A sensor (11) for the automatic triggering of safety devices in motor vehicles comprises, inside the housing, a seismic mass (15) which has a permanent magnet (17) in a projection (16) at one end. The permanent magnet (17) is in operative connection with a Hall switch (22). The magnetic flux of the permanent magnet (17) is in such a form that the magnetic field passes through the Hall switch (22) with the sensor in the inoperative position. When the seismic mass (15) is tipped, both the direction and strength of the magnetic field change. This provides a clear measurement signal which can be evaluated by simple and economical Hall switches (22). The sensor (11) is suitable for extremely simple mass production.
