an electromechanical pulse generator and a method of generating electrical pulses are disclosed . the electromechanical pulse generator comprises very few parts and includes an effective mechanism to prevent contact rebound . an upper , user - actuable and rotatable part has a surface with a plurality of projections . a lower part has an electrical conductor with a displaceable resilient contact portion biased against the projections and two electrical contacts positioned , in the plane of rotation , on either side of the displaceable contact portion .