New Current Measurement Technology USGS needs to measure current in shallow water regions where there are large oscillatory currents generated by surface waves. BASS uses acoustic technology and is therefore less affected by fouling than the savonious rotor. Like many other sensors on the market, these output frequency or voltage signals proportional to the environmental parameter being measured. The Tattletale 6 has an eight channel analog to digital converter and a single period count circuit that are software controlled. Multiple sensors with frequency output are accommodated by adding an eight channel multiplexor to the front end of the period count circuit.
Software is used to address the individual channels.
Tattletales provide up to 200 MB of hard disk storage to accommodate output from high frequency sampled hardware such as the BASS system and pressure sensor. An advantage of this instrument is that it does not depend on telemetry for complete retrieval of such a large data set. Although all have the same sensors, hardware, software subroutines and data formats, the components are combined differently in each system to best fulfill scientific objectives. The system and its sensors are mounted on a tripod frame that is deployed in 30 meters of water. The two current sensors are 0.4 and 1 meters above the sea bed.