I am exploring haptic responses that could support regulation without requiring the traveller to look at a screen or interpret a complex notification. This paper interested me because the device does not simply buzz to attract attention. It delivers a slow, heartbeat-like tactile rhythm intended to influence arousal more passively.
This gives me another useful example of a wearable where the response itself is bodily and rhythmic.
It is also useful for my current biosensing questions because the rhythm is personalised using the wearer’s resting heart rate, but the system tested here is not continuously adapting to live physiology.
doppel is a wrist-worn wearable that produces a double, heartbeat-like tactile pulse against the inside of the wrist.
The device was designed to be discreet, on-demand and user-controlled.
In the commercial concept described in the paper, the wristband connects to a smartphone app. The user measures their resting heart rate and can choose the speed and intensity of the tactile rhythm in relation to that baseline.
The idea is based on entrainment: the possibility that external rhythms can influence bodily or emotional states.
For the calming condition tested in this study, the tactile heartbeat was deliberately set slower than the participant’s own resting heart rate.
Each participant completed a resting baseline while heart rate was measured.
The active device was then set to approximately 20% slower than that participant’s resting heart rate, with upper and lower limits imposed so that the rhythm did not feel unnaturally fast or slow.
The average tactile rhythm was around 58 beats per minute.
What I find interesting here is that the output is personalised using biodata, but only at the beginning.
The system does not keep reading the user’s heart rate and dynamically chase it. Instead, physiology is used to create an individual starting point for the tactile response.
That is a much simpler form of bioresponsive design than a continuously adaptive closed loop.
The study involved 52 adults, randomly assigned to two groups.
Twenty-five participants were in the active doppel condition and 27 were in the control condition.