Wireless instrumented sphere for three-dimensional force sensing

In this work, a spherical shape portable data acquisition system capable of sensing compression and impact forces along the three Cartesian axes is presented. The developed instrument was validated in several different experiments of fruit packing houses during the post harvest process in order to check the mechanical damages they suffer. It is a microcontroller embedded system that acquires data from four sensors (accelerometers, load cells, temperature and humidity). A flash memory is used for data storage and a radio frequency transceiver and a universal serial bus (USB) communication port are provided to allow interface with external computers for data-processing and visualization. The case studies indicated strong compression and impact forces suggesting a need for changes in the mechanical and manual selection, packing and transportation of fruits. The developed device was proven to be useful, working as expected and its modular design allows future modifications. The preliminary results obtained with the instrumented sphere point to the need to more concern on damages fruits and vegetables endure along the post harvest handling chain.