An electrical resistivity tomography system for imaging at laboratory scale

Abstract

Over the past century, there has been an increase in the use of electrical resistivity tomography in environmental research for subsurface characterization. Although commercial devices emphasize robustness and measurement quality, their lack of flexibility and high cost make them unsuitable for budget-constrained applications like research and educational purposes. This paper presents a low-cost DC resistivity meter that provides an adaptable tool for small-scale research in both laboratory and field environments. The proposed device is built around an Arduino Due board integrated with a four-channel 16-bit analog-to-digital converter. In addition, two custom shields are incorporated for signal conditioning and multiplexing. The firmware system allows users to configure key parameters, including array sequences, the number of repetitions, reverse measurements, acquisition frequency, and delays between measurements. Repetitive and reverse measurements contribute significantly to the accurate characterization of measurement errors. Its compact, cost- effective, and fully customizable design makes it particularly innovative in overcoming the limitations of current commercial alternatives. Laboratory tests validated the efficacy and reliability of the proposed device. Comparative analysis with a commercial resistivity meter (Iris Syscal R1) further reinforced these findings, revealing an excellent agreement (R² = 0.999) between measurements acquired by the two instruments. These results highlight the system’s optimal performance and the remarkable consistency of its measurements.