Integrating Bar30 depth/pressure sensor into ArduCopter

Hello everyone,

My project team is working on integrating a Bar30 Depth/Pressure Sensor onboard a custom-designed/built cycloidal propeller unmanned underwater vehicle. The sensor is connected to one of the I2C ports on our CUAV V5+ flight controller. While the UUV’s firmware is built from a modified version of ArduCopter V4.3.6, we ensured that the ArduSub code for handling the Bar30 (AP_BARO_MS5611.cpp) is located in the AP_Baro library of the ArduCopter code.

After testing the UUV in a 4.5 ft. pool and collecting some pressure data, the result was the following (data log reviewed from within Mission Planner):

To say the least, something is awry! I am currently unsure whether the pressure value being displayed is a reading of the absolute pressure (in which case, this would be quite incorrect) or a difference in pressure compared to atmospheric. Furthermore, I am assuming that the pressure units are in Pascals (as stated within the AP_BARO_MS5611.cpp file). I am also unsure why the pressure readings oscillate in this manner rather than being a more continuous line.

Overall, I am wondering if this is an issue relating to the calibration of the sensor or something more involved with the ArduCopter firmware that we will have to modify in order to get the Bar30 operational. Thanks in advance for any feedback/assistance!

Hi @JonathanLep717, welcome to the forum :slight_smile:

Sounds funky - I’d love to know more about the vehicle if you’re able to share more :slight_smile:

Where is this stated? I couldn’t find such a statement.

How fast are the fluctuations, and is the sensor bobbing in and out of the water?

I took a brief look and there was nothing jumping out as an obvious cause. Have you tried getting an altitude measurement instead of looking at the pressure measurements? It might also help to try running ArduSub just to make sure the sensor is ok.