Author Topic: Smart Solar Wireless Irrigation System (another one :-)  (Read 3588 times)

Adrián

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Smart Solar Wireless Irrigation System (another one :-)
« on: February 22, 2016, 12:15:25 PM »
Hello, my name is Adrián, and I have been working on irrigation system modules with arduino (AC Version) for some time [1], and now I am trying to continue this develop with the wireless version. Looking different microcontroller to be used, the moteinos fits well with the functionalities the device needs to run, and because of that we have built our first PCB design using them. Right now I have the concept idea, a couple of PCB built (where I already detected a bug :-), and not yet any code lines written. I saw there are other similar projects to develop irrigation process, and this is my own approach of a smart irrigation system that I would like to share, and this is the place for it.

In coming posts I will add more information about diagram process, agronomical functionalities, etc.

Greetings.



[1] Background: https://ecommerce-aisur.org/sac/wiki/index.php/Historia
« Last Edit: March 20, 2016, 04:59:40 AM by Adrián »

WhiteHare

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Re: Smart Solar Wireless Irrigation System (another one :-)
« Reply #1 on: February 22, 2016, 01:17:41 PM »
Looks interesting.  I wish I could read Spanish....  From the looks of it, I take it that your moisture probe measures soil conductivity?

« Last Edit: February 22, 2016, 01:29:56 PM by WhiteHare »

Adrián

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Re: Smart Solar Wireless Irrigation System (another one :-)
« Reply #2 on: February 22, 2016, 03:22:16 PM »
From the looks of it, I take it that your moisture probe measures soil conductivity?

Exactly, we measures conductivity between electrodes, and this parameter is used to obtain an indirect measurement of the soil moisture. In addition to that and to prevent criticisms from agronomists, we have improved this indirect measurement, calibrating the system according to our irrigation water but also using a sample of our soil, this easy process with a 100% saturated sample of soil, allows the system to 'know' the maximum of conductivity (water+soil) that means 100% of soil moisture. We where doing experiments with this calibrated conductivity related to the real soil moisture, weighing the sample, and the correlation was really high r=0,9.
« Last Edit: February 22, 2016, 03:26:21 PM by Adrian »

WhiteHare

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Re: Smart Solar Wireless Irrigation System (another one :-)
« Reply #3 on: February 22, 2016, 03:41:47 PM »
How long does your calibration last?  At least in my experience with trying that kind of probe, there's a need for frequent recalibration, especially during the growing season, as fertilizers are either applied or as they're absorbed by the plants, because very often fertilizers change the soil conductivity.  Even the manner in which you irrigate can change the salinity of the soil either up or down, and rain can have a different effect.

Then, too, unless your probe is stainless steel, you've got the problem of probe corrosion, especially with copper probes like yours, which can also cause loss of calibration.  It's a known problem.  They're cheap and easy to make, and they're simple to understand and use in the short-term, but they just aren't any good for longitudinal measurements.   

Anyhow, for a possible solution that would fit nicely with your project, have a look at https://lowpowerlab.com/forum/index.php/topic,1317.msg9060.html#msg9060  It would be great to hear your thoughts on that thread.  Because of common ground interest, and you're being a serious developer, you might even wish to help move it to fruition.

Regardless, I'm sure Moteino's would be a good fit to accelerate making your project wireless.   :)
« Last Edit: February 22, 2016, 04:37:58 PM by WhiteHare »

Adrián

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Re: Smart Solar Wireless Irrigation System (another one :-)
« Reply #4 on: February 22, 2016, 05:19:13 PM »
Quote
How long does your calibration last?

Well, it depends according to our culture facility, and how homogeneity is our irrigation water, because of that, sometimes there is no recalibration required, let me explain; if we are watering a field with lawn or grass, like in a typical residential house, using regular water, the conductivity will keep quite homogeneous during all the time, having a reasonable proper measurement. But, you are right, if we are adding nutrients to the water, first we have to calibrate the system with these conditions, and if we change again the proportion of the fertilizers, the system will need a new recalibration to have a proper behavior. But imagine that our irrigation water comes from a tank, where we add the fertilizers there, in that case, It could be relatively easy to add a sensor node to the tank, measuring the conductivity and recalibrating the soil moisture automatically.

About the probe corrosion, well, you are right, copper probes are not a good choice, but the fact to be used for our initial prototypes, taught us to increase their longevity, just adding a short term electric pulse for sampling.

Code: [Select]
#define SM_POWER_PIN 2 // Soil Moisture and Field Capacity POWER PIN (ELECTRODES).

https://github.com/Artesanos/SAC-Sistemas-Automatas-de-Cultivo/blob/master/Electronica/1-Canal%20%28Riego%29/Version%20AC/Rev_1.4/Codigo/SAC_1S_AC_1_4/Sensors.h

But in any case now we are using stainless steel (316 A4) probe.


Quote
Anyhow, have a look at https://lowpowerlab.com/forum/index.php/topic,1317.msg9060.html#msg9060  As a serious user, it would be great to hear your thoughts on that thread.
Sure, let me have a look first  :)

Adrián

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Re: Smart Solar Wireless Irrigation System (another one :-)
« Reply #5 on: February 23, 2016, 01:57:01 PM »
My opinion after reading this topic https://lowpowerlab.com/forum/index.php/topic,1317.15.html, is:

1.- The only point to use a Capacitive Soil Moisture Sensor like this https://www.dfrobot.com/wiki/index.php?title=Capacitive_Soil_Moisture_Sensor_SKU:SEN0193, vs. a Resistive Soil Moisture Sensor is to avoid the corrosion of the electrodes, idea that I like, but according to our experience, using the stainless steel (316 A4) probe with an electric sampling pulse, it works also really fine. As an example of that, we where using this probe for a long term experiments during months, sampling constantly (with this pulse) and no signs of corrosion where observed. In this case with this wireless version, we will reduce drastically the sampling frequency (let's say a pulse per  hour), so I am sure the probe will survive for many years. Is true that I would like to explore a Capacitive Soil Moisture Sensor 'in the future', but probably right now according to our results we will go ahead with the method already tested with good results, and there is always possible to improve the system just changing slightly the circuit to be adapted for a capacitive soil moisture sensor.

2.- The tensiometers of course are the best option for real soil moisture measurements, but in the other hand the price is high.



Update*****

Checking more carefully your post, WhiteHare, I re studied the WATERMARK Soil Moisture Sensor that you said  — MODEL 200SS http://www.irrometer.com/pdf/sensors/403%20Sensor%20%20Web5.pdf , and yes, I think It could be a good candidate, and it should be interesting to know about the output reading, but for sure it could be easily implement, probably also without changes in the circuit :-)
« Last Edit: February 25, 2016, 03:37:46 PM by Adrian »

Adrián

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Re: Smart Solar Wireless Irrigation System (another one :-)
« Reply #6 on: February 23, 2016, 03:16:42 PM »
In these images I show the circuit block proposed.


« Last Edit: March 17, 2016, 06:52:27 AM by Adrián »

Adrián

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Re: Smart Solar Wireless Irrigation System (another one :-)
« Reply #7 on: February 25, 2016, 03:47:24 PM »
I show in these models the design of the devices.

Here the Smart Irrigation Solar Sensor Node:



Here the Smart Irrigation Solar Remote Actuator:


« Last Edit: March 17, 2016, 07:12:07 AM by Adrián »

Adrián

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Re: Smart Solar Wireless Irrigation System (another one :-)
« Reply #8 on: February 27, 2016, 01:10:07 PM »
This is the communication protocol proposed, where:

- the Red waves represent the communication between the radios of the moteinos (Sensor Nodes and Remote Actuator), and the information transmited is mainly to develop the agronomical tasks.

- the Green waves represent the communication between any smart phone with the Remote Actuator via wifi, using the ESP8266. This will allow the configuration and the control of the system offline, where no Internet connection is required.

- the Blue waves represent the communication between the Remote Actuator and a Router connected to the Internet, and this optional connection will allow the configuration and the control of the system online, via a web server.

« Last Edit: March 18, 2016, 06:41:03 AM by Adrián »

Adrián

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Re: Smart Solar Wireless Irrigation System (another one :-)
« Reply #9 on: March 17, 2016, 06:47:31 AM »
This is the Sensor Node Funcional Block Diagram Proposed:

(coming soon the Remote Actuator Block Diagram)