Home        Store        Docs        Blog

Bar02 is not showing any readings

(Mitransh Choubisa) #1

I have purchased a Bar02 pressure sensor and I am using it for depth calculation in our ROV. I am trying to test the sensor with a Arduino UNO and i am running the example sketch given on Blue Robotics website. There is a weird problem that i am facing, after uploading the code in Arduino when i check the serial monitor i am not getting any data. I have also purchased a Celsius sensor from Blue Robotics and it is working fine and i am getting proper readings both under water and above water. We are a team of second year engineering students trying to build a ROV, please help us out with this issue.

(Patrick José Pereira) #2


Are you using logic level converter between the sensor and the Arduino ?
The Bar02 sensor uses 3.3V I2C, and the arduino output is 5V.

(Mitransh Choubisa) #3

Hi Patrick,
Well actuall I am not using logic level converter, but i am using 3v3 pin in arduino for power pin.
Is this actually causing the problem?

(Patrick José Pereira) #4


Yes, that can cause the problem and can damage the sensor.
The arduino microcontroller has 5V I/O and the sensor is 3.3VI/O and can accept a power supply up to 5.5V.
You can check that in the learn tab in the sensor page.

You can read more about that here:

(Mitransh Choubisa) #5

Thank you so much, yes this is the problem.
But one more thing, i hope this is not a case with Celsius sensor.
Will I need to use a logic level converter with it as well?
It is working fine right now, I don’t want to put it to risk as well.

(Patrick José Pereira) #6


Both sensors uses 3.3V I/O as you can see in the documentation.
If the sensor is connected in a 5V I/O microcontroller, and works, it can be damaged after some time in this condition.

(Mitransh Choubisa) #7

Thank you so much. I’ll surely keep it mind. This was really helpfull.

(Mitransh Choubisa) #8

Also please tell me if i am connecting Bar02 with Pixhawk, will i have to use the logic level converter for interface between pixhawk and the sensor? I am asking this because the Pixhawk provides 5v on the I2C power line as well.

(Patrick José Pereira) #9


Again, as the documention says here.

The sensor communicates over I2C. It operates on 3.3V I2C voltage but can accept power input up to 5.5V. It comes standard with a 4-pin DF13 connector that is compatible with most DroneCode compatible boards including the APM2.6, PixHawk, and others.

A tip for an engineer student, the answer usually is in the documentation.

(Mitransh Choubisa) #10

Thank you so much, sir. All these was really helpful.
I’ll keep the tip in mind.