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Bar30 Pressure Sensor Not working

(Giridharan) #1

We have recently bought a Bar30 Pressure Sensor, and using the arduino code given in the support, we tested the sensor. The sensor in not working in the water, it stops respond once moves from air to water, it is mentioned the sensor is water proof at 300m depth, but it not working under water at all. Please give us possible solution, otherwise tell us the process of returning the sensor.

(Rusty) #2

Hi Giridharan,

Interesting. Can you tell me more about your setup? Is it mounted on an enclosure?

Are you using a logic level converter between the sensor and Arduino?



(Giridharan) #3

Hi Rusty,

I did not use any logic level converter between the sensor and arduino. We did not have the exact connector that came with the sensor, so we removed the connector and soldered an extension connection wires. Will that create a problem ?? We made sure we insulated the connections perfectly. Still the sensor is not working in water.

(Rusty) #4


Okay, it’s fine to remove the connector but you do need to use a logic level converter since the Arduino operates on 5V and the sensor is not 5V tolerant. I think this is probably the cause of your issues.

Here is a logic level converter that would work well: https://www.sparkfun.com/products/12009

Does it work as soon as you pull it out of the water?



(Giridharan) #5

But it the sensor is working fine (without any logic level converter) when it is outside water . What could be the problem then ?

(Jacob) #6

Are the wires leading into the sensor touching the water? The i2c bus capacitance is increased by the dielectric properties of water. Higher bus capacitance leads to higher rise and fall times in the signals, and degrades communications. This can be exacerbated by the fact that the sensor may be compromised (damaged) because you have been using 5V signals. If you continue using 5V signals, the sensor will likely stop working at all at some point.

If the wires have been touching the water, try keeping the sensor outside of the water, and just dipping the wires into the water to see if this is the issue. But you should get a logic level converter before you continue using the sensor.


(Rusty) #7


In our experience, the sensor will operate at 5V for a period of time but it will be damaged eventually. Even when it is working, it becomes much more sensitive and frequently stops responding.

I would strongly recommend using a logic level converter before you continue testing.


(Giridharan) #8

Thank you guys, I have ordered an logic level converter, let me see if that fixes the problem and i will let you know. Thanks again.

(Giridharan) #9

Hi Rusty,

The Depth Sensor is working perfectly fine with Arduino, but due to size constraints we are planning to interface the sensor with Raspberry Pi 2 so that we don’t need to use the logic level converter. Are there codes and libraries available in Raspberry Pi as you have in Arduino ?


(Jacob) #10

The MS family of pressure sensors all have the same I2C commands, and similar calculations. Here are some libraries I found:

For MS5611:

Python: https://github.com/jfosnight/jonahsystems/tree/master/python

C: https://github.com/jfosnight/jonahsystems/tree/master/python

And for MS5803:

You will need to multiply the pressure readings these return by a scalar. If I remember correctly, for the ms5611 libraries, multiply by 40, and for the MS5803 libraries, multiply by 4.