Grove - Capacitive Moisture Sensor (Corrosion-Resistant)

Dear users,

I would like to ask some questions.
Firstly, I would like to ask about range of output value of the sensor. Generally, i would like to know what is maximum output value (when the sensor is in the water) and minimum output value (when the soil is dry) of the sensor. For example for classic sensor (Grove Moisture Sensor) maximum value is 950, when it’s in the water and 0 when the soil is dry. But i’d like to use Corrosion-Resistant for my own project.
Secondly, i would like how i should understand “If the you uses Arduino UNO as the motherboard, it is recommended that use the DC power supply. Otherwise, the maximum ripple of VCC may exceed 100mV”. Actually, i use Arduino Uno, and i would like to as if it means that i should just power my Arduino by AC/DC adapter (7-12V)?
I’m looking forward to receiving your answers.
Best wishes, stay healthy.

Hi @xSwistak
The range of the output value isn’t listed at the NE555DR Datasheet, it is influenced by many factors.
Yes, it means that you should power your Arduino with AC/DC adapter (7-12V).


There are several topics about the values for the Capacitive Moisture Sensor (corrosion resistant), but no answers at all.
Is it useless?

My values are:

  • no water: around 760
  • in water: around 530

Thanks for helping :raised_hands:

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I contacted support since i didn’t got any answer in the forum. The reply was the same given in another forum post:

The result you got is right, it is an error of the wiki result. The wiki needs to be modified.

But no further update since, even after i asked again for an update.
Indeed it seems that we bought some useless stuff.

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I ended up calibrating the sensor myself, using the values I get when emerged, and dry.
From there I used the map function:

int max = 760;
int min = 530;

int moisture = = analogRead(sensorPin); 

int percentage = map(moisture, min, max, 0, 100);

But I’m not sure if the measure is relevant at all.

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The problem is that i have different values than yours, so this seems to be all over the place. I’ll try to calibrate my two sensors in the real conditions expected, starting this weekend.

I will keep you posted.

I have to add that this lack of support from Seed Studio on this simple matter is making me consider the use of the Grove ecosystem altogether because it is supposed to be a solution to simplify integration. But in the end, without support and with this kind of errors it is useless as an ecosystem.

After seven days of logging i cannot make sense of this data. Sensor 1 is out in the air, Sensor 2 is in a bucket with dirt that i watered. After seven days the “moister level” keeps going down. I’m still waiting for an analog measurer that i ordered from Amazon for real data comparison.


Hi all,
I was trying to figure out how this sensor works as well. In that proces, someone suggested that, based on the circuit on the page of this sensor, that the capacitor used as the sensor can basically not discharge. I assume this would make the sensor at least slow? Has anyone tried to tweak the sensor?