Abstract: An electronically-controlled hammering module is used to apply a repetitive hammering force under electronic control to the top end of a dynamic cone penetrometer rod. In a preferred embodiment, the hammering module has a battery-powered percussive hammer that applies an electrically-generated impulse hammering force to the top of the rod. The depth of penetration is measured with a range-finder and used to compute the rate of penetration of the rod into the ground and correlated to the strength of the soil. The rate of hammering is controlled to cause the rod to penetrate into the soil at a controlled rate correlated with the strength of the soil.