Date and Time Synchronization
The MNemo v2 stores the date and time of each survey. It is important to ensure the device's clock is correctly set before going on a dive, as an incorrect date/time will affect the timestamps recorded in your survey files.
How to Synchronize the Date and Time
From the web interface (recommended)
The easiest way to set the clock is from the device's built-in web page over WiFi — no extra software beyond a browser once WiFi is available.
- Turn WiFi on (see Wireless Data Transfer) and open the Mnemo's page in your browser. (v3.1.0+: scan the QR code shown on the OLED.)
- Open the Settings page from the top menu.
- Under Time & Format → Date & time, tap Synchronize date & time.
The device clock is set to the current date and time of the browser (i.e. your phone or computer). Two taps and you're done.
Tip: Make it a habit to open the Mnemo page and tap the sync button at the start of every dive trip.
Over the USB serial console (advanced)
Power users can also sync the clock over USB by sending the syncdatetime command on the device's serial port (57600 baud) followed by 5 bytes (year minus 2000, month, day, hour, minute). This is the protocol that desktop helper tools use under the hood.
Checking the Current Date and Time
You can verify the current date and time directly on the device from the Main Menu. The bottom status line shows:
| Display | Description |
|---|---|
| 26/03 11:26 27.6ºC | Day/Month Hour:Minute Water Temperature |
The Day/Month order can be swapped to Month/Day on the web Settings page (Time & Format → Date format).
If the date and time look incorrect, follow the steps above to resynchronize.
Potential Issues When the Date Has Not Been Synchronized
If the device's clock has not been synchronized, the following issues can arise:
- Incorrect survey timestamps: each survey is recorded with a date and time. If the clock is wrong, it will be difficult to match a survey to the date of the actual dive.
- Default date fallback: if the internal clock has lost its settings (for example after a fully depleted battery), the device falls back to a default date. A DATE RESET warning is shown for a few seconds when the Mnemo is turned on to alert you.
- Data-management confusion: when reviewing surveys in your cave-survey software, incorrect dates make it harder to organise and identify dives, especially when multiple surveys are stored on the device.
Important: if you see the DATE RESET warning when turning on your MNemo, resynchronize the clock from the web interface before your next dive.