A motion detecting system is attachable to an object for enabling and disabling an alarm flow of electrical current from a power source for actuating an alarm device. The system has a back plate with a substantially flat surface and a magnet freely pivotally mounted thereupon for generating a pivoting magnetic field that pivots with magnet in response to a motion of the object or of the system itself. System is set in an armed state by an electric pulse which causes at least one electrical contact is engaged by magnetic field in a first state to be set as an armed contact. When motion occurs, magnetic field pivots with magnet and armed contact in first state enters second state in which alarm flow is enabled for actuating alarm device. Contacts are spaced such that at least one contact is always engageable in first state.