Web Interface

The buoy serves its own web pages over its WiFi network, and this is where you drive it from: start and stop measurements, read live GPS data, download logs and change settings. This page walks through every screen in the order you meet it.

Connect to the network FASTRRR-DRIFTER and open 192.168.1.1 — the Getting Started page covers connecting in detail.

The pages are live

The pages update themselves as the buoy changes, about once a second, without reloading — you never need to refresh. A small indicator shows the connection:

• ● Live — connected and up to date
• ● Live (polling) — updating a little more slowly, which is normal with more than two browser tabs open
• ○ Offline — the phone has lost the buoy’s WiFi; rejoin and the page picks up again

Two devices at a time

The buoy’s WiFi accepts at most two phones or laptops at once. A third cannot join until one of the others disconnects.

The header

The top of every screen carries the same identity line: the device ID, the firmware version, the unit’s MAC address and its IP address. When you report a problem, this line is what support needs — a screenshot of the home page answers most of the first round of questions.

Waiting for a GPS fix

No fix yet: the amber banner, no Start button, and zeroes in the data table. Wait a moment and the fix arrives, as it does on the water.

Straight after switching on, the buoy has no position yet. The banner is amber and there is no Start button — a measurement cannot begin without a fix.

Two things in the table tell you how the search is going:

• Satellites climbs from 0 as the receiver finds them
• HDOP starts at 100.0 and drops as the fix improves — lower is better

The first fix after a big change of location can take one to two minutes. Note that the local time here shows a fallback timezone until the fix arrives, because the buoy works its timezone out from its own position.

Ready to start

Fix acquired. The green Start button appears and the data table fills with live values — press it and this frame runs the whole sequence.

The banner turns purple and a green Start measurement button appears. The buoy also gives a two-tone beep at this moment, which is what you listen for when the phone is in your pocket.

The table now shows live data, updating about once a second:

Row	What it tells you
Date / Time (UTC)	The buoy’s own clock, in UTC
Local time	The same moment in the timezone worked out from the GPS position
GPS fix	OK in green once the receiver has a position
Speed	Live speed over ground — this is the buoy moving, not the current
Direction (FROM)	Live course, labelled to match your direction-mode setting
Lat / Lon	Position in decimal degrees
HDOP	GPS quality — below about 2 is a good working fix
Satellites	How many the fix is using

Under the table sits Last 4 valid measurements, a short history in local time so you can check the previous result without leaving the page. Each row has an arrow pointing the way the current flows, whatever the direction-mode setting.

Deploy countdown

The countdown gives you time to get the buoy into the water. Nothing is recorded yet.

Pressing Start does not begin recording immediately. The banner turns blue and counts down — this is your window to get the buoy over the side and let it settle. The countdown lasts 10 seconds, and is set in the configuration file on the SD card.

The button becomes a red Cancel countdown. Cancelling here records nothing at all and returns the buoy to the ready state, which is exactly what you want when you realise the spot is wrong.

Measuring

Recording. The banner counts the window down and the data table keeps updating.

The banner turns green and counts down the measurement window. The buoy is now recording a GPS sample about once a second, and the live table keeps updating while it does — a useful sanity check that the buoy is drifting rather than snagged.

The red Stop measurement button is there for emergencies.

Stopping early invalidates the result

A measurement stopped before the window closes is marked invalid. That is deliberate: a shortened drift is not a measurement of the current. Let the window run out whenever you can.

Measurement complete

Finished. The new result appears at the top of the history table, and the buoy is ready for another run.

The banner turns grey, the button becomes Start new measurement, and the new result appears at the top of the Last 4 valid measurements table — speed in m/min with knots alongside, and the direction.

The buoy is ready for the next measurement straight away. There is no need to switch it off and on between measurements — each one gets its own log file.

For the full result, including the deviation figures and the sample count, open the measurement’s file on the Log files page.

Log files

Every measurement gets its own CSV file, newest first. Scroll the list and open one with View.

The Log files link at the bottom of the home page lists every measurement the buoy holds, newest first, 50 to a page. The top line gives the number of measurements and the SD card space — used, total and free — which turns red when less than 10 % is free. Each entry gives you:

• The filename, LOG_yymmdd_hhmmss.csv, timed in UTC. Files written by firmware older than 1.6.0 are named LOG_yy-mm-dd_hhmmss.csv and still work
• The same moment shown in both UTC and local time, so you can find a measurement by when you remember taking it
• View — opens the file in the browser
• Download — saves it to your phone
• Delete — removes it from the card, after a confirmation

At the bottom, Delete all logs clears every measurement and every old system log in one go. It asks for the update PIN, keeps the configuration file and the current system log, and is refused while a measurement or a countdown is running.

Deleting cannot be undone

Download anything you want to keep before deleting it. A deleted file is gone from the card.

Filenames are always UTC

The timestamps inside the files and the filenames themselves are UTC whatever timezone the pages display. That keeps data from different deployments directly comparable.

Settings

The Settings page. Scroll down inside the frame for the system logs, the clock and the diagnostic tables.

The Settings link opens with a Device config table — a read-only summary of how the buoy is currently configured, including the firmware version with the slot it runs from, and the SD card space. If a firmware update was rolled back, a Rolled-back update row names the version that failed. Below the table, each setting has its own block with its own Save button.

Setting	What it does
Measure time	How long a measurement records for, 30–600 s
Direction mode	Whether the displayed direction is where the current flows to or where it comes from. Display only — the logged data is unaffected, so this cannot corrupt your measurements
Start mode	Whether a measurement waits for a button hold, or starts automatically once there is a fix
Timezone source	AUTO works the timezone and daylight saving out from the GPS position with no configuration. MANUAL applies the fixed offset below
Manual timezone	The offset used when the source is set to MANUAL — worth setting close to a timezone border, where a position-based lookup can pick the neighbouring zone

Settings are stored on the buoy and survive a restart.

Further down the same page, past the settings themselves:

• System logs — the firmware’s own log files, separate from the measurement data. Files named SYS_NORTC_* were written before the clock had been set, so they carry no real date. Support may ask you for the current one
• Set RTC time (UTC) — the buoy sets its clock from GPS, so you rarely need this. Enter UTC, not local time
• Set debug mode — extra detail in the system logs. Leave it off unless support asks
• Set Bluetooth (BLE) — switch the phone app link off entirely for deployments where the app is not used, saving power. The change applies after the next restart
• Firmware update — the installed version and a link to the update page; see Updating the Firmware
• Debug and E-paper link — diagnostic counters. They are there for support rather than for daily use; an offline e-paper status on a unit with no e-paper display is normal

Next steps

• User Guide — what the measurements mean, the data format and maintenance
• Troubleshooting