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On the Design and Construction of Dual-Probe Heat-Pulse Soil Moisture Sensor: Towards an Industrial Solution

Authors:
Antonio Valente
Arata Saraiva
Nuno Ferreira
Salviano Soares

Keywords: soil moisture sensor; soil thermal properties; dual-probe; heat-pulse sensor; thermal conductivity; thermal sensors.

Abstract:
There is a need for a multi-functional probe for small-scale measurements of different soil properties measured within identical soil volumes. Dual Probe Heat Pulse (DPHP) sensors are an economical solution for this since they measure simultaneously temperature, volumetric water content, and soil thermal properties: diffusivity and volumetric heat capacity. However, all DPHP sensors to date have very complex manufacturing processes. This paper aims to design and build a DPHP sensor based only on PCB board, which comprises the probes and all supporting electronics leading to a low cost and simple manufacturing process. The proposed system includes signal-processing circuits, a microcontroller, and communicates by a Serial Digital Interface at 1200 baud protocol (SDI-12). Probe spacing calibration results showed a reasonably good agreement between measured and fitted data. In conclusion, results also show that it is possible to build the multi-functional DPHP sensor in a low cost process, and this was the first time that a multi-functional probe was build using a Printed Circuit Board (PCB) as support.

Pages: 43 to 48

Copyright: Copyright (c) IARIA, 2018

Publication date: March 25, 2018

Published in: conference

ISSN: 2519-836X

ISBN: 978-1-61208-621-7

Location: Rome, Italy

Dates: from March 25, 2018 to March 29, 2018