Characterizing Positional Sensitivity of Low-Cost Load Cells for IoT-Based Weighing Systems

Accurate weight measurement is essential for various IoT applications, especially when using low-cost single-point load cells. However, the accuracy is often affected by the load position on the platform. This study investigates the measurement accuracy and stability of a 5 kg single-point load cell with load placement variation. A 30 × 30 cm plywood was mounted over the sensor, with 25 representative load positions were selected. Experiments were conducted using 200 and 500 g weights, each repeated ten times per position. Results show that measurements near the sensor's load application point, the platform's center, had the highest accuracy up to ±99.90%, with RMSE below 1 g, while loads placed near the corners exceeded 2.37 g. Despite variation, the standard deviations remained consistently low, indicating stable sensor behavior. Therefore, a 20 × 20 cm platform is recommended for high accuracy. The results provide valuable insight into platform design and load cell placement, especially for cost-effective and reliable weighing systems in IoT environments.