An automatic time domain reflectometry device to measure and store soil water contents for stand-alone field use

A field set-up was developed to measure soil moisture content on ten different positions using the time domain reflectometry (TDR) technique. The set-up works on a 12 V battery or solar panel system, independent of an external power source, has low power consumption, and compact dimensions. The system consists of a microprocessor-driven TDR instrument connected to a palm-top computer through a serial RS232 communications line. The system is controlled from the palm-top computer incorporated in the design. Measuring intervals between one minute and twenty-four hours can be chosen in one-minute steps.