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Posts tagged: Wearables

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Macro photograph of finger skin showing the dense capillary network near the surface. The biological reason transmissive PPG works better at the fingertip than the wrist.

Sleep · Wearables

Why the Smart Ring Form Factor Is Better for Sleep Than the Wrist: A Physics Argument

The wrist is the worst place to measure heart rate during sleep. It is too thick for transmissive PPG, too prone to motion artifact, and too thermally unstable. The finger wins on every metric that matters for overnight biometrics.

James Hoffmann James Hoffmann
May 29, 2026 13 min read
A luxury ring display in a velvet case, the kind of presentation that signals a premium price before you ever see the numbers

Wearables

Oura Ring 5 Is $499. Here Is What Three Years Actually Costs.

Oura launched the Ring 5 at $499 with a mandatory subscription and a new AI coach fee. Over three years, the cheapest configuration totals $715. Here is the math, and why Pulsyn is building the alternative.

James Hoffmann James Hoffmann
May 29, 2026 12 min read
Thermal imaging of a human hand showing heat distribution. The kind of raw signal most smart rings average away

Sleep · On Device Ai · Wearables

What Skin Temperature Actually Tells You (And Why Most Rings Get It Wrong)

Skin temperature is a proxy for blood flow, circadian phase, and autonomic tone. Most smart rings average it into a single nightly number. We do not.

James Hoffmann James Hoffmann
May 28, 2026 14 min read
A medical pulse oximeter clipped to a fingertip, using transmissive light technology that consumer smart rings cannot replicate

Research, Explained · Wearables · Hrv

Why Your Smart Ring SpO2 Reading Is Probably a Guess

Consumer wearables run reflective PPG on body parts never designed for it. The FDA has scrutinized these monitors since 2022 for systematic bias. Smart rings compound the problem with clamp pressure and unvalidated algorithms.

James Hoffmann James Hoffmann
May 28, 2026 11 min read
A hardware workshop with tools and prototype components on a workbench

Wearables · Company News

A $500K Kickstarter Is the Most Honest Milestone in Hardware

Most hardware startups take VC money before they know if anyone wants their product. Pulsyn's $500K Kickstarter campaign is a demand test with no safety net.

James Hoffmann James Hoffmann
May 27, 2026 11 min read
Abstract digital privacy visualization representing encrypted health data that never leaves your device

Privacy · Wearables

Your Fertility Data Is Evidence Now

In a post-Dobbs United States, fertility data from wearables has entered criminal prosecutions. Oura stores cycle data on AWS. Whoop stores it on their own servers. Pulsyn stores it on your phone, encrypted, with no cloud account.

James Hoffmann James Hoffmann
May 27, 2026 13 min read
A gavel resting on a courtroom bench, representing how digital health data from fitness trackers is now routinely admitted as evidence in legal proceedings

Privacy · Wearables

Your Fitness Tracker Is Evidence: How Health Data Ends Up in Courtrooms and Divorce Filings

Your fitness tracker records everything. That data lives on someone else's server, and in at least one murder trial, it was the evidence that convicted the killer. Here's how health data ends up in courtrooms, divorce filings, and subpoenas — and why Pulsyn's local-first architecture makes the difference.

James Hoffmann James Hoffmann
May 26, 2026 13 min read
A customs inspection checkpoint at a border crossing — where Ultrahuman Ring Pro just cleared after months blocked by Oura patent disputes

Wearables

Ultrahuman Ring Pro Lands in the US at $479

Ultrahuman Ring Pro just cleared US customs after an Oura patent block and is selling at $479 with no subscription. That price validates Pulsyn's entire thesis: on-device health tracking should not cost more than a flagship smartphone.

James Hoffmann James Hoffmann
May 26, 2026 11 min read
A simple budget fitness tracker on a wrist, representing the low-cost wearable hardware that Pebble and independent smart ring makers are building

Wearables

Pebble's $75 Index 01 and the Great Smart Ring Divergence

The smart ring market is splitting into three species: premium health platforms, single-purpose tools, and subscription-hungry AI wrappers. Pebble's Index 01 proves the divergence is real.

James Hoffmann James Hoffmann
May 26, 2026 12 min read