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Bar30 Pressure Sensor Communication Failure


(Fletcher) #1

Hi BR,

I recently purchased a Bar30 Pressure Sensor from your store, and have set about connecting it to an Arduino Mega 2560 to test the readings using the example code posted on the BR github.

Similar to this topic I am getting similar values, indicating that there is some connection issue in my circuit or a communication failure in I2C (See attached serial readout). The readings do not fluctuate as would be expected with normal sensor noise, and temperature does not respond to gentle heating of the sensor with a hair dryer.

I’ve attached a photo of my circuit. Connections in the 4 Pin header are soldered to the Bar30 wires. The logic level converter is shifting from 5V-3.3V correctly, here are the pin voltage diffs on the Bar30 side:

  1. Vin - Gnd -> 3.32V
  2. SCL - Gnd -> 1.78V
  3. SDA - Gnd -> 3.29V
Am I missing something critical, or is the sensor faulty?

Cheers,

Fletcher




(Adam) #2

Hi Fletcher,

I agree that the numbers you are seeing definitely do not seem right! Those values are consistent with an I2C communication failure, I believe that there may be a problem with the logic level converter you are using. According to the Sparkfun product page, that model was discontinued for not properly stepping down 5V to 3.3V signals properly. You can confirm this with an oscilloscope, the peaks should reach 3.3V in a square wave. The likely faulty converter should be replaced as soon as possible to avoid any possible damage to the Bar30, our I2C Level Converter will work well.

-Adam


(wdodo) #3

hi adam
my data is
Starting
Pressure: -1609.00 mbar
Temperature: 333.38 deg C
Depth: -26.82 m
Altitude: nan m above mean sea level
Pressure: -1611.00 mbar
Temperature: 333.38 deg C
Depth: -26.84 m
Altitude: nan m above mean sea level
Pressure: -1612.00 mbar
Temperature: 333.38 deg C
Depth: -26.85 m
Altitude: nan m above mean sea level
Pressure: -1611.00 mbar
Temperature: 333.38 deg C
Depth: -26.84 m
Altitude: nan m above mean sea level
Pressure: -1611.00 mbar
Temperature: 333.38 deg C
Depth: -26.84 m
Altitude: nan m above mean sea level

so whai is wrong about my data


(Jacob) #4

Hi @MMMMK,

We have recently updated our library to check for errors at the beginning of the program, but this has not made it’s way to the version that you download through Arduino. Please download this compressed library, then unzip it and put it in your libraries folder to replace your current MS5837 library. Please run the example provided in this library, and let us know what the output is.

-Jacob