A Passive Elastic-Folding Mechanism for Stackable Airdrop Sensors

TL;DR

This paper presents a passive elastic-folding hinge mechanism for stackable air-dispersed sensors, enabling low-cost, scalable deployment without active control, suitable for wide-area environmental monitoring from UAVs.

Contribution

Introduction of a scalable, passive elastic-folding hinge mechanism for sensors that simplifies deployment and reduces power consumption compared to active systems.

Findings

Fold angles between 10 and 100 degrees with high repeatability.

Reliable data transmission during dispersion in field tests.

Trajectory simulations suggest sensing coverage exceeding 10 km.

Abstract

Air-dispersed sensor networks deployed from aerial robotic systems (e.g., UAVs) provide a low-cost approach to wide-area environmental monitoring. However, existing methods often rely on active actuators for mid-air shape or trajectory control, increasing both power consumption and system cost. Here, we introduce a passive elastic-folding hinge mechanism that transforms sensors from a flat, stackable form into a three-dimensional structure upon release. Hinges are fabricated by laminating commercial sheet materials with rigid printed circuit boards (PCBs) and programming fold angles through a single oven-heating step, enabling scalable production without specialized equipment. Our geometric model links laminate geometry, hinge mechanics, and resulting fold angle, providing a predictive design methodology for target configurations. Laboratory tests confirmed fold angles between 10 degrees and 100 degrees, with a standard deviation of 4 degrees and high repeatability. Field trials further demonstrated reliable data collection and LoRa transmission during dispersion, while the Horizontal Wind Model (HWM)-based trajectory simulations indicated strong potential for wide-area sensing exceeding 10 km.