Automatic irrigation system using pic microcontroller

I am not acquainted with the pic microcontroller, but i have made an automatic irrigation system for my olive tree with only a few components:

You only need the following componets:

- 1 5v 1A DC power supply

- 1 12v 1A DC power supply (https://www.kjell.com/no/produkter/elektro-og-verktoy/stromforsyning/stromforsyning/ac-dc/fast-utgangsspenning/ac-dc-stromadapter-12-v-(dc)-12-w-p44382)

- 1 soil moisture sensor (https://www.kjell.com/no/produkter/elektro-og-verktoy/arduino/moduler/luxorparts-jordfuktmaler-p87941)

- 1 100 ohm 1/4w resistor

- 1 10k 1/4w resistor

- 1 30 ohm 1/4w resistor

- 2 1n4148 diodes

- 1 IRF520N MOSFET (https://www.kjell.com/no/produkter/elektro-og-verktoy/elektronikk/halvledere/transistorer/luxorparts-transistor-mosfet-irf520-5-pk--p90630?gclid=EAIaIQobChMIrsPMzIbh1gIVxLUYCh2xUAiqEAQYASABEgJWSfD_BwE)

- 1 VR05R241A single pole DIL relay (https://www.kjell.com/no/produkter/elektro-og-verktoy/elektronikk/electromechanics/releer/1-polet-dil-rele-5-v-dc-0-5-a-30-v-p36110)

- 1 pump (https://www.kjell.com/no/produkter/elektro-og-verktoy/elektronikk/electromechanics/motorer/luxorparts-vaeskepumpe-peristaltisk-p90782)

Another suggestion for a full blown irrigation system based on the Arduino is well documented in "Make: Getting Started with Arduino" (https://www.amazon.co.uk/Make-Electronics-Prototyping-Publisher-Paperback/dp/B00SLUYAS4/ref=sr_1_3?ie=UTF8&qid=150746740… )

Good luck!

I have finished testing my design and have concluded that it should not be used. It is not stable. I cannot find any documentation for the moisture sensor that i have used with specifications for the D0 output pin, but it appears that it is a bad choice for controlling the circuitry i built around it. I have tried different variations of circuitry to control with the D0 output pin, but have been unable to get them to work reliably. My latest attempt is based on the A0 output pin input to the A0 pin of an Adafruit Feather HUZZAH, and that solution appears more promising (although i did not want to have to use anything so extravagant). This latest attempt is still being tested and i do not plan on repeating my previous mistake of publishing detailed information about it before it is fully developed and tested - and certainly not unless someone expresses an interest in it.

Thank you for the words of encouragement Matt, John, and Paul! I believe the point all of you are making is a very important one - something i first began to grasp while taking an online FutureLearn course called "Prepare to Run a Code Club".

The people presenting the course shared some of their experiences running code clubs. One of those was about what happened when they asked the children in a club if there was anything special they wanted to do. Some of the children wanted to have a club event where their technology challenged parents could attend in order to better understand what they were doing. On the night they implemented this suggestion one of the parents was very discouraged and disappointed when his attempts to complete a project failed. But his son had a remarkable response to the situation. He said: "But dad, you have just learned something important - that this approach was not quite right. You should look at it that way and try another approach towards a solution." (or something along those lines).

I was truly amazed! Could this be an important difference between people who fail and those who are successful in life - the ability to accept that it is ok to err if we choose to perceive it as a learning experience rather than some kind of failure as a human being?

Anyway, i will publish my latest attempt shortly (after dinner).

Thank you all.

>I have finished testing my design and have concluded that it should not be used. It is not stable.

Sorry to hear about the hurdles you're running into. However, these projects are often like puzzles - some more difficult than others - and part of the challenge can be just trying to work out the bugs

Interestingly, I just noticed this on the element14/Farnell/Newark store:

http://canada.newark.com/global-specialties/gsk-947/edu-kit-automatic-sprinkler-controller/dp/75X8167

"The  GSK-947GSK-947 is an automatic sprinkler control kit This kit is used to control the water pump for watering plants automatically It measures the soil moisture in 3 levels with delay time controls the time of watering and adjusts the watering according to soil moisture "

At $20 CAD it's a pretty good deal too.

It might also help you figure out the design of it, as it's a build-it kit. Here's the PDF tech specs.

Also @Akash for your project.

-Nico

The moisture sensor module looks like one of these LM393 comparator based sensor modules.

Module schematic:

https://www.modmypi.com/download/moisture-sensor.jpg

LM393 data sheet:

https://www.modmypi.com/download/lm393.pdf

There is a similar looking project using that module both with and without a microcontroller here:

http://electroschematics.com/12065/arduino-soil-moisture-sensor-module/

Cool! Thanks for the tip Nico - maybe i will take a closer look at it later on, but i would like to continue with the solution i am working with for a while in order to gather more knowledge about a lot of things i am wondering about. My present solution appears to be working satisfactorily and i have a few ideas for making it better (for example sending me messages when problems occur). I guess it could be perceived as overkill to use an Adafruit Feather HUZZAH ESP8266 for something as banal as this, but then again it only cost me £23.50 (shipping included) and it has quite a few advantages over a hardwired solution. It has built in wifi and it is programmable with quite a bit of I/O that i can use to connect sensors and actuators and control them - and i do see a few future possibilities that i find interesting (for example: sending me status messages if assistance is required).

-raymond

Interesting. I am quite sure that the one without an arduino will have the same problems that i was experiencing (i have done quite a bit of experimenting with different solutions of that type and believe that the D0 signal from the soil moisture sensor can be very unstable resulting in problems controlling the relay). At this point in time i am not really interested in pursuing that line of investigation further though. The solution i am working with at present is performing quite well and has spawned new ideas that i plan to pursue.

Thank you though!

-raymond

>I guess it could be perceived as overkill to use an Adafruit Feather HUZZAH ESP8266 for something as banal as this

I was thinking of using a Digistump Oak (similar to Huzzah I think), just to check pond water levels, heh. It's the wireless and web-based part that really makes life easier. I supported his Kickstarter, and haven't really used it since originally trying it out.

That said, there's something about building circuits that do not use a microcontroller that adds to the fun of the challenge too.

-Nico

Yes, very likely.

Adding a hysteresis resistor to the LM393 comparator circuit should have tamed its D0 switching behaviour for driving the relay though e.g.

http://www.ti.com/lit/ug/tidu020a/tidu020a.pdf

Thank you Dave,

Been racking my mind trying to remember that work (hysteresis) - it's been at least 30 years since i last used it (studied electronics in the 70's and have not been very active with it the last 3 decades)! Am quite sure that is the problem.

Yes, i agree with you Nico, but unfortunately i am not very talented and have lots of things i am interested in and not enough time to touch on a fraction of them - so i have to make some difficult decisions about prioritizing. I love programming passionately and its attraction can be too great for me to resist .

Am quite sure that is the problem.

Adding hysterisis to the relay will help stop it destroying itself.

This is one of the biggest advantages of adding any form of controller BUT it can be achieved by capacitors, resistors and a dose of imperical derivation.

I have an organic Irrigation controller ... my wife turns on the sprinkler for her garden.

Mark

Am quite sure that is the problem.

Adding hysterisis to the relay will help stop it destroying itself.

This is one of the biggest advantages of adding any form of controller BUT it can be achieved by capacitors, resistors and a dose of imperical derivation.

I have an organic Irrigation controller ... my wife turns on the sprinkler for her garden.

Mark

Thank you Mark,

I do believe that you are right. I have used hysteresis via code in the version of this project that i posted yesterday - among other changes that i have implemented. All testing so far appear to indicate that everything is working as planned and expected.

Congratulations on your organic irrigation controller !

- raymond

ludo ergo sum!