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
Brand Name	Gikfun
Customer Reviews	4.4 4.4 out of 5 stars (244)
Item Dimensions	23 x 98 millimeters
Item Weight	22 Grams
Manufacturer	Gikfun
Maximum Supply Voltage	5.5 Volts (DC)
Model	EK1940
Mounting Type	Freestanding
Number of Items	2
Output Type	analog
Part Number	EK1940
Specific Uses For Product	Garden plants, Moisture detection, Intelligent agriculture
Style Name	Modern
Unit Count	2.0 Count
Upper Temperature Rating	50 Degrees Celsius

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

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