Smart position detection of shelf-load based on imbalanced load cell sensors

Abstract

A strain gauge load cell is a transducer capable of converting pressure into a variation of electrical resistance. This variation in resistance is measured as a voltage change through an electronic circuit based principally on the Wheatstone bridge. Full bridge configuration requires precise calibration of the sensors to guarantee accurate measurements and reliable data. However, employing unbalanced load cell sensors can result in inaccurate measurements. This drawback can bring benefits to another valuable innovation. In this paper, a smart detector of position that operates as a weighting scale system is designed and tested. Four load cells were used to build the prototype sensing platform to reach this aim. The preliminary results show that each position on the balance pan has a specific ADC value for the 1kg reference weight, which is completely different from the values at the other pan’s positions. Therefore, unbalanced load cells result in varying weight values for the same object, depending on its position on the balance pan. The prototype showcased in this paper has the capability to operate as a real-time industrial system for tracking product sales. Efficient tracking of objects prevents stockouts and excess inventory.