Guide - Colmi ring
Colmi ring in FitMesh: everything we read today, plus the R09's temperature sensor
With the Colmi R-series (R02-R10) and OEM clones sharing the same BLE protocol, FitMesh Sync already reads steps, distance, calories, heart rate, resting HR, SpO2, HRV, stress, sleep with stages and battery over direct Bluetooth, merged with your smartwatch data with no double counting. The R09 model adds a skin-temperature sensor the R02/R03 don't have: here's everything the ring already does today, and how we use that sensor for one more wellness signal β verified on physical hardware, included in the app's current version.

TL;DR
- Today, with the Colmi R-series (R02-R10) and OEM clones sharing the same BLE protocol, FitMesh Sync reads steps, distance, calories, heart rate (with resting HR), SpO2, HRV, stress and sleep with stages over direct Bluetooth, plus the ring's battery level.
- Ring data merges with your smartwatch data in the same dashboard: the ring wins overnight for sleep, never double-counted when you wear both.
- Workouts aren't read from the ring: for those, you currently need a smartwatch or another connected source.
- The R09 has a real skin-temperature sensor, unique in the Colmi lineup: support is verified on a physical ring and included in the app's current version.
- Temperature is a non-diagnostic wellness signal β not a clinical tool.
If you wear a Colmi ring, FitMesh Sync already reads a lot of what it measures, no manufacturer companion app required. This page covers two separate things: first, what actually works today if you wear a Colmi R-series ring (R02-R10) or an OEM clone sharing the same BLE protocol. Second, what the R09 model does in addition, thanks to a temperature sensor the others don't have β a feature now verified on physical hardware and available in the app.
What FitMesh already reads from your Colmi ring today
FitMesh Sync connects to the ring over direct Bluetooth, no companion app in between. With a Colmi R-series ring (R02-R10) or an OEM clone sharing the same BLE protocol, you get steps, distance, calories, heart rate with a daily log plus resting HR, SpO2, HRV (RMSSD), a stress index, and full sleep with stages (light, deep, REM, awake). Ring battery is always visible in the app. One data point the ring doesn't cover: workouts. Recording workout sessions currently requires a smartwatch or another connected source.
| Metric | Available today | Notes |
|---|---|---|
| Steps | Yes | Daily log |
| Distance | Yes | Calculated from steps |
| Calories | Yes | Activity estimate |
| Heart rate | Yes | Daily log + resting HR |
| SpO2 | Yes | Spot and overnight readings |
| HRV | Yes | RMSSD index |
| Stress | Yes | 0-100 index |
| Sleep with stages | Yes | The ring wins overnight in multi-device fusion |
| Battery | Yes | Always visible in app |
| Workouts | No | Requires a smartwatch or another connected source |
| Skin temperature (R09 only) | Yes | Verified on physical hardware |
How ring data merges with your smartwatch data
If you also wear a smartwatch, FitMesh Sync doesn't add the two sources together: it applies a source-priority fusion, where the ring is the sleep specialist and wins overnight, while the smartwatch wins during the day for the metrics where it's more accurate. Each metric is counted only once, with the best source available at that moment β no doubled steps, no doubled hours of sleep.
The R09: same protocol, one extra sensor
The Colmi R09 is part of the same R-series (R02-R10) FitMesh supports today β same BLE protocol, same base metrics. The difference is hardware: the R09 (and the related Yawell R05) additionally includes an actual temperature sensor, which the rest of the series doesn't have. Today, that sensor is read by FitMesh too, verified on a physical, worn ring.
Temperature as a wellness signal
The command the R09 uses to expose temperature had never been documented in FitMesh before: we found it by analyzing the ring's BLE protocol, reverse-engineering work informed in part by public research from the open-source Gadgetbridge project on rings with similar hardware. The code to read and interpret that data β in the ring's protocol parser and in the pipeline that merges it with other sources β is written, verified on a physical, worn R09 ring, and our automated tests pass. The recovery index gains a factor tied to temperature deviation from your personal baseline, and the heart health card shows a note when temperature is above your norm.
Why temperature will never be a diagnosis
Just like the ring's SpO2 data today β treated as an informational estimate around possible overnight patterns, not a diagnosis β skin-temperature data is a non-diagnostic wellness signal, not a diagnostic tool. Smart rings, including the R09, are not medical devices and are not certified to diagnose illness or health conditions. A temperature deviation from your personal baseline is one more data point to watch over time, not a clinical verdict. For any real symptoms, an actual doctor's evaluation is what matters.
How we verified R09 temperature
Before including it in a public release, we verified the sensor works on a physical, worn R09 ring β checking that the temperature reading actually populates in the right card and that the recovery index uses it correctly. That verification is done: it's already in the version of FitMesh Sync available today. For details on what's new in the app, check the What's New section.
Frequently asked questions
Which Colmi ring models work with FitMesh?+
The Colmi R-series (R02-R10) and OEM clones sharing the same BLE protocol. Steps, distance, calories, heart rate, SpO2, HRV, stress and sleep with stages work across these models.
Does FitMesh already read R09 temperature?+
Yes. Support has been verified on a physical, worn R09 ring, and is included in the current build of FitMesh Sync.
Will ring temperature be able to tell me if I'm getting sick?+
No. Temperature is a non-diagnostic wellness signal, not a diagnostic tool. Smart rings are not medical devices. For any real symptoms, see a doctor.
Does the ring record my workouts?+
Not yet. Steps, distance and calories, yes β but workout session detection currently requires a smartwatch or another connected source.
If I also wear a smartwatch, does data get duplicated?+
No. FitMesh Sync merges sources by priority: the ring wins overnight for sleep, the smartwatch wins during the day where it's more accurate. Each metric is counted only once.
How did you verify R09 temperature actually works?+
We tested the reading on a physical, worn R09 ring, checking that the temperature data arrived correctly in the health card and that the recovery index used it as intended, before including it in the public build.
Disclaimer
FitMesh Sync is an independent product. Colmi is a trademark of their respective owners. This article implies no affiliation or sponsorship.
Medical disclaimer
The information in this article is for informational purposes only and does not replace advice from your physician, pharmacist or healthcare professional. FitMesh Sync is a fitness/wellness app, not a medical device, and does not diagnose or treat any conditions. For symptoms, clinical questions or treatment decisions always consult your primary care physician.
Written by
Matteo Pizzi
Founder & Solo Dev, FitMesh Sync Β· Fosforonero
Italian software developer. I built FitMesh Sync to fill the gap between my smartwatch and a real personal dashboard. Privacy-first, indie, EU servers.
More about the projectKeep reading
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