<![CDATA[Conventional geo-electrical resistivity meters require long and heavy cables to connect current and potential electrodes, making field deployment inefficient due to extensive cabling requirements. This work aims to develop and validate a Wireless Geo-Electrical Resistivity Meter (W-GERM) that reduces cable dependency by integrating a LoRa-based wireless sensor network for potential difference measurements while maintaining a wired current injection unit. The system consists of a main unit equipped with a 400 V current injector and multiple wireless multinode based on TTGO LoRa ESP32 and INA219 sensors. Performance evaluation included laboratory testing, communication and synchronization experiments, Contact Resistance Measurement (CRM) validation, and field testing using the dipole-dipole configuration at the Cikeruh River, East Bandung Basin. The proposed system provided reliable wireless communication and synchronized current injection with potential difference measurements. The calibrated INA219 sensors achieved potential measurement errors below 1%, while the CRM function reliably distinguished properly connected and improperly connected electrodes. Field validation produced subsurface resistivity profiles comparable to those obtained using the commercial AGIS Supersting R8, with a maximum survey length of 192 m and an investigation depth of approximately 20 m. The W-GERM reduces cabling complexity and provides a practical alternative for geo-electrical resistivity surveys.]]>
