Abstract: Concentrated lines of flux through two loosely mounted magnetically contacting reeds are intermittently mechanically interrupted by breaking the contact infinitesimally, thus deriving a near-maximum generated EMF in a coil surrounding the contact. A piezo transducer driven in feedback arrangement by an oscillator provides an energy-efficient drive for a hammer that irregularly strikes one of the reeds. A compass based on this noncoherent modulation of a flux path is shown and other devices based upon this principle are mentioned.