G-Meter

1.Overview

The G-meter extracts vehicle G from the device's built-in 3-axis accelerometer and renders a ball with a trail on a circular grid. The center is zero G; the further out the ball moves, the higher the force.

Accurate readings require a calibration step that compensates for the device's mounting angle. Calibration runs on a long-press while stopped, or automatically when a recording starts.

When you play back or export a recording in the Desktop app, a "zero correction" automatically cancels out small residual mounting errors (see §6).

From v1.3.7 you can record G that shows up in record details even without a G-meter on the dashboard (see §3).

2.On-screen elements

The display contains the following elements:

Axis mapping

3.Calibration

Because the G-meter depends on the device's mounting angle (dashboard tilt, mount orientation), calibration before use is mandatory. Two methods are available: manual and automatic.

Manual calibration (long-press)

1. Long-press the G-meter widget while stopped
2. The app averages the next 10 samples (about 0.2 s) to estimate the gravity vector
3. A rotation matrix is computed so that gravity points straight down
4. The matrix is saved on-device (persists across app launches)

The long-press only triggers when vehicle speed is 0 km/h (from ECU or GPS). It will not run while moving. Only pitch and roll are corrected — yaw (heading) is not. Portrait and landscape both work (orientation is detected automatically), but the top edge or side of the device must point straight ahead. A skewed mount mixes lateral and longitudinal G.

Auto-calibration on recording start

If a G-meter is placed on the dashboard, the same calibration runs automatically the moment a recording starts, so you don't need to remember to long-press. It only runs at 0 km/h — if you start recording while already moving, it is skipped and the previous calibration is kept. A snackbar at the bottom of the screen reports the result.

Recording G without a G-meter (v1.3.7+)

You can show the G-meter in record details even for drives recorded without a G-meter on the dashboard — handy when you want the screen space for other gauges, or when recording with a layout such as Twin Meter.

1. Turn on Settings › Dashboard Settings › "Record G (without G meter)" (off by default)
2. When recording starts, a button with the G-meter icon appears at the top right of the header, next to ECO. It is orange until calibrated, and a "G is not calibrated" hint is shown when recording starts
3. Stop on level ground and tap the button. When calibration is done the icon turns green with a check mark

The button only works at 0 km/h (it is greyed out while moving). If you started recording on the move, tap it at your first stop. You can tap it again as many times as you like during the same recording.

Record details show G from the point you calibrated onward. The section before calibration is hidden because the mounting angle was not yet corrected. Re-calibrating does not move that starting point — it stays at the first calibration.

If a G-meter is on the dashboard, nothing changes regardless of this setting: auto-calibration when you start recording while stopped, and long-press to calibrate manually.

For drives recorded with v1.3.8 or later, the mobile record detail screen shows the G-meter only if G was calibrated during the recording (auto-calibration, long-press, or the button above). G from uncalibrated recordings is used only by Estimated Power calibration (to detect hills). Earlier drives still show G as before whenever G data exists (for drives calibrated in v1.3.7, from the calibration point onward). The Desktop app shows G in playback and export as before, re-centered by zero correction (§6).

4.Why it does not work on motorcycles

As noted in the slot setting screen, the G-meter does not function correctly on motorcycles. This is because the calibration logic assumes the device and vehicle stay in fixed alignment.

Motorcycles lean into corners, so lateral G is measured along an axis tilted relative to the road, not relative to the bike. As a result, gravity bleeds into the lateral G channel during cornering, and the pure centripetal force can't be isolated.

On four-wheel vehicles roll angles are small enough to ignore in practice, but on two wheels the error dominates.

5.Detail settings

The only configurable item under the Detail Settings tab is the meter range (maxValue), which defaults to 1.5 G. This is the maximum G represented by the outer ring — raise it if values clip during sport driving, or lower it for daily driving where the ball would otherwise sit close to the center.

The warning threshold (ball color shifts above 0.3 G) and the smoothing factor are fixed as internal constants and are not currently user-configurable.

6.Zero correction in the Desktop app

Calibration uses the direction of gravity at that moment as its reference. If the road surface was tilted where you calibrated, or the holder shifted slightly afterwards, the difference is recorded as a constant offset. In practice about 3° of tilt error shows up as roughly 0.05 G — the ball sits slightly off-center all the time. Roads are cambered toward the shoulder, so on left-hand-traffic roads the ball tends to sit slightly left.

From Desktop v1.0.18, playback and video export automatically subtract the median G of the whole recording as the zero point, re-centering the meter. This applies to recordings you already have. The whole recording is used rather than stopped samples because each stop varies by about ±0.05 G depending on the local road camber and grade.

You can toggle this under Settings › Dashboard › "G meter zero correction" (on by default). For recordings where the median itself is biased — laps on a circuit with corners mostly in one direction, or a one-way descent — switch it off to see the raw G.

7.Tips

• Always calibrate on first use (mount the phone first, then long-press)
• Re-calibrate after changing the mount angle or moving the holder
• Stopped-only: both the long-press and the auto-calibration on recording start only work at 0 km/h
• To keep G without a G-meter on the dashboard, turn on "Record G (without G meter)" in Settings and calibrate with the header button while stopped
• Calibrate on level ground where possible — a tilted surface leaves its tilt behind as an offset
• The combined G value (bottom-right) is the live reading, not a session maximum
• Not recommended for motorcycles

8.FAQ