It’s a Wrap for This Smart Ring’s Display

Everyone seems to be enraptured by their phone these days because of the productivity, connectivity, and entertainment that this little device offers us wherever we may roam. But is the little rectangle that we carry around in our pockets really the future of mobile computing? Wearable devices would seem to have an advantage over phones because they always come along for the ride by default. Moreover, significant progress has been made in this area recently with the release of new smart glasses and smartwatches.

But a group led by researchers at Penn State University thinks the future of mobile computing should fit on your little finger. The tiny size of smart rings allows them to transparently integrate into our daily lives, but it also leads to a number of limitations. Outputs, for example, are usually limited to either vibrations or integration with a phone. So to make these devices more capable, the team developed what they call VisRing, a smart ring with a display that completely encircles it.

Unlike existing smart rings that mostly serve as passive health trackers, VisRing includes an OLED display that is both flexible and surprisingly high-resolution for its size. This 160x32-pixel grayscale display can bend around the user’s finger, covering 270 to 360 degrees depending on finger size. At just 6.6 grams and costing roughly $35 to produce, the ring balances low weight and affordability while enabling capabilities that have so far been limited to much larger wearables like watches.

Inside the ring are multiple sensors, including an inertial measurement unit for gesture detection, a photoplethysmograph for measuring heart rate, a temperature sensor, Bluetooth for connectivity, and of course, the microcontroller that drives the device. The integration of these elements in such a small form factor was a significant engineering challenge, but some might say that it was not entirely a success. VisRing packs in a lot of tech, but it is also quite large.

To show what’s possible, the team created a software library for what they call “nano visualizations.” These are graphics specifically designed to fit on tiny, curved displays. The visualizations include line plots, bar charts, progress indicators, and animated icons, all optimized for readability at a glance.

The researchers demonstrated three applications built on the platform. The first is message delivery, where notifications arrive from a paired smartphone via Bluetooth. The ring lights up with an icon, then shows a short animated preview of the message content. The second application is time display, which uses gesture recognition to wake the ring when the wearer raises their hand to check the time. A large, legible digital clock appears, styled for easy reading. The third is health monitoring, which leverages the built-in photoplethysmography sensor. Here, VisRing can capture a raw waveform of blood flow through the finger and calculate heart rate in real time, displaying both the data and the derived beats-per-minute measurement directly on its screen.

With some improvements like a low-power e-ink display for extended battery life and enhanced privacy features to prevent shoulder-surfing, it’s easy to imagine a ring like this evolving into a mainstream platform. But as it stands today, VisRing is likely too large and too limited to peel people’s eyes away from their phones.