haptic output signal, adjust the haptic output signal based on the force sensor signal;

compare the force level that the force sensor signal indicates is being applied to the at least one force sensor to a plurality of threshold values;

adjust the haptic output signal based on the comparison;

adjust the haptic output signal responsive to the force sensor signal indicating that the force level applied to the at least one force sensor exceeds the first threshold and exceeds a second threshold higher than the first threshold; and

adjust the haptic output signal based on a length of time between the force sensor signal indicating that the force level exceeds the first threshold and the force sensor signal indicating that the force level exceeds the second threshold.

21. The device of claim 20 wherein the at least one force sensor comprises one or more of:

a capacitive displacement sensor, an inductive force sensor, a strain gauge, a piezoelectric force sensor, a force sensing resistor, a piezoresistive force sensor, a thin film force sensor, and/or a quantum tunneling composite based force sensor.

22. The device of claim 20 wherein the haptic transducer comprises a Linear Resonant Actuator, LRA.