Economical hand-pushed digital cone penetrometer

The cone penetrometer is widely used in tillage and off-road mobility researches as an indicator of soil strength and density characteristics. Light-weight, manually operated units are especially useful in recording cone index determination at remote field locations. An electronic hand-pushed soil penetrometer with a microcontroller-based data logging system was designed and fabricated to provide a portable penetrometer for determining soil resistance to penetration in tillage studies. The device consists of three main components: a cantilever beam strain-gauge load cell held by housing to measure penetration force, depth measurement mechanism with a photodiode sensor, and a data logging system for amplifying, digitizing, and acquiring data. Data from the data logging system can be downloaded into a personal computer by an RS-232 cable and a software program. In evaluation stage, the performance of the developed penetrometer was compared with an Eijkelkamp hand-pushed digital penetrometer in controlled soil bin conditions. No significant difference was found (p <0.05) between the two penetrometers. The penetrometer performance was reliable and the mechanical and electrical parts worked without any mal- function. The device is very light, easy to use and more economical compared to the conventional types.