A True Soil Moisture Sensor: SHT20

A True Soil Moisture Sensor: SHT20

June 28, 2019

A True Soil Moisture Sensor: SHT20

There soooooo  many company designed kits called “Plant-Hydration-Kit”, such as the https://www.smart-prototyping.com/Zio-Plant-Hydration-Kit-v1  , but the most Significant features is that they all have a “soil moisture sensor” in their product/kit…. Like this:
Soil Moisture SensorOr this:         Capacitive Moisture V2.0


But, I want to ask all this vendors, do you have used this kind of module relly , to test the soil  moisture,  while try to watering them?
What i have tested for this kind of “soil moisture sensor” is :
ugly bad……


1.The sensor output bad.. the output data either high, or low, or unstable…. For example,  In the air It can be 100, while a finger touch 500, while in dry soil 300, if a little water touched, 500. it changes a lot depends on how deep  you dig it into the soil….

2.No water-poof… it is impossible that you can avoid some water touch them , and the whole board got useless , and even short the VCC to GND… burn the whole system. This is high risk even this “Plant-Hydration-Kit” a kit for maker.


So, in a real water kit, an industry leave soil moisture is necessary. Which I suggest the SHT20
https://www.makerfabs.com/soil-temperature-and-humidity-sensor-sht20.html

                                                                 Soil Moisture Sensor SHT20
It’s output stable, and water-proof.

I tested the module with Maduino, with the library of SHT20. Connect it to Maduino with A4/A5, and the VCC/GND:

Maduino UNO Board by MakerfabsLibrary of SHT20


In the air, the output humidity and temperature really good:
                                                    SHT20 Testing Result of Air


And then insert it into the soil, in 10s, the output data get stable, and reliable, no matter how deep you dip it into the soil:
SHT20 in the soil The output:    SHT20 Testing Result of Soil

I try to put some water around the sensor, the output data changes Continuously, without any jumping… which is reasonable.

The metal case also proof waters in, which ensures the sensor works OK with rain:

                                               SHT20 is working well in the plant

The sensor works good in the rain…~ this makes the kit a really working
smart plant watering kit