Design and construction of an automated and programmable resistivity meter for shallow subsurface investigation

Abstract. Geoelectrical resistivity is an excellent method to investigate the structural composition of shallow subsurfaces. However, existing commercial equipment is typically expensive and often requires proprietary accessories and software to provide full system functionality. The objective of this study was to develop a multichannel, modular, automated, and programmable geo-resistivity meter capable of user customization and programming. To this end, a conceptual prototype was built based on free software and open hardware technologies as a low-cost alternative to commercial equipment while maintaining the accuracy and quality of the data at the same level. The prototype was based on electrode multiplexing to make the switching process more efficient by reducing cabling complexity, whereas synchronous demodulation for signal detection was employed, providing strong rejection of spurious electrical noise, typical of urban areas where such equipment is frequently used. The results demonstrate the feasibility of this project and an important academic contribution to open-source instrumental research.