Steps to build a DIY low-cost fixed-wing drone for biodiversity conservation

RESEARCH ARTICLE Steps to build a DIY low-cost fixed-wing drone for biodiversity conservation Geison P. MesquitaID1,2, Jose´ Domingo Rodrı´guez-Teijeiro3, Rodrigo Rocha de Oliveira4, Margarita Mulero-Pa´ zma´ ny5* 1 Department of Animal Biology, Plant Biology and Ecology, Autonomous University of Barcelona, Barcelona, Spain, 2 Institute Baguac¸u of Biodiversity Research, São Luı´s, Brazil, 3 Department of Evolutionary Biology, Ecology and Environmental Sciences, University of Barcelona, Barcelona, Spain, 4 Department of Chemical Engineering and Analytical Chemistry, University of Barcelona, Barcelona, Spain, 5 School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool, United Kingdom * m.c.muleropazmany@ljmu.ac.uk Abstract Despite the proved usefulness of drones in biodiversity studies, acquisition costs and diffi- culties in operating, maintaining and repairing these systems constrain their integration in conservation projects, particularly for low-income countries. Here we present the steps nec- essary to build a low-cost fixed-wing drone for environmental applications in large areas, along with instructions to increase the reliability of the system and testing its performance. Inspired by DIY (Do It Yourself) and open source models, this work prioritizes simplicity and accounts for cost-benefit for the researcher. The DIY fixed-wing drone developed has elec- tric propulsion, can perform pre-programmed flight, can carry up to 500 g payload capacity

with 65 minutes flight duration and flies at a maximum distance of 20 km. It is equipped with a RGB (Red, Green and Blue) sensor capable of obtaining 2.8 cm per pixel Ground Sample Distance (GSD) resolution at a constant altitude of 100 m above ground level (AGL). The total cost was $995 which is substantially less than the average value of similar commercial drones used in biodiversity studies. We performed 12 flight tests in auto mode using the developed model in protected areas in Brazil, obtaining RGB images that allowed us to iden- tify deforestation spots smaller than 5 m2 and medium-sized animals. Building DIY drones requires some technical knowledge and demands more time than buying a commercial ready-to-fly system, but as proved here, it can be less expensive, which is often crucial in conservation projects. Introduction In the last decade, drones (known as Unoccupied Aircraft Systems–UAS, or Remotely Piloted Aircraft Systems–RPAS) have been adopted as a new tool for the monitoring and conservation of protected areas [1]. These systems are used for identifying deforestation and fragmentation processes [2, 3], searching for illegal hunters [4] and conducting forest inventory and biodiver- sity assessments [5, 6] as well as wildlife surveys [7, 8]. The success of drones for biodiversity monitoring is primarily due to the high spatial and temporal resolution of the data obtained as PLOS ONE PLOS ONE | https://doi.org/10.1371/journal.pone.0255559 August 13, 2021 1 / 17 a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 OPEN ACCESS

Citation: Mesquita GP, Rodrı´guez-Teijeiro JD, de Oliveira RR, Mulero-Pa´zma´ny M (2021) Steps to build a DIY low-cost fixed-wing drone for biodiversity conservation. PLoS ONE 16(8): e0255559. https://doi.org/10.1371/journal. pone.0255559 Editor: Jana Mu¨llerova´, Institute of Botany of the Czech Academy of Sciences, CZECH REPUBLIC Received: July 3, 2020 Accepted: July 20, 2021 Published: August 13, 2021 Copyright: © 2021 Mesquita et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: All relevant data are within the paper and its Supporting information files. Funding: Funding for this research was provided to GPM by pre-doctoral scholarship from the Foundation for the Support of Research and Scientific and Technological Development of Maranhão (FAPEMA; BD-02130/15). There was no additional external funding received for this study. The founder had no role in study design, data