Relax with Light and DeLight

Light is a common means of the ambient display because it is rich in parameters for presenting information but also has the ability to evoke moods and create immersive experiences. We started our explorations at the intersection of the lighting design, biofeedback, and relaxation. This led to a biofeedback lighting system named DeLight, through which we explored how the ambient light could be used as a medium to both present physiological information but also promotes relaxation.

Our initial idea of DeLight is to capture physiological data and represent the unobservable internal states of a person in the form of lighting in the environment. The concept of DeLight is not just an interface for biofeedback, but a lighting environment for relaxation training. Compared with on-screen numeric or graphic displays, the lighting interface allows the users to use biofeedback techniques with few restraints on the place of use. The average users (non-specialists) do not have to sit in front of a computer and stare at the screen, but they can perform relaxation practice in a living space or home environment.

DeLight system consists of three parts: a bio-sensing device, a biofeedback program, and an intelligent lighting system. DeLight lighting system consists of a center light and several ambient lights. The center light is a wireless portable lamp which can be placed anywhere and held by the users during the relaxation. The ambient lights refer to the lamps that are installed on the ceiling or placed on the floor, creating the ambiance of the indoor environment.


Breathing is a process of gas exchange, where we breathe in oxygen and breathe out carbon dioxide. With the DeLight system, as an individual inhale, the air is breathed into body and the heart rate increases, causing the brightness distribution transferred from the ambient lights to the center lights close to the body. Conversely, on exhale, the air is expelled from lungs, and accordingly, the brightness is transferred to the ambient lights far from the body.


With the user’s breathing becoming slow and deep, the IBI change in an approximate sinusoidal pattern, and accordingly, the brightness is ‘transferred’ between the center and ambient lights periodically.


Depending on the improvement of HRV, the light color changes from white to blue.

Yu, B., Hu, J., Funk, M. and Feijs, L., Delight: Lighting Biofeedback for Stress Management, Personal and Ubiquitous Computing, In Press, 2018.