A low-cost microprocessor and infrared sensor system for automating water infiltration measurements

Understanding the nature of soil infiltration properties is important for a number of applications, including planning efficient irrigation and erosion control practices, evaluating effectiveness of linings for sanitary landfills and waste lagoons, and landscape design and management. A common method for measuring infiltration is with the use of cylinder infiltrometers. This method can be very labor intensive and time-consuming, thus limiting its practicality. We describe the construction of an inexpensive system that can be readily adapted to single- and dual-ring infiltrometers to provide automated measurements on the scale of seconds to days. The system is comprised of an infrared distance-measuring sensor and microcontroller that can be programmed to collect water level measurements at various time intervals. Data are logged by the system in the field and can be downloaded for processing and analysis. This system is not only inexpensive, but also small, lightweight and versatile, and can be readily adapted to collect additional parameters.