Final Project Accomplishments: The pilot project focused on developing and validating BPClip, a low-cost, smartphone-based blood pressure monitoring device. The system uses a spring-loaded plastic clip and a smartphone’s camera and flash to perform oscillometric measurements at the fingertip, eliminating the need for traditional cuffs or calibration. The team successfully built the device, developed a companion app, and implemented a signal processing pipeline to convert video data into blood pressure readings. In a validation study with 29 participants, BPClip achieved mean absolute errors of 8.72 mmHg (systolic) and 5.49 mmHg (diastolic), demonstrating promising accuracy. A usability study with older adults revealed that while the device is generally operable, improvements are needed for users with limited dexterity or finger strength.

The project resulted in several significant outcomes, including a peer-reviewed publication in Scientific Reports, a provisional patent (now a PCT), and the formation of a startup, Billion Labs Inc., to commercialize the technology. The device’s estimated production cost is under $0.80 per unit, making it highly scalable and accessible for global health applications. The work received widespread media attention and was presented at multiple academic and industry venues. The BPClip represents a major step toward democratizing blood pressure monitoring, particularly in low-resource settings, by leveraging ubiquitous smartphone technology and low-cost hardware.

Initial Proposal Abstract: We aim to democratize blood pressure monitoring by converting the billions of smartphone cameras, even the cheapest ones, into blood pressure (BP) monitors with an ultra-low-cost plastic clip that can be produced for mere cents. More than 70% of persons aged 65 years and older had BPs meeting the definition of hypertension, yet hypertension control rates are lower among older persons. Older adults have additional challenges with advancing age including increasing multimorbidity and limitations that affect mobility, dexterity, vision and hearing.

Given the prevalence of uncontrolled hypertension and additional challenges in the older adult population, it is essential that measurement of BP be done easily and accurately, but at the same time usable by themselves with little to no training and can be operated with limited dexterity. The proposed invention leverages a similar scientific premise as oscillometry performed by standard BP cuffs, but instead measured at the finger.

The insight that enables our innovation is the use of computational imaging that combines a smartphone camera with a cheap plastic clip that uses a mechanical interface to create an image projection on the smartphone camera that encodes both the force applied to the finger and the pulse amplitude needed for calculating blood pressure. The proposed invention has the potential to become a new class of BP monitoring device available for public health studies and programs that is not only low-cost, but inherently compatible with mobile platforms to leverage connectivity for compatibility with systemwide records.