Mobile phone based drifting lagrangian flow sensors

Mobile phone based drifters offer distinct advantages over those using custom electronic circuit boards. They leverage the inexpensive and modern hardware provided by the mobile phone market to supply water resource scientists with a new solution to sensing water resources. Mobile phone based drifters strategically address in situ sensing applications in order to focus on the large scale use of mobile phones dealing with communications, software, hardware, and system reliability. We have demonstrated that a simple design of a drifter built around an Android phone robustly survives many hours of experimental usage. In addition to the positioning capabilities of the phone via GPS, we also use the accelerometer of the phone to filter out samples when the drifter is in storage. The success of these drifters as passive mobile phone sensors has also led us to develop motorized mobile phone drifters.