Development and implementation of a low-cost data acquisition system using single-board computers to measure volumetric water content

Abstract

The work described in this thesis is aimed at exploring the use of single-board computers, specifically the Raspberry Pi platform, to measure volumetric water content of soils or other porous media. We first investigated the different methods to condition and measure signal frequencies. Subsequently, we designed and fabricated a Hardware Attached on Top frequency counter add-on board for the Raspberry Pi based on the reciprocal frequency counting method, and found that this accurately and precisely measures frequency signals from water content reflectometers. We then built a dormant deploy-and-forget sensor system around this hardware. The system will be used at our research field site in Brunei Darussalam to measure volumetric water content of peat. Further work focuses on improvements to the encapsulation of the electronic hardware, and designing a multiplexer-controlled relay board to acquire signals from multiple reflectometers simultaneously.