Cryonics Monitoring is building a "smart ring" that tracks hand movement

​Cryonics Monitoring is building a "smart ring" that tracks hand movement

Cryonics often sounds like a philosophy of the future. But in practice, it breaks on something painfully ordinary: a person dies alone, and nobody finds out in time. And here, "in time" is measured not in hours, but in that first hour, when warm ischemia makes the brain less and less suitable for any kind of "medical archaeology" in the future.

In February 2026, the Biostasis Technologies newsletter announced a talk titled "Advancing Reliability in Cryonics Monitoring," including a live demo of a "smart ring" from the engineering group Cryonics Monitoring. On its website, the group also lays out the specs for a custom ring being built specifically for "monitoring for cryonics."

Their bet for triggering an alert is not pulse, but movement. The logic comes from simple everyday statistics: "the wrist moves thousands of times a day and dozens of times at night," so a lack of movement is a fairly reliable sign that "something has gone wrong."

The ring continuously monitors the hand with an accelerometer and raises an alert when there is no "expected movement." In their description, they give a rough estimate: based on their data, such pauses average about 45 minutes during the day and 90 minutes at night.

We developed a smart ring from scratch specifically for cryonic monitoring. The system continuously measures hand movement and alerts when expected movement is absent.

The device is designed for bad-case scenarios: more than 48 hours on a single charge, wireless charging in 2 hours, connectivity via Bluetooth and long-range LoRa, plus Wi‑Fi on the charging station. There is an external low-battery indicator and an optical sensor that checks whether the ring is actually being worn on a finger.

The project history includes one important marker: in an update dated 4 November 2025, the team says the "core technology" has already been assembled, and that the prototype includes pulse measurement in addition to motion.

Why move away from "smartwatches with a pulse sensor" in the first place? In its Fitbit Sense review, Cryonics Monitoring explains why the optical pulse sensor is often a "black box": it behaves differently depending on conditions and can change after software updates.

The same review includes an illustration of that variability in the form of "raw chicken" tests: the alert sometimes triggers quickly, but in a test series (n=30), many values cluster around 3 hours 45 minutes.

The problem is that the pulse sensor is a "black box": the manufacturer can change the data processing, and we may not even know. That makes it nearly impossible to predict in advance how it will behave in a real-world scenario.

The weak point of this project is obvious too: the description includes no data on field testing, false alarms, or how the system behaves during long stretches of stillness for entirely ordinary reasons. For now, this is a proposal for a new class of infrastructure, not a medical device.

But the attempt itself matters: cryonics grows up at exactly the moment it stops arguing about hope and starts building boring mechanisms that buy time.

Summary

Cryonics Monitoring is developing a custom accelerometer ring specifically for cryonics: the device tracks hand movement and triggers an alert when movement is absent for too long (~45 minutes by day, ~90 at night), because with mass-market wearables, "pulse = black box," while lack of movement is a stable signal that does not depend on firmware. The ring is designed for bad-case scenarios: >48 hours of battery life, LoRa+Bluetooth+Wi‑Fi, and an optical wear-detection sensor. For now, it remains a prototype without public field data (false alarms, long stillness for benign reasons), but the underlying bet matters: cryonics is moving from a philosophy of "hope" to the construction of boring infrastructure that buys crucial minutes in the critical "first hour."