This project presents a novel compact system for measuring forces under the foot, designed for collecting data during rehabilitation of Achilles tendon ruptures. The system aims to provide valuable information to both patients and healthcare providers, enabling more personalized and effective treatment.

The core component of this system is a smart insole that can sense 3D forces (normal and shear forces), using a grid of 73 Hall effect sensors on a flexible printed circuit board shaped as the sole of the foot. The insole and supporting electronics are integrated into a standard orthosis, with two additional inertial measurement units for joint angle estimation.

Results demonstrate the feasibility of Hall effect sensors for measuring 3D force profiles under the foot, with a nearly linear response to vertical pressure. However, experiments also show hysteresis which can lead to measurement errors. Thus, future work will have to overcome this issue in order to achieve the accuracy required for clinical deployment.