US Patent 8046946 Shot-counting device for a firearm

A device for counting shots fired by a firearm including a permanent magnet mounted to moving portion of the firearm and electrically coupled to a coil mounted on a relatively stationary portion of the firearm. Movement of the magnet relative to the coil induces an electromotive force within the coil. The induced electromotive force can be used increment a shot-count indictor and thereby record the number of shots fired by the firearm. The electromotive force can also be measured by a verification circuit to determine the strength of a shot and thereby verify whether a round was actually discharged by the firearm. In some embodiments, information regarding the number of shots discharged and the strength of the shots can be transmitted to an external device.