May 24, 2024


French startup Circular claims to have created the world’s thinnest and lightest smart ring — as well as the first-ever to use haptic navigation.

The wearable, named the Circular Ring Slim, became available on pre-order today.

Weighing just 2 grams and measuring a mere 2.2 mm in thickness, the device packs big features into a tiny frame.

To analyse the user’s health, the ring assesses seven biometrics and 142 derived markers. These markers are captured by a suite of sensors.

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One is a simple surface temperature sensor. Another is a three-axis accelerometer count, which assesses activity and movement.

Then there are the sensors that apply PPG. It’s a much-needed acronym: PPG stands for photo-plethysmo-graphy — an optical technique that detects blood volume changes.

In the Circular Slim Ring, the PPG combines three different LED light wavelengths — green, red, and infrared — to capture numerous health vitals. These range from heart and respiratory rates to blood oxygen levels.

When night falls, the ring shifts to tracking signs of sleep quality, such as REM cycles and wake times. While the user dreams, the sensors also measure temperature variations. These are combined with other biometrics to probe immune systems and detect symptoms of illness.   

All readings are then transmitted to Kira+, Circular’s AI assistant, which turns the data into insights and advice. 

Circular is bullish about the system’s accuracy.

“The ring is used in many clinics and scientific studies,” Laurent Bsalis, the company’s founder and CEO, told TNW. “From the outset, we’re very focused on data accuracy and, for example, we’ve preferred not to show data that is hard to get, rather than showing fake data — unlike other competitors.”

The Circular Slim smart ring with green light flashing from the inside