# Daybreak: rebuilding COLMI R09 BLE communication for an offline ring client

> Daybreak rebuilds COLMI R09 smart-ring communication in an offline Android client. Its Kotlin protocol module handles 16-byte commands and checksum validation, reassembles multi-packet sleep records, and processes heart-rate logs, steps and SpO2 data; the app computes local sleep, recovery and activity scores from the readings.

- Type: Case study
- Targets: Protocol
- Category: Independent reconstruction cases
- Relationship: Independent reconstruction project
- Sources reviewed: 2026-11-06
- Added to the catalog: 2026-11-08
- Original resource: <https://github.com/reuhenbhalod/DayBreak>
- Primary source: <https://github.com/reuhenbhalod/DayBreak/blob/21dd3e3d5b1c2d5a0b23ecd2cd69f61f2334ba2e/README.md>
- Catalog page: <https://awesomerea.org/resources/daybreak-colmi-r09-case/>
- Record JSON: <https://awesomerea.org/resources/daybreak-colmi-r09-case/record.json>
- Chinese version: [简体中文](https://awesomerea.org/zh/resources/daybreak-colmi-r09-case/index.md)

## Requirements & limits

- **Prerequisites:** COLMI R09 smart ring and Android 8.0+ for the app.
- **Prerequisites:** JDK 17+ and Android SDK to build.
- **Limits:** The source notes firmware-dependent HRV and noisy sleep staging.
- **License:** MIT license.

## Primary sources

1. <https://github.com/reuhenbhalod/DayBreak/blob/21dd3e3d5b1c2d5a0b23ecd2cd69f61f2334ba2e/README.md>

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## About this entry

The description was reviewed against primary sources.
Original editorial content: MIT. Linked projects, papers and assets retain their own rights and licenses.