Botero-Valencia J S, Mejia-Herrera M, Pearce Joshua M
Grupo de Sistemas de Control y Robótica, Instituto Tecnológico Metropolitano, Medellín, Colombia.
Department of Electrical & Computer Engineering, Ivey Business School, Western University, London, ON, Canada.
HardwareX. 2022 Jan 29;11:e00267. doi: 10.1016/j.ohx.2022.e00267. eCollection 2022 Apr.
The measurement of outdoor environmental and climatic variables is needed for many applications such as precision agriculture, environmental pollution monitoring, and the study of ecosystems. Some sensors deployed for these purposes such as temperature, relative humidity, atmospheric pressure, and carbon dioxide sensors require protection from climate factors to avoid bias. Radiation shields hold and protect sensors to avoid this bias, but commercial systems are limited, often expensive, and difficult to implement in low-cost contexts or large deployments for collaborative sensing. To overcome these challenges, this work presents an open source, easily adapted and customized design of a radiation shield. The device can be fabricated with inexpensive off-the-shelf parts and 3-D printed components and can be adapted to protect and isolate different types of sensors. Two material approaches are tested here: polylactic acid (PLA), the most common 3-D printing filament, and acrylonitrile styrene acrylate (ASA), which is known to offer better resistance against UV radiation, greater hardness, and generally higher resistance to degradation. To validate the designs, the two prototypes were installed on a custom outdoor meteorological system and temperature and humidity measurements were made in several locations for one month and compared against a proprietary system and a system with no shield. The 3-D printed materials were also both tested multiple times for one month for UV stability of their mechanical properties, their optical transmission and deformation under outdoor high-heat conditions. The results showed that ASA is the preferred material for this design and that the open source radiation shield could match the performance of proprietary systems. The open source system can be constructed for about nine US dollars, which enables mass development of flexible weather stations for monitoring needed in smart agriculture.
许多应用都需要测量室外环境和气候变量，如精准农业、环境污染监测以及生态系统研究。为这些目的而部署的一些传感器，如温度、相对湿度、大气压力和二氧化碳传感器，需要免受气候因素影响以避免偏差。辐射防护罩用于固定和保护传感器以避免这种偏差，但商业系统有限，通常价格昂贵，并且在低成本环境或用于协作传感的大规模部署中难以实施。为了克服这些挑战，这项工作提出了一种开源的、易于适配和定制的辐射防护罩设计。该设备可以用廉价的现成部件和3D打印组件制造，并且可以进行适配以保护和隔离不同类型的传感器。这里测试了两种材料方法：聚乳酸（PLA），最常见的3D打印细丝，以及丙烯腈苯乙烯丙烯酸酯（ASA），已知它具有更好的抗紫外线辐射能力、更高的硬度以及总体上更高的抗降解能力。为了验证设计，将两个原型安装在一个定制的室外气象系统上，并在几个地点进行了一个月的温度和湿度测量，并与一个专有系统和一个没有防护罩的系统进行了比较。还对这两种3D打印材料在户外高温条件下的机械性能、光传输和变形的紫外线稳定性进行了为期一个月的多次测试。结果表明，ASA是这种设计的首选材料，并且开源辐射防护罩可以与专有系统的性能相匹配。开源系统的构建成本约为9美元，这使得能够大规模开发用于智能农业监测所需的灵活气象站。
