Thước Thủy

The spirit level turns your phone into an accurate spirit level thanks to its accelerometer sensor: a circular bubble level (2D bubble level) when the phone is placed flat, and a 1D level when the phone is placed against an edge. It displays the tilt angle to within 0.1°, vibrates gently when level, and adjusts to a standard plane to eliminate errors. The screen remains illuminated during operation. It works completely offline and requires no permissions.