Disclosed is a floating sensor system having a casing that encloses a microcontroller. The microcontroller includes a digital processor and a non-volatile memory. The casing also encloses a data bus that connects the microcontroller to an external environment sensor, an RF transceiver, and a battery....http://www.google.de/patents/US8134462?utm_source=gb-gplus-sharePatent US8134462 - Self-contained sensor package for water security and safety
