For the car
What is the G-sensor in a dash cam?
The G-sensor is a motion sensor (an accelerometer) found in dash cams. It detects impacts, hard braking and strong jolts and, at that moment, locks the video being recorded so loop recording cannot erase it. That way the moment of a crash stays saved.
How it works with loop recording
A dash cam records in short segments, from one to five minutes. When the memory fills up, it deletes the oldest segments and keeps recording: that is loop recording, and it is why the camera never stops.
When the G-sensor detects an impact, it marks the current segment as protected (often moving it to an events folder) and the loop can no longer delete it.
Sensitivity matters
If it is set too high, every pothole or speed bump counts as an impact and the memory fills with protected videos that are not deleted automatically. If it is too low, a minor collision may not be saved. A medium setting is usual, adjusted to your roads.
In parking mode, the G-sensor wakes the camera if someone bumps the parked car. For that, the camera needs power while the car is off: a hardwire kit or a built-in battery.
What to check before you buy
- Make sure the G-sensor sensitivity is adjustable.
- Use a good quality microSD card and check the protected events folder from time to time.
- If you want monitoring while parked, confirm the camera has parking mode and how it is powered.
Frequently asked questions
Almost always because of videos locked by the G-sensor, which the loop does not delete. Lower the sensitivity and delete or download the events folder.