Grove Capacitive Water Sensor fails to work after power cycle

I recently purchased two of the Grove capacitive water sensors I will use them to measure the amount of water in a small tank used for watering plants.

Upon testing they work great, but when you unpower the device and then power it again - the sensor returns zero. The device is working and responding to I2C calls, but it is not returning the correct value. To make it work, I have to take the sensor out of the tank, wipe it with a dry cloth and then it will start measuring correctly.

Both the sensors I purchased work exactly the same. If I unpower them, they no longer show the correct value.

This basically makes the sensor useless to me and for anyone that had hoped to build this into an unattended system? Did you not test this before starting to sell it?

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I am sorry that we did not consider the case of power failure when we were designing. I have fed back your information to the r&d department and hope it can be solved later. @Jensa

@ Baozhu is the source code available somewhere? If so, I could take a look at solving it myself?

@Baozhu any update? Is the sourcecode public?

@Jensa Sorry, I forgot to reply you. I will find out the source code and send it to you immediately @Jensa There you go

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Hi, i just discovered the exact same problem. Did you solved this problem, or do you have any solution?

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Sorry @Vach. I’m just using this for a personal project, so I have not been able to set aside time for it. Hopefully, @Baozhu can do it.

Thats ok, thx for reply. I am just a little bit pissed off, because i need to measure water level in my bachelor project and i dont have time to find alternative… I hope this will have solution, because otherwise as you said, this sensor is useless for unattended system

I actually lecture Embedded Systems at a uni here in Oslo, Norway. Based on how I teach, I would say that this is not really a problem @Vach. You cannot be blamed for non-working hardware, so just present the paper as if the sensor is working? Then make a note in your paper that you have discovered a bug in this device. If someone grading your project, he/she will likely not encounter this bug. If they do - it’s great that you’ve made a note of this, so he/she will know how to work around it.

I know, sorry @Jensa , i could have tested this sensor sooner, so it’s mainly my fault, now i am under time pressure, This is not only bachelor project, I was hoping it would really work, not just theoretically (or at least for to 14 days), so i could use it on my home. The topic is design and implementation of home irrigation system. But if I will not figure out an alternative today, i have no choice and I will be presentating theoretical not fully tested solution :frowning:.

Same problem here, bought 3 of them … if they were working I would buy hundreds…
Will this issue be solved soon?
Does anyone know any alternatives (which is also based on capacitive sensing)?

I have made a bash script to convert raw i2c data into % value for raspberry pi if someone needs it:

Any update @Baozhu? Based on what @Michael says, it really looks like you could make good money on fixing this bug?