Abstract: Method and device for detecting interferences between surfaces of cooperating elements, including detecting the impact energy generated by an interference between a first surface and a surface protrusion of a second surface, and detecting a protrusion of interest based upon such impact energy. A preferred embodiment includes integration of an interference signal from a transducer associated with one of the surfaces. The integral is used to compare the seriousness of an interference against an interference energy threshold. Embodiments include a head/disk interference (HDI) detector.