Voice assistant devices

1. A voice assistant device to receive an audio command, the device comprising:

an input to receive data defining an audio command; and

processing circuitry to perform an operation defined by the audio command responsive to an activation of the voice assistant device;

wherein the activation comprises determining presence of an activation source within an activation region from one or more sensors, the voice assistant device configured to enter a restricted mode responsive to a determination that the activation source is not within the activation region; and

wherein, when the voice assistant device is in the restricted mode, responsive to receiving the audio command the voice assistant device is configured to request a passphrase from a source of the audio command, and responsive to receiving a correct passphrase from the source of the audio command, the voice assistant device is configured to perform the operation defined by the audio command.

2. A voice assistant device as claimed in claim 1 , wherein the activation source comprises a user or a device controllable by the user.

3. A voice assistant device as claimed in claim 1 , wherein the activation further comprises determining presence of the activation source in combination with receipt of an audio activation via the input.

4. A voice assistant device as claimed in claim 1 , wherein the activation further comprises determining if both the audio activation and the presence are associated with the same activation source, and the activation is responsive to both the audio activation and presence resulting from the same activation source.

5. A voice assistant device as claimed in claim 1 , wherein at least one of the one or more sensors is integral to the voice assistant device and the activation further comprises receiving data defining presence of the activation source within the activation region.

6. A voice assistant device as claimed in claim 1 , wherein at least one of the one or more sensors are remote to the voice assistant device and the activation further comprises receiving a communication from the remote sensor comprising presence data defining presence of the activation source within the activation region.

7. A voice assistant device as claimed in claim 6 , wherein the one or more sensors to provide the activation are from a group of devices assigned to the activation region.

8. A voice assistant device as claimed in claim 7 , wherein the voice assistant device is configured to communicate with a remote service to identify and determine the one or more sensors from the group of devices to provide the activation.

9. A voice assistant device as claimed in claim 1 , wherein the activation source comprises at least one of the one or more sensors.

10. A voice assistant device as claimed in claim 1 , wherein the activation is responsive to detection of the presence of the activation source via one or more characteristics of the activation source.

11. A voice assistant device as claimed in claim 1 , wherein the activation further comprises detecting presence of a defined activation source.

12. A voice assistant device as claimed in claim 11 , wherein responsive to determining the defined activation source is absent from the activation region the voice assistant device is inhibited from activating for any other activation source.

13. A voice assistant device as claimed in claim 1 , wherein responsive to receiving a plurality of the same said audio command within a predetermined time window, the voice assistant device is configured to ignore repeated requests to perform the same operation defined by the audio command or query if the same operation should be repeated.

14. A voice assistant device as claimed in claim 1 , wherein the input comprises a communication input to receive a communication from a secondary audio receiving device to receive and communicate the audio command to the voice assistant device.

15. A voice assistant device as claimed in claim 1 , wherein the audio command comprises a spoken command or is initiated by a user.

16. A voice assistant device as claimed in claim 1 , wherein the activation comprises determining physical presence of the activation source.

17. A system comprising a plurality of audio receiving devices to receive audio commands, the audio receiving devices distributable about a plurality of regions within an environment; and at least one voice assistant device according to claim 14 capable of communication with at least a subset of the plurality of audio receiving devices to receive voice commands from audio receiving devices, wherein responsive to receiving a voice command the voice assistant device is configured to request a passphrase from a source of the voice command, and responsive to receiving a correct passphrase from the source of the voice command, the voice assistant device is configured to perform the operation defined by the voice command.

18. A computer-implemented method to process an audio command, the method comprising:

receiving, at a voice assistant device, an audio command;

determining presence of an activation source within an operational region for the voice assistant device;

entering a restricted mode responsive to a determination that the activation source is not within the operational region;

when the voice assistant device is in the restricted mode, requesting a passphrase from a source of the audio command in response to receiving the audio command; and

performing, at the voice assistant device, an operation defined by the audio command responsive to receiving a correct passphrase from the source of the audio command.