Biomimetic Rod-Magnet-Hall-Effect Sensing for Low Power Airflow Detection in Small Drones

Abstract

Small autonomous drones require lightweight, low-power sensing systems that can detect environmental forces without adding significant payload or computational demand. This study investigates a biomimetic rod–magnet–Hall-effect sensing system inspired by insect antennae and mechanosensory hairs. A computational model was developed to simulate how airflow or physical contact deflects a lightweight rotating rod with an attached permanent magnet. As the magnet moves relative to two Hall-effect sensors, the magnetic field and differential sensor voltage change, allowing rod angle and relative wind speed to be estimated through calibration and inverse modeling. The simulation tested relative airflow speeds from 0 to 20 m/s and included sensor noise, body tilt, and propagated wind-speed uncertainty. Results showed that the system produced a smooth and monotonic voltage response to rod deflection, and estimated wind speed closely followed the true wind speed under idealized model conditions. Uncertainty was highest at very low wind speeds, where rod deflection and voltage changes were small, but remained low across most of the tested operating range. These findings support the feasibility of the rod–magnet–Hall-effect concept as a lightweight biomimetic sensing approach for small drones. Future work should focus on physical prototype testing, wind-tunnel validation, drone-mounted trials, and multi-sensor configurations for directional airflow and contact detection.