A low-cost, three-dimensional and real-time marine environment monitoring system, Databuoy with connection to the internet

The monitoring of environmental parameters of Hong Kong waters has usually been achieved by accumulating collected data from single point sources just below the sea surface, once or twice a month by the Hong Kong Environmental Protection Department. There has also been some experimentation involving data loggers placed on the seabed. However all of the above data collecting methods produce only historical datasets months or even years before such data is processed and made available. For a timely response to changing environmental conditions, it will be important that the data is received and processed in real-time if there is going to be a quick remedial action to changes. City University has developed a low-cost system, Databuoy, for collecting basic marine environmental parameters. This system is equipped with up to 10 sensor packs suspended in different depths in the water column under a floating buoy. Each sensor pack measures a physical parameter such as temperature, salinity or light intensity. All sensors, under each buoy, are connected to a single multiplexer that is in turn connected to a PC via a simple MODEM connection. The DataBuoy I system consisted of a single buoy with a string of sensors underneath it. The more advanced configuration, DataBuoy II, connect several nearby DataBuoys together for a 3-D representation of the measured parameters to be constructed from the data. The system has four basic components, that is, the supporting structure, the sensor packs and two levels of signal multiplexing and transmission units. Connection to the internet and other systems are then possible via this connection. The application for this type of system extends beyond the collection of field data. Real time water parameters exceeding warnings, data processing involving the rate of change of parameters and the control of marine area polluting equipment or discharges via closed loop feedback connections are all possible.