Author Topic: Moteino Based Sprinkler Controler  (Read 16126 times)

TomWS

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Re: Moteino Based Sprinkler Controler
« Reply #15 on: November 06, 2014, 06:08:28 PM »
I agree with Felix, there are plenty of these modules on eBay (even on Amazon), just look for "Buck switching".  The modules are small, reliable, efficient, can take up to 35V DC input, and support up to 3A output.  The output is usually adjustable from ~3V to input-2 volts or so...

Tom


ColinR

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RGrandall

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Re: Moteino Based Sprinkler Controler
« Reply #17 on: July 22, 2015, 07:12:13 PM »
Mine has a rain sensor but I think soil moisture sensor would make more sense.
Any suggestions on a sensor that would work? I already have this soil moisture meter and was wondering if it would feasibly work or not. It's extremely low power and seems to be pretty durable. I suppose that I could get a new sensor, but I always like being frugal where I can... Thanks for the help/input.

thinkpeace

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Re: Moteino Based Sprinkler Controler
« Reply #18 on: July 24, 2015, 05:51:02 PM »
RGrandall,

I made my own soil moisture sensor that works great and is inexpensive to make.  It measures the effect of the surrounding soil on the capacitance between two metal rings. 

There are cheap sensors that measure conductivity and how-to's on making conductivity type moisture sensors on the internet.  The conductivity is effected considerably by the amount of minerals in the water & soil in addition to the soil moisture, so it is not very accurate.  Measuring capacitance works much better, and is how the Vernier soil moisture sensor works.

I used this circuit: http://forums.adafruit.com/viewtopic.php?f=25&p=88077

To make the sensor, I used a 14" sprinkler riser pipe, and put two rings of conductive 1/2" copper tape around the pipe near the bottom end.  The rings are separated by about 2 millimeters. 

I drilled a small hole between the two metal rings. 

Then I soldered 24-30 gauge wire to the rings and fed it through the holes and out the bottom end of the pipe. 

I covered the entire pipe except for the pipe threads with shrink tubing.

I made a small 555 timer circuit which goes inside the pipe and soldered the wires from the rings to the circuit.  The rings are the capacitor being measured in this circuit .   I made a custom PCB for this, though originally I used an SMT breakout board with an SMT 555 IC: http://www.adafruit.com/products/1212. Be sure to use a 555 timer that works at 3.3V.

Three wires run from the circuit up through the opening on the other end of the pipe, into a box containing a Moetino: 3.3V, Gnd and Signal.

I closed up the bottom of the pipe with a threaded end-cap.

I calibrated it using a Vernier soil moisture sensor ($95) as a reference.  The manual for the Vernier sensor also has instructions on how to calibrate their sensor.  These instructions could be used to calibrate any soil moisture sensor: http://www.vernier.com/files/manuals/sms-bta.pdf.

It's been working great, and is in my garden now.   The information from my sensor is published to a web-server, so I can view data from anywhere.  The data goes to a Rapbery-Pi Gateway, and from there is sent to the web-server .

TomWS

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Re: Moteino Based Sprinkler Controler
« Reply #19 on: July 24, 2015, 06:45:38 PM »
Interesting.  I've heard of using capacitance before but haven't seen a circuit.  Do you know (approximately) what the capacitance range is?  Or, alternatively, what timing resistors and resulting frequency range is?

When you said you run the wires from inside to the bottom of the riser, but then wire to the 555 circuit inside the riser, I have to admit being confused by this.  Wouldn't you just keep the wires inside the pipe?

Finally, do you place the riser horizontally or vertically and how deep are the copper tape bands?

Thanks for posting, I'm always looking for a reasonably accurate moisture sensor.

Tom

thinkpeace

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Re: Moteino Based Sprinkler Controler
« Reply #20 on: July 25, 2015, 12:17:08 AM »
TomWS, 

I used the same resistors and capacitor as shown in the schematic, http://forums.adafruit.com/viewtopic.php?f=25&p=88077.  This seems to work well for the soil moisture sensor.

I run the wires from the rings out the bottom of the pipe, and 3 wires from the top of the pipe to the bottom of the pipe.  Then I solder the wires coming out of the bottom of the pipe to the PCB, and push the PCB into the riser pipe, so nothing is coming out of the bottom.  Then there are three wires coming out of the top of the pipe.  These connect to the moteino.  The 1/2" riser pipe can thread into an outdoor outlet box.

I place the riser pipe vertically in the ground about 10" deep.  It's a 1/2" x 14" or 18" pipe.  You'll want it to be in the root zone of the plants.

I'm thinking of making one with multiple sensors on one pipe, to measure moisture at different depths.

TomWS

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Re: Moteino Based Sprinkler Controler
« Reply #21 on: July 25, 2015, 10:17:40 AM »
TomWS, 

I used the same resistors and capacitor as shown in the schematic, http://forums.adafruit.com/viewtopic.php?f=25&p=88077.  This seems to work well for the soil moisture sensor.

I run the wires from the rings out the bottom of the pipe, and 3 wires from the top of the pipe to the bottom of the pipe.  Then I solder the wires coming out of the bottom of the pipe to the PCB, and push the PCB into the riser pipe, so nothing is coming out of the bottom.  Then there are three wires coming out of the top of the pipe.  These connect to the moteino.  The 1/2" riser pipe can thread into an outdoor outlet box.

I place the riser pipe vertically in the ground about 10" deep.  It's a 1/2" x 14" or 18" pipe.  You'll want it to be in the root zone of the plants.

I'm thinking of making one with multiple sensors on one pipe, to measure moisture at different depths.
Ok, makes sense now.  Thanks.

Here's the circuit I've used for years (http://emesystems.com/pdfs/SMX.pdf - I made my own and didn't use their module) and has been reliable but the Watermark probe is expensive ($35++).  Given its construction, it's relatively immune to minerals in the ground water however.  Note that the circuit is not open hardware licensed.   Personal use ok, sharing isn't...

I use the frequency counter library: http://interface.khm.de/index.php/lab/interfaces-advanced/arduino-frequency-counter-library/  to monitor the frequency due to moisture.

I also added a DS18B20 temperature probe tie wrapped to the Watermark probe because the Watermark probe does need temperature compensation.  Does yours?

I've added this circuit to my latest Moteino based Sprinkler Valve (https://lowpowerlab.com/forum/index.php/topic,1046.0.html) so I have a single control point for monitoring and irrigating a zone.

Thanks for posting,
Tom
« Last Edit: July 25, 2015, 11:03:26 AM by TomWS »

thinkpeace

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Re: Moteino Based Sprinkler Controler
« Reply #22 on: July 25, 2015, 01:35:05 PM »
TomWS,

The Watermark circuit is probably based on one in the public domain.  Here I found the almost identical circuit elsewhere: http://emesystems.com/OL2mhos.htm.

I'm not doing any temperature correction.  The temperature does have an effect on the measurement of capacitance.  The correction depends on the characteristics of the soil.  One method of calculating the correction factors is by looking at the change in measurement of capacitance along with changes in temperature as the sun rises.  The idea is that as the soil warms in the morning, the amount of moisture will change very little. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3444127/

Maybe some day I'll have time to write a function to do the calculations and correct for temperature.  If you should implement something like this, please post it to this topic :-)

Eric






TomWS

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Re: Moteino Based Sprinkler Controler
« Reply #23 on: July 25, 2015, 02:07:31 PM »
The Watermark circuit is probably based on one in the public domain.  Here I found the almost identical circuit elsewhere: http://emesystems.com/OL2mhos.htm.
Well, I wouldn't assume that the owner of that circuit (who is the same as the PDF I referenced) is freely licensing this circuit for commercial purposes since there is no explicit statement to that effect.
Quote
Maybe some day I'll have time to write a function to do the calculations and correct for temperature.  If you should implement something like this, please post it to this topic :-)
Will do. 

Tom

EloyP

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Re: Moteino Based Sprinkler Controler
« Reply #24 on: July 26, 2015, 10:30:51 AM »
For a while I have been keeping an eye on an open source sensor by a guy in Lithuania that uses capacitive humidity sensing. I have not used it yet but I am planning on getting one in the near future. What I like about this sensor is that the author has done a lot of experimentation and research, and his product is being sold on sites like Tindie and Adafruit with good reviews. The project's home page is:

http://wemakethings.net/chirp/

The "Moisture sensing" section has a link to a detailed blog post of how his sensor works:

http://wemakethings.net/2012/09/26/capacitance_measurement/

The "History" section gives an idea of how much effort this guy has put into designing this sensor.

Note that the Chirp is a plant watering alarm. However, the author also sells the standalone sensor for a little bit less:

https://www.tindie.com/products/miceuz/i2c-soil-moisture-sensor/

This sensor has an I2C interface but based on the project's Github repository (https://github.com/Miceuz/i2c-moisture-sensor) the author seems to be working on sensors with analog and RS-485 interfaces.

Cheers,

Eloy Paris.-

TomWS

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Re: Moteino Based Sprinkler Controler
« Reply #25 on: July 26, 2015, 02:56:58 PM »
I think you should get one! Maybe two.  By Fall!   ;D

Tom

EloyP

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Re: Moteino Based Sprinkler Controler
« Reply #26 on: July 26, 2015, 03:50:51 PM »
I think you should get one! Maybe two.  By Fall!   ;D

Yes indeed! Seems like a good compromise (cost-wise) between the Vegetronix VH400, the WATERMARK and DIY  :)

Cheers!

luisr320

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Re: Moteino Based Sprinkler Controler
« Reply #27 on: July 29, 2015, 08:28:23 AM »
some.  i re-did the 8x triac driver board to take in I2C, thinking that would make it more flexible.  one could add an I2C keypad, or more boards and connect it to a moteino over i2c.  anyway, i can restart that soon i think, and more importantly start work on the software.

here's the link to the shared board project...
https://oshpark.com/shared_projects/Ic23AFof

also i'm in california and stopped watering due to drought.  looking forward to a el-nino winter though and hope to see some changes soon.

Hello Merge.
Somehow this topic drifted to a soil moister sensor and your project got buried a couple of messages back.
As I understand your idea, there will be a board with the moteino to connect to the ones you made available on Oshpark.com (https://oshpark.com/shared_projects/Ic23AFof).
Did you continue your work on this board? And what about the software part? Any new developments?