We propose a simple fluid sensor: a low cost electronic device which can be used to control fluid levels and flows and to monitor several processes in dynamic systems. It can be integrated in power devices as electric pumps to implement or detect safety conditions, or in sensor networks as pervasive resource for monitor environmental changes or to detect contaminants water, air and soil. This sensor exploits several features as: - physical fluid detection and management in mobile environments, - electrochemical fluid discrimination, - flux estimation. The first prototype is based on a single Micro Controller Unit (MCU), a standard Microchip PIC implementing the necessary programmed logic, signal generation and processing. A power section switch is included on the board, where for critical environments the relay has also been substituted by a suitable MOSFET. The paper describes the hardware and software …