Question 1

Could you submerge the moisture sensor fully in soil if all connections are adequately protected?

Accepted Answer

I put conformal coating and heatshrink on them and had no problems with soil immersion. I  calibrate the sensors in water (100% moisture), and dry air (0% moisture) because there is lots of variation sensor to sensor in both offset and gain.

Question 2

What are the measurement units? Centibars?

Accepted Answer

You need to calibrate the units in code.  More details here.  https://wiki.dfrobot.com/Capacitive_Soil_Moisture_Sensor_SKU_SEN0193

Question 3

What is the average power consumption per reading?

Accepted Answer

I don't know the answer, but it is pretty low. If interested, for the price buy one and see if it suits your needs. I use mine in a handheld device and only power it up when I need a reading. I am using a Raspberry Pico and running it off of a 9-volt battery reduced to 5 volts.

Question 4

What library do I need for a raspberry pi?

Accepted Answer

You don't need a library, just need to read the analog pin,A0.

This is what I use:

// Calibration: SOIL_AIR is reading when dry, SOIL_WATER is reading when submerged in water about 3/4 up the stick
// Used to calculate a 0-100% range based on the readings
#define SOIL_AIR 362
#define SOIL_WATER 637

int get_soil_readings(int n)
{
    int a0 = 0;
    for(int i=0; i<n;i++)
      {
      int raw = analogRead(SOIL_ANALOG);
      Debug << "Raw Reading: " << raw << "
";
      raw = max(SOIL_AIR,raw);
      raw = min(SOIL_WATER, raw);
      Debug << "MinMax'd Reading: " << raw << "
";
      a0 += raw;
      delay(5);
      }
    int reading = a0/n;
    float percentage = (reading - SOIL_WATER) * 100.0 / (SOIL_AIR-SOIL_WATER);
    return int(percentage);
}

ASIN	B07H3P1NRM
Best Sellers Rank	#33,443 in Patio, Lawn & Garden ( See Top 100 in Patio, Lawn & Garden ) #48 in Soil Meters
Brand Name	Gikfun
Customer Reviews	4.2 4.2 out of 5 stars (243)
Item Dimensions	0.91 x 0.01 x 3.86 inches
Item Weight	22 g
Manufacturer	Esooho
Model	EK1940
Mounting Type	Tabletop
Number of Items	2
Output Type	Analog
Part Number	EK1940
Specific Uses For Product	garden watering, outdoor use
Style Name	Modern
Unit Count	2 Count

Gikfun Capacitive Soil Moisture Sensor Corrosion Resistant for Arduino Moisture Detection Garden Watering DIY (Pack of 2PCS) EK1940

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