Industry grade soil moisture sensor

Thread Starter

sairfan1

Joined May 24, 2012
77
Which soil moisture sensor you use for industry grade project? I'm looking for with at least 3% accuracy and low power project (3.3-5v)

I tried to search some on mouser and digikey but did not find something that i can use
in general search i was able to find some most of them are a complete product not specific sensor

rather than experimenting on different sensors, i was looking for to take advantage of one's experience
thanks
 
Last edited:
Which soil moisture sensor you use for industry grade project? I'm looking for with at least 3% accuracy and low power project (3.3-5v)

I tried to search some on mouser and digikey but did not find something that i can use
in general search i was able to find some most of them are a complete product not specific sensor

rather than experimenting on different sensors, i was looking for to take advantage of one's experience
thanks
I have a problem with completely understanding the question. Help me out: what is accuracy for a soil moisture sensor (3%)? I'm not being provocative, I am being quite serious. If we speak of a humidity sensor that measures relative humidity as a percentage, we can understand what we are describing as accuracy within +/- 3%. How do you translate that to soil moisture? The percentage of the soil that is water, based on weight?

What is industry grade?

Take a look at the work of this guy. It's quite old now, but he did a very good job, is freely sharing his work and some have taken it and maretted it as "their" product.

Here is something at the opposite end, so to speak. https://www.ebay.com/p/Soil-Humidit...ensor-Module-DC-3-3-5v-T1/1787038571?thm=1000

How would you define soil moisture? In what units?
 

Thread Starter

sairfan1

Joined May 24, 2012
77
Sorry guys, we hobbyist often ask very stupid things, let me decode my question

yes, by 3% i meant +/-3% accuracy, if soil moisture is measured in different unit can you please advise? (i go through some datasheets and felt that reading unit is in percentage)

Industry grade: link you provided to ebay has a pcb based sensor that does not work for a long time, may be i should say professional? as definitely those ebay sensors are not used in industries and i believe industry grade sensor will give reliable reading for long time.
 

Thread Starter

sairfan1

Joined May 24, 2012
77
I was reading it here looks good article, i will definitely read more about it once i getting started and having parts,

I was looking for help to choose parts so that i start working with appropriate sensor/method, for example just reading about sensors i came to know that those pcb based sensors are not good choice, being hobbyist its really hard to manage time to work on a project, just wanted to reduce that time so that at least i start working on right direction
 

Audioguru

Joined Dec 20, 2007
11,248
I fixed a soil moisture measuring circuit that did not work. But to simply measure the conductivity of damp or dry soil is not accurate:
1) Pure water (distilled) does not conduct.
2) There are many different kinds of salt in soil and each one and its amount affects the conductivity a lot. Soil fertilizer is a salt.
 
I had a soils class in college and I don't mean in any way to discourage you but your +\- 3% may or may not be useful for what you're attempting to do. As suggested already, the accuracy of a sensor is determined in a lot of different ways. Just measuring conductivity between probes based on a voltage drop without considering the soil chemistry may result in data that may or may not serve your needs. What is it you're trying to accomplish and are there characteristics or limits to your data logger that will effect your choice of sensor(s)?
 

BR-549

Joined Sep 22, 2013
4,928
I agree. Much more info is needed before any recommendations. What exactly are you doing. There is no universal solution.

Edit: Is this going to be used in industrial soil?
 

Thread Starter

sairfan1

Joined May 24, 2012
77
I want to do experiments on farm's soil, I'm further reading about parameters that should be considered
I also did general search for available sensors but surprised that i was not able to find any source that is expert/developing sensors for such applications, though there are some complete applications but i don't know what is their source for sensor may be they developed it at their own.
 
I want to do experiments on farm's soil, I'm further reading about parameters that should be considered
I also did general search for available sensors but surprised that i was not able to find any source that is expert/developing sensors for such applications, though there are some complete applications but i don't know what is their source for sensor may be they developed it at their own.
I'm surprised you can't find anything. There are a lot of them available. It's been a long time but I do remember having to do a soil analysis to calibrate the sensors to. Knowing the ratio of organic to mineral content and mineral component make up was necessary. This determined soil conductivity for sensor calibration. We had to use a statistical basis for mapping sensor layout and soil analysis was required for each sensor location.
 

Alec_t

Joined Sep 17, 2013
12,724
Two lengths of stainless steel rod/wire are commonly used as soil moisture probes and would probably be the most durable material readily obtainable at low cost.
 

Audioguru

Joined Dec 20, 2007
11,248
Nowadays even acid rain conducts electricity a lot. My tap water conducts. Pure distilled water does not conduct. No water (dry soil) also does not conduct. You need a different way to measure when soil is damp or dry.
 

MisterBill2

Joined Jan 23, 2018
11,547
There are companies that sell moisture meters. I think that Grainger sells them. I would not consider an internet source because they can vanish as fast as a deleted file if the product does not work.
The calibration is indeed a big challenge.
Probably a good place to start research is looking at "soil moisture Measurement".
 
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