  Smart speakers are gaining popularity. However, such devices can put the
user's privacy at risk whenever hot-words are misinterpreted and voice data is
recorded without the user's consent. To mitigate such risks, smart speakers
provide privacy control mechanisms like the build-in mute button.
Unfortunately, previous work indicated that such mute buttons are rarely used.
In this paper, we present the Privacy Hat, a tangible device which can be
placed on the smart speaker to prevent the device from listening. We designed
the Privacy Hat based on the results of a focus group and developed a working
prototype. We hypothesize that the specific user experience of this physical
and tangible token makes the use of privacy-enhancing technology more graspable
for the user. As a consequence, we expect that the Privacy Hat nudges users to
more actively use privacy-enhancing features like the mute button. In addition,
we propose the Privacy Hat as a study tool as we hypothesize that the artifact
supports participants in reflecting their behaviour. We report on the concept,
the prototype and our preliminary results.
