Citation: Oliveira, T.E.; Reis, J.R.;
Caldeirinha, R.F.S. Implementation of
a WSN for Environmental
Monitoring: From the Base Station to
the Small Sensor Node. Sensors 2022,
22, 7976. https://doi.org/10.3390/
s22207976
Academic Editor: Ángela María
Coves Soler
Received: 20 September 2022
Accepted: 14 October 2022
Published: 19 October 2022
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Article
Implementation of a WSN for Environmental Monitoring: From
the Base Station to the Small Sensor Node
Tiago Emanuel Oliveira
1,2
, João Ricardo Reis
1,2,
* and Rafael Ferreira Silva Caldeirinha
1,2
1
Polytechnic of Leiria, 2411-901 Leiria, Portugal
2
Instituto de Telecomunicações, 2411-901 Leiria, Portugal
* Correspondence: joao.reis@ipleiria.pt
Abstract:
In this paper, the implementation of a Wireless Sensor Network (WSN) for environmental
monitoring (EM) is presented. It includes the design, implementation and experimental charac-
terization of a multi-sector base station (BS) antenna composed of several microstrip Quasi-Yagi
elements and the implementation and experimental characterization of a reduced form factor antenna
for the sensor nodes (SN). Subsequently, it reports the implementation of a WSN based on Lopy4
transceivers, using the developed BS and SN antennas. Finally, experimental results obtained on
the field to evaluate the performance of the network in terms of maximum coverage distance and
coverage area are presented. According to the field tests, the connectivity between the sensor nodes
and the developed WSN base station is confirmed at distances above 3.5 km and for all the antenna
sectors of the multi-sector BS attaining a 360
◦
of field of view.
Keywords:
antenna; base station; differential; environmental; microstrip; monitoring; sensor node; WSN
1. Introduction
Wireless Sensor Networks (WSN) are often presented in the literature as a solution for
large-scale autonomous monitoring systems [
1
,
2
]. They are typically composed of multiple
sensor nodes (SN) scattered in a area of interest and a base station (BS). While the SN collect
physical parameters of the nearby environment, the BS collects, compiles and analyzes the
data from all nodes. In fact, these networks have appeared from the need of cooperative
monitoring solutions, particularly aiming at the environment [
3
–
5
], security [
6
,
7
], health
and quality of life [
8
–
11
] and agricultural [
12
,
13
] applications, among many others, or for
hazard detection [14–16].
In particular, the authors in [
3
] employ a WSN in a conservation of illegal logging
of the forest trees system. The foundation of this WSN is vibration sensors that are able
to detect variation in the vibration frequency caused by the illegal logging. The sensors
are coupled to a prototype developed based on a Zigbee platform. Whereas for the work
in [8]
, the authors proposed a project idea for an innovative public transport system which
ultimately depends on a distributed WSN for monitoring vehicle locations, traffic and
environmental conditions as well as public transit supply in real time. The authors choose
the multi-parameter ETL3000 station as an environmental monitoring system that measures
various pollutants (i.e., CO and O
3
)and weather parameters (i.e., humidity, temperature and
barometric pressure). Another example present in the literature is the work [
9
], where the
authors present a WSN to be integrated in smart cities for waste management optimization.
The authors developed a sensor node based on low energy consumption and cost, which is
able to measure a trash bin filling level by ultrasounds. Finally, in [
14
], the authors propose
Wireless Underground Sensor Networks (WUSN), to be deployed in tunnels, chambers or
earth air tunnels integrated in a smart cooling system. The WUSN monitor the ambient
temperature around the node; with this information, the system can then act to temperature
fluctuations preventing the underground area from becoming a hazard.
Sensors 2022, 22, 7976. https://doi.org/10.3390/s22207976 https://www.mdpi.com/journal/sensors
