Duke Robotics - AUV Overview

Pressure Sensor

Charybdis uses an onboard WL400 pressure sensor manufactured by Global Water Instrumentation to provide water pressure information. The Pressure sensor's cable is attached to a Subconn underwater connector that feeds into the electronics tube. The DC/DC converters provide the pressure sensor with +12V. The DAC reads in the input voltages from the pressure sensor (across a 250ohm resistor) and converts the voltage into a depth rating (in meters). The pressure sensor reads 0.5V at sea level, and the output voltage rises as the sensor is submerged below the surface (reading 4.5V at 25PSI, or about 17 meters). The pressure sensor provides an essential feedback mechanism for the AUV's navigation. The onboard computer constantly reads depth information from the pressure sensor to ensure that the vehicle does not drift upward or downward as it tries to travel in the XY plane. As soon as the depth reading exceeds the specified tolerance, the center thruster will rotate and bring the vehicle to its appropriate Z coordinate position.