G-Shock Smart Sync is an unofficial, open-source Android app for G-Shock, Edifice, and Pro Trek watches. It allows you to control your watch, sync data, and configure settings without a Casio ID.
It offers a faster, privacy-focused, and more powerful alternative to the official Casio app.
- No Account Required: Skip the Casio ID login entirely.
- Voice Control: Manage alarms, timers, settings, and reminders using natural language commands.
- Calendar Sync: Push your calendar events (Google, Samsung, etc.) to your watch as reminders.
- Auto Timezone: Automatically adjusts watch time when you travel.
- Remote Control: Use your watch buttons to take photos, control music, or launch voice assistants.
- Alarm & Timer Sync: Configure watch alarms and timers easily from your phone.
- Phone Finder: Trigger a loud alarm on your phone to find it.
- Health Integration: View step counts and fitness metrics for supported models.
The app works with many Bluetooth-enabled G-Shock, Edifice, and Pro Trek models.
| Series | Compatible Models (Examples) | Note |
|---|---|---|
| Square | GW-B5600, GMW-B5000, GW-B5000, DW-B5600, TRN-50 | Classic square design support |
| CasiOak | GA-B2100, GBM-2100, GMC-B2100, MRG-B2100 | Octagonal bezel models |
| G-Steel | GST-B100 to B1000, GST-W1000, ECB-900 | Metal series |
| Edifice | ECB-10 to ECB-2300, EQB-500 to EQB-2000 | Bluetooth Edifice series |
| MT-G / MR-G | MTG-B1000/B3000/B3100, MRG-B5000/B2100 | Premium metal and carbon models |
| Others | ABL-100WE, GBD-100/200, GBD-H1000/H2000, GPR-B1000 | Step trackers, GPS, and sensors |
Here is a guide to the main screens of the application.
This is the first screen you see. It handles the Bluetooth connection to your watch.
- Status: Shows generic connection status.
- Scan/Connect: Automatically scans for your watch.
- Paired Devices: Lists your previously connected watches for quick access.
The app communicates directly with the watch via BLE. Connection is typically much faster than the official app (~3.5s vs 12s).
Manage your watch's timekeeping and control features via voice.
- Voice Control: Tap the microphone icon on the watch name card to issue voice commands.
- Say "Help" for a full list of supported commands.
- Examples: "Set alarm at 7:30 am", "Set timer for 5 minutes", "Disable all alarms", "Reset settings".
- Local Time: Displays the current time from your phone.
- Send to Watch: Tap the button to sync your phone's time, timezone, and DST settings to the watch immediately.
- Battery & Temp: Displays the current battery level and temperature reported by the watch.
Read and configure the alarms stored on your watch.
- View Alarms: See the current settings for all 5 alarms and the hourly signal (Chime).
- Edit: Tap any alarm to change its time.
- Sync: You can send these alarm settings to the watch.
Note: Due to Android limitations, we cannot read alarms set in your phone's native Clock app, but we can set the watch's internal alarms.
Sync your Android calendars to your watch!
- Upcoming Events: Lists future events from your phone's calendars.
- Send to Watch: Pushes these events to the watch's Reminder feature.
- Manual Mode: Switch to manual mode to create reminders directly in the app that won't be overwritten by your phone calendar.
- Transliteration: Automatically converts Cyrillic and other unsupported characters to Latin for watch compatibility.
Turn your watch into a remote control. Assign actions to button presses on the watch.
- Available Actions:
- Find Phone: Make your phone ring loudly.
- Take Photo: Snap a picture with your phone's camera.
- Flashlight: Turn on your phone's flashlight.
- Media Control: Play/Pause and Next Track for music.
- Voice Assist: Launch Google Assistant.
- Set Prayer Alarms: Set the watch's 5 alarms to Islamic Prayer Times.
- How to use: Short-press the lower-right button on the watch (when in Time mode) to trigger the selected action.
Configure app and watch preferences.
- Watch Settings: Adjust light duration, power saving, date format, language, and more.
- App Settings: Configure theme, connection behavior, and notifications.
- Smart Defaults: Easily reset all settings to optimal defaults based on your phone's locale and watch model.
G-Shock Smart Sync is built with privacy in mind. We do not require an account, and we do not collect your personal data.
- No Account Required: Use all features without a Casio ID.
- Local Processing: All data stays on your device.
- Open Source: The code is transparent and auditable.
Read our full Privacy Policy for more details.
- F-Droid: Download here
- GitHub: Download APK from Releases
- Google PlayStore: Download here (Un-branded version)
We welcome contributions!
- Code: Submit a PR to add features or fix bugs.
- Watches: If you have a G-Shock model not yet supported, functionality can often be added. Donations of test units are also highly appreciated to help expand compatibility.
| Project | Description |
|---|---|
| GShockAPI | The core Android library that this app is built on. It encapsulates all low-level Bluetooth communication and watch protocol logic into a clean Kotlin API. |
| G-Shock Time Server | A Python script that acts as a headless time server for Raspberry Pi or other always-on Linux devices. |
| G-Shock API for ESP32 | Standalone G-Shock time server for ESP32 microcontrollers — no phone or PC required. |
| G-Shock Smart Sync Webapp | Experimental web-based app for watch synchronization from a browser via Web Bluetooth. |
| gshock_api | A Python API library for G-Shock watches, featuring a pure functional architecture. |
Wireshark can be used to inspect the raw Bluetooth Low Energy (BLE) packets exchanged between your Android phone and the G-Shock watch. This is useful for reverse-engineering watch protocols or debugging communication issues.
Android has a built-in BLE packet logger. Enable it via Developer Options:
- Go to Settings → About Phone and tap Build Number 7 times to enable Developer Options.
- Go to Settings → Developer Options.
- Enable Bluetooth HCI Snoop Log (exact label varies by device/Android version).
- Restart Bluetooth (toggle it off and on) to start logging.
- Reproduce the action you want to capture (e.g., connect the app to the watch and sync time).
- Disable the snoop log again, then pull the log file from the device:
adb bugreport bugreport.zipThe HCI log is embedded in the bugreport. Alternatively, on many devices it is available directly at /sdcard/btsnoop_hci.log.
# Ubuntu / Debian
sudo apt install wireshark
# macOS (Homebrew)
brew install --cask wiresharkOr download the installer from wireshark.org.
- Open Wireshark and go to File → Open, then select
btsnoop_hci.log. - Wireshark will decode the BLE packets automatically.
- Use display filters to focus on relevant traffic:
| Goal | Filter |
|---|---|
| All BLE ATT traffic | btatt |
| Specific device by address | bluetooth.addr == AA:BB:CC:DD:EE:FF |
| ATT write operations | btatt.opcode == 0x12 |
| ATT notifications | btatt.opcode == 0x1b |
- Right-click a packet → Follow → Bluetooth ATT Stream to trace a full conversation.
This project is licensed under the MIT License - see the LICENSE file for details.