A PRESSURE MEASURING SPHERE FOR MONITORING HANDLING OF FRUIT AND VEGETABLES

An ''artificial fruit'' was developed to detect damage sources for per ishable fruit and vegetables during practical harvesting and handling. This Pressure Measuring Sphere (PMS) is designed robustly in order to tolerate usual mechanical loads under practical conditions. It consis ts of a liquid-filled rubber ball with a pressure data acquisition sys tem embedded inside. The system contains a stand-alone microcomputer, a fluid pressure sensing unit and a battery. The PMS is capable to col lect all load events touching its skin, if they exceed a preset thresh old, and to store them together with time from an internal clock. Cali bration tests confirmed that the PMS senses static as well as dynamic mechanical loads. Measured load data were nearly reproducible under st atic load conditions (variation coefficient about 4%). Under dynamic l oad conditions a minimum of 15 measuring runs provide for representati ve results (variation coefficient about 20%).