Low-cost drifting buoys for surface water observations in wetlands

Low-cost technologies are needed in developing and least-developed countries to improve monitoring capabilities to determine the dispersion characteristics of inland and coastal waters. Thus, the objective of the paper is to describe the design and construction of a low-cost saucer-shaped drifter, including its internal electronics, remote-control unit, and software. The system can operate over short timescales and distances and is thus suitable for estimating dispersion coefficients and differential kinematic properties of the fluid. The drifter was constructed primarily from readily available plastic products. The main electronic components were a global positioning receiver, microcontroller, lithium-polymer battery, wireless communication module, and activation and battery status indicators. The electronic design simplifies operation because the stored positions can be transferred to a computer via a mini-universal serial bus port without having to open the buoy. In addition, communication between the control unit and saucer-shaped drifter and its memory enhances its operational capability in the field. Water tightness tests were successful, and the operation of electronics was tested at a wetland known as Estero Topila, México, to infer dispersion characteristics using a trio of drifters. Agreement with the Richardson’s 4/3 power law provides reliability of the electronics system performance and measured data.