A social robot to help reduce stress: NEFFY 2.0 from Brain City Berlin

Brain City Berlin

Can a robot help reduce stress? That is exactly what researchers at the Berlin University of Applied Sciences (BHT) are exploring. Prof. Dr. Ilona Buchem and her team have developed NEFFY 2.0, a haptic breathing companion that guides people intuitively through breathing exercises. The findings of a recent study have been published in the Proceedings of the ACM/IEEE International Conference on Human Robot Interaction HRI2026.

A robot that invites you to breathe

NEFFY 2.0 is a small robot with a face displayed on a screen. To use it, you place your hands on its shoulders and breathe in time with its movements: the shoulder area rises on the inhale, lowers on the exhale, and the head follows the same motion. "The idea is really that you sit as if you were facing another person who is also breathing and breathing along with you," explains Buchem. The display also serves as a dashboard, allowing users to select language, volume and exercise duration. Sessions of one, three or five minutes are available.

NEFFY was developed in the Communications Laboratory at BHT, in close collaboration with students from the Humanoid Robotics degree programme. "I find it genuinely fascinating to investigate how a robot can be built that helps people relax and reduce stress," says Buchem. The complexity of the project was apparent from the outset, spanning haptic interaction and technical design through to the facial expression on the display and the sounds used.

Study with refugees from Ukraine

In the current study, the research team compared the effect of NEFFY 2.0 with a purely audio-based breathing exercise. Fourteen adult refugees from Ukraine took part, in cooperation with Johannesstift Diakonie and the Berlin university network "Zukunft findet Stadt". Participants completed both exercises in alternating order.

The results favour the robot: the perceived reduction in stress was significantly stronger in the robot condition, and the effect size in the statistical analyses was correspondingly larger. Buchem explains why: "Through the haptic experience, it was easier for people to synchronise their own breathing rhythm with the robot than with audio guidance alone." With the audio version, many participants felt unsure whether they were breathing at the right pace. Although the sample size of 14 is statistically limited, qualitative feedback confirmed the effect. Particularly striking for Buchem: "Everyone responded very positively to the robot, and there were no incidents where we had to stop the exercise." The study was overseen by an ethics committee, and participants were free to stop at any point without explanation.

Alongside self-reported data, physiological measurements were taken for the first time: using a chest strap and a finger clip, the team recorded heart rate, heart rate variability, breathing frequency and skin conductance. A cluster analysis of the results identified three distinct breathing patterns. Buchem notes, however: "Stress is a complex concept. This combination of different factors is not as clear-cut as what you capture with a questionnaire." Larger datasets will be needed for more robust physiological conclusions.

Berlin as a research location: networks make the difference

The fact that NEFFY could be developed and tested in this way owes a great deal to the research environment of Brain City Berlin. Access to study participants came through Sunpark, a Diakonie care facility in Marienfelde and a partner in the "Zukunft findet Stadt" network. At the same time, the team collaborated with HTW Berlin, whose Fashion and Clothing Technology degree programme designed fabric covers for NEFFY, including a washable teddy bear suit that makes the robot feel more welcoming for older users.

The network goes further still: a new project funded by the Berlin Innovation Fund brings BHT together with the Protestant University of Applied Sciences Berlin, the Catholic University of Applied Sciences for Social Work, and HTW Berlin. NEFFY will serve as a "boundary object", a shared reference point through which students from nursing, technology and other disciplines can contribute different perspectives to the robot's development. "We want to see how students from different subject-related perspectives can influence NEFFY's further development," says Buchem.

Outlook: NEFFY 3.0 is on its way

The team is already working on the third version. Alongside an improved display and expanded multilingual support, animal-like design elements are being considered, as these tend to generate a great deal of warmth and affinity. Sensors are also planned that will enable feedback based on the user's own breathing rhythm. The guiding principle remains: "We want to keep the technology simple. We very often get feedback that it is precisely this simplicity and understated quality that makes it feel trustworthy."

In the long term, NEFFY is intended for use in hospitals, care facilities and with people in stressful life situations. The planned NEFFY 3.0 is also being supported by the "Zukunft findet Stadt" Innovation Fund, with the aim of gaining new insights into neighbourhood-based long-term care. Anyone interested in developing a business idea around NEFFY is welcome to get in touch with Prof. Dr. Ilona Buchem: buchem@bht-berlin.de.

For Brain City Berlin, NEFFY is a prime example of what can emerge when universities, care facilities and civil society partners work closely together: a research project that combines technological innovation with genuine social benefit, and strengthens Berlin's reputation as a location for human-centred, transdisciplinary research.

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