Low-cost Semi-automatic Design of Tactile IoT for Accessible Education

Blind and low-vision (BLV) students continue to encounter significant barriers when educational content depends on graphical structures that conventional assistive technologies cannot effectively convey. This paper presents a low-cost method to upgrade 3D-printed tactile graphs from passive artifacts to tactile IoT systems capable of sensing user interaction, thus enabling potential real-time audio feedback. Building on a previous LLM-guided semi-automatic workflow, we generate assembly-ready models with detachable nodes and dedicated sockets for functional components. We propose a passive radiofrequency node-identification mechanism in which a single copper loop, interrogated via impedance measurements, is inductively coupled to frequency-coded resonant solenoids embedded in the nodes. The simulative and experimental results show repeatable touch-induced impedance changes (resonance downshift and amplitude reduction), enabling reliable discrimination of the touched node.