Abstract: A speed alarm system which is actuated by the pointer of a speedometer. The device is completely self-contained and self-powered. It is adapted for attachment to the existing speedometer of an automobile or the like with a minimum of modification. It includes a battery powered audible oscillator which, when the battery circuit is closed to the oscillator, drives a transducer which generates an audible warning sound loud enough to be heard by the driver. Closure of the circuit is effected by a special type of switch in the shape of a small cylinder which may be inserted from the outside through a hole drilled in the plastic cover plate of the speedometer at the point at which the speed warning is to be sounded. The switch includes a hair-fine wire extending axially of the cylinder beyond the end thereof so that it may be moved by the speedometer pointer to contact a metallic sleeve of the activation switch, thus completing the circuit to energize the transducer.