This digital ferromagnetic detection system is a highly sensitive safety tester specifically designed for MRI rooms. It protects the tomography system around the clock from certain metal objects that are brought into the room by patients and may pose a risk to the MRI scanner. The detector’s design was inspired by a knight’s visor in order to visualise the concept of a guardian. The light signal has a high warning effect and its green, yellow or red light indicates whether there is any danger or not.