A magnetic on-off robotic attachment device (MOORAD) (100, 300, 400, 624, 624′, 660, 676, 804) is used to make a number of systems, such as a mobile apparatus (608, 644, 668, 700, 700′), a belt mechanism (800) and a sensor device (504, 508, 656). The MOORAD allows the respective
system to be removably magnetically attached to a ferromagnetic structure / object (228, 420, 604, 604′, 720A-B, 720A′-B′, 848). Each MOORAD generally includes a
dipole magnet (104, 304A-B, 404) movable relative to first and second ferromagnetic portions (112, 116, 316A-D, 408, 412) that are separated by corresponding magnetically insulating portions (120, 320A-C, 416) so as to change that MOORAD between off and on states.