# OpenWatch: reconstructing the LJ736/LY736D smartwatch BLE client

> OpenWatch implements an Android companion for LJ736/LY736D-based smartwatches using BLE commands reconstructed from the LaxaFit Pro APK and captured traffic. It handles pairing, notifications and clock synchronization locally, and can buzz the watch to help locate it. Protocol notes describe packet framing and watch-face transfer; the author reports that custom watch faces still display as blank black screens.

- 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/mehranshahmiri/openwatch-LY736D>
- Primary source: <https://github.com/mehranshahmiri/openwatch-LY736D/blob/9a79b6ecac73ebb31739d3fb80e8a8e932e19f5a/README.md>
- Catalog page: <https://awesomerea.org/resources/openwatch-ly736d-case/>
- Record JSON: <https://awesomerea.org/resources/openwatch-ly736d-case/record.json>
- Chinese version: [简体中文](https://awesomerea.org/zh/resources/openwatch-ly736d-case/index.md)

## Requirements & limits

- **Prerequisites:** Android Studio, JDK 17 and Gradle 8; minimum Android SDK level 26.
- **Prerequisites:** Custom watch-face builds require the user's own LaxaFit Pro font asset.
- **Scope:** A compatible LJ736/LY736D watch; hardware testing covers one LJ736 board with a 240×296 display.
- **License:** MIT License.

## Primary sources

1. <https://github.com/mehranshahmiri/openwatch-LY736D/blob/9a79b6ecac73ebb31739d3fb80e8a8e932e19f5a/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.