This app operates in a similar manner to other hand-held stud detector tools: as you move the device along the wall, the needle will move and a beep can be heard. The compass sensor detects subtle changes in the background magnetic fields caused by the conductive metal fasteners that are located in all wooden studs. Features: - Automatic sensor that measures the magnetic field in uT. - Active detection beep. - You can store the time when the stud is detected. I made a quick video tutorial that shows how the app works: https://www.youtube.com/embed/gTQHwS7XwXk?rel=0 Happy construction. Download now!