Smart Ring Startup Takes Different Path to Cardiovascular Sensing — Electrical Signals Instead of Light
- Mar 3
- 3 min read
Safyr's Vascular Impedance Mapping™ technology secures U.S. patent protection and Swiss engineering partnership as FDA clarifies wearable blood pressure guidance
Denver, CO — February 2026 — As the smart ring market races past $1.5 billion and FDA issues new guidance on wearable cardiovascular devices, a Colorado-based startup is betting that the industry's reliance on optical sensors is the wrong foundation for meaningful cardiovascular insight.
Promptus, Inc. today announced Safyr™, a smart ring platform built on Vascular Impedance Mapping™ (VIM™) — an electrical sensing approach that measures how signals travel through tissue as blood flows, rather than analyzing light reflected from the skin's surface.
The company also announced that its foundational U.S. patent has been allowed by the USPTO and that it has entered an engineering partnership with CSEM, a globally recognized Swiss research organization, to advance system development toward FDA submission.
Why electrical sensing matters
Most wearables today use photoplethysmography (PPG) — optical sensors that shine light through the skin. This approach has known limitations: sensitivity to skin tone, lighting conditions, and sensor positioning have challenged efforts to deliver consistent cardiovascular measurements across diverse users.
Safyr takes a fundamentally different approach. A circular array of miniature electrodes inside the ring sends small electrical signals around the finger. As blood moves through the digital arteries with each heartbeat, it changes the electrical properties of surrounding tissue. VIM captures these changes to map vascular dynamics directly.
"The current wearable landscape is dominated by readings from nearly identical optical sensors," said Christopher Franks, CEO and Co-Founder of Promptus. "Instead of seeking new insights from old sensors, we took a different approach."
Feasibility validated in human studies
Pilot studies in 37 adult volunteers demonstrated correlation between Safyr's ring-derived vascular signals and reference cuff-based blood pressure measurements — results that informed the company's engineering development and regulatory planning.
"The challenge isn't just building a sensor," said Benjamin Sanchez Terrones, PhD, CTO and Co-Founder. "It's building one that physicians can actually trust. That requires starting with clinical relevance, not adding it later."
Regulatory timing
The announcement comes as FDA has issued updated guidance on both general wellness products and cuffless blood pressure devices, signaling clearer expectations for development and clinical evaluation in this category.
Safyr's regulatory strategy is informed by existing 510(k) precedent in cuffless blood pressure monitoring, with clinical validation and FDA submission targeted for Q1 2028.
Key developments
U.S. Patent Allowed (February 2026): Core patent covering Vascular Impedance Mapping™ technology allowed by USPTO; issuance pending
CSEM Partnership (February 2026): Engineering collaboration with Swiss research organization to advance system architecture
Regulatory Strategy Defined (January 2026): Development roadmap aligned with FDA 510(k) pathway
Feasibility Validated (2025): Pilot human studies completed in 37 adult volunteers
Leadership
Safyr is led by a team with combined experience spanning 6 FDA 510(k) clearances, multiple granted patents, and decades of medical device commercialization:
Christopher Franks, CEO & Co-Founder 25+ years building technology companies; faculty, University of Colorado Denver Business School
Patrick McCain, COO & Co-Founder 16+ years in regulated medical devices; 6 FDA 510(k) clearances; devices used in 15,000+ patients
Benjamin Sanchez Terrones, PhD, CTO & Co-Founder Bioimpedance expert; Harvard PhD and postdoc; inventor of VIM technology
Media Contact
For additional information about Safyr™, Vascular Impedance Mapping™, or Promptus, media and industry partners are invited to connect directly with:
Christopher Franks, CEO & Co-Founder of Promptus
About Promptus
Promptus, Inc. is developing Safyr™, a smart ring platform using proprietary Vascular Impedance Mapping™ (VIM™) technology to capture cardiovascular-related physiological signals. The company is pursuing a phased approach: wellness applications today, FDA-cleared medical applications tomorrow.
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