ADVANCED INSTRUMENTED SPHERE (IS) FOR IMPACT MEASUREMENTS
ABSTRACT The transportation and handling of agricultural products can result in various degrees of damage due to impacts. An 89-mm diameter self-contained, instrumented sphere (IS) was developed to record impacts it experiences while handled with like-sized commodities (apples, pears, peaches, oranges). This unit is approximately 1/4 the diameter of an earlier reported system, and has 32K of memory, EEPROM, smaller batteries, and simplified conditioning circuitry. The populated circuit board is foam insulated and then cast in beeswax for structural hardness. Analysis of recorded accelerations above a preprogranmied threshold allows estimates of fruit bruising that results from various impacts. Extensive laboratory drop tests were done using fruit and the IS to evaluate the reliability of predicted damage based on various impact characteristics (peak acceleration, velocity change).