Cuff‑less, Clinically Accurate Blood‑Pressure Device in a Pocket‑Sized Keyfob

During CES 2021 in Lausanne, Switzerland, Leman Micro Devices (LMD) unveiled a pocket‑sized keyfob that delivers clinically accurate blood‑pressure readings and additional vital‑sign metrics directly to a smartphone via Bluetooth.

The keyfob is the outcome of a recent collaboration between LMD, Shanghai Minshi (a device designer and manufacturer), and WuQi (a Shanghai‑based Bluetooth technology provider). Beyond cuff‑less blood‑pressure measurement, the device accurately records SpO₂, respiration rate, pulse rate, and body temperature—all without calibration.

At its core is LMD’s patented V‑Sensor, complemented by a rechargeable battery and a compact WuQi chip that communicates via Bluetooth to a dedicated smartphone app. The circular form factor—5 cm in diameter and 2.5 cm deep—fits comfortably in the palm and can be secured to a keyring, worn at the neck, or slipped into a bag.

Developed across nine years of research, the V‑Sensor features a fingertip‑shaped cavity housing a MEMS pressure sensor encased in flexible resin. It also integrates an optical sensor, a temperature sensor, and LMD’s proprietary ASIC, which processes sensor data, powers the LEDs, and manages wireless communication.

To capture a blood‑pressure reading, the user gently presses the device between thumb and forefinger while following intuitive, game‑style prompts on the app. The V‑Sensor occludes the index‑finger arteries—mirroring the classic Riva‑Rocci cuff technique—then optically senses the balance pressure with its pulse‑oximeter. Within roughly 45 seconds, the app presents an absolute blood‑pressure value.

The Minshi keyfob incorporates LMD’s V‑Sensor, delivering clinically accurate measurements of blood pressure, SpO₂, respiration rate, pulse rate, and body temperature. (Image: Leman Micro Devices)

For contactless core‑temperature measurement, the user holds the module near the forehead; the app then records and displays the reading.

Headquartered in Lausanne—often dubbed the ‘Health Valley’ and adjacent to EPFL University—LMD specializes in medically accurate, mobile‑health technologies. The V‑Sensor and accompanying e‑Checkup app are engineered for seamless integration into smartphones, wearables, and other mobile devices, allowing consumers to track vital signs—including blood pressure, SpO₂, pulse, temperature, and respiration—with clinical precision.

The V‑Sensor represents the third generation of wearable trackers. While first‑generation devices count steps and second‑generation models monitor pulse, LMD’s technology elevates the standard by delivering medical‑grade accuracy. Accurate blood‑pressure measurement is vital, as hypertension—affecting over 10 million deaths annually—is often undetected yet treatable. The V‑Sensor eliminates calibration and obviates the need for conventional cuff‑based home monitors.

Chris Elliott, LMD co‑founder, said: “Our partnership with Shanghai Minshi and WuQi marks an exciting milestone that will bring the V‑Sensor into consumers’ hands this year, empowering them to manage their health more comprehensively than any other wearable on the market. V‑Sensor devices are the only wearable or smartphone platform capable of clinically accurate vital‑sign measurement, and we are thrilled to collaborate with outstanding partners to launch the first standalone Bluetooth‑enabled V‑Sensor product.”

Zhongwei Geng, CEO of Shanghai Minshi, added: “Collaborating with WuQi and LMD to develop the world’s first truly standalone miniature blood‑pressure and vital‑signs device is a major breakthrough. Its portability and ease of use—paired with a dedicated app—deliver unparalleled convenience for accurate, anytime‑anywhere blood‑pressure monitoring.”

>> This article was originally published on our sister site, EE Times Europe.

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