Visualization of heart-rate data for OLED smart rings
Date
2025
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Abstract
This bachelor’s thesis explores the visualization of heart rate (HR) data for organic light-emitting diode (OLED) smart rings, by evaluating the result visualizations of a prior design workshop and by conducting a pilot study investigating the detectability of a rectangle on a smart ring display. Visualizing information on relatively small displays is important for increasingly popular wearable devices (wearables), such as smartwatches and smart bracelets. The emergence of VisRing [36], a smart ring equipped with a curved OLED display, introduces new challenges due to the further reduction in display size and offers the potential to provide wearers with access to information, such as notifications or health data, analogous to other wearables. This work explores these challenges and potentials in two parts. In the first part, this work evaluates the result visualizations of a previously conducted smart ring ideation and expert focus group workshop held at the institute. For this, it analyzes HR visualizations based on the data and representation types, introduces a design space for HR visualizations on a smart ring, and provides a reference implementation. In the second part, this work presents a pilot study examining the detectability of a rectangle with varying brightness and height on the VisRing [36]. Six combinations of two brightness values and three rectangle heights were tested. The preliminary findings indicate a certain detection range of 23.22 mm (90 pixels) of the display circumference, equivalent to a central angle of ≈ 95.71° of the VisRing smart ring. Furthermore, the pilot study indicates higher detection rates for rectangles positioned near the center of the display, for brighter rectangles, and for rectangles of medium and large height. Altogether, this work provides an initial design space for HR visualizations on smart rings and presents a first preliminary attempt to address detectability at the outer edges of a smart ring display.