Soil Tensiometer Sensor Network
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I'm presently using soil moisture sensors that measure soil conductivity, which might be OK if I never fertilized my lawn. However, when I do fertilize, it seems to gradually affect conductivity, and the measurements lose calibration. Definitely not ideal.
Apparently each method has its own limitations, but I'd like to try capacitance and see if it maintains calibration better.
Most likely someone out there has already solved this using an arduino, or with a simple circuit connected to an arduino to get the required accuracy. These guys seem close to an answer like that: http://zerocharactersleft.blogspot.com/2011/11/pcb-as-capacitive-soil-moisture-sensor.html
Based on that discussion, it appears that high frequency is required to avoid salinity (such as from fertilizer) throwing off the readings.In any case, there seems to be a loose consensus that 80Mhz is the fright frequency (e.g. http://www.surechem.com.my/products/901003-100105-PDF.pdf)
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or you have the other way around: Infragram DIY Plant Analysis Webcam
http://store.publiclab.org/products/infragram-diy-filter-packAs the vegetronix, I have in RFX433 the Imagintronix soil moisture sensor: http://www.imagintronix.co.uk/shop/4587637347/soil-moisture-sensor-check-water-level-in-your-pot-plants/9163185
This is already quite useful to see water propagation in a 2x2 kitchen garden.
z-wave - Vera -> Domoticz
rfx - Domoticz <- MyDomoAtHome <- Imperihome
mysensors -> mysensors-gw -> Domoticz -
or you have the other way around: Infragram DIY Plant Analysis Webcam
http://store.publiclab.org/products/infragram-diy-filter-packAs the vegetronix, I have in RFX433 the Imagintronix soil moisture sensor: http://www.imagintronix.co.uk/shop/4587637347/soil-moisture-sensor-check-water-level-in-your-pot-plants/9163185
This is already quite useful to see water propagation in a 2x2 kitchen garden.
@epierre said:
or you have the other way around: Infragram DIY Plant Analysis Webcam
http://store.publiclab.org/products/infragram-diy-filter-packDoesn't work. I've been down that path already. In actuality, it mainly just tells you if your grass is alive or dead. That's because dead grass doesn't have chlorophyll and isn't green. You'd get the same results looking at a color picture and noting how green or brown it is. Checkout http://www.publiclab.org/profile/WhiteRabbit and the follow-up discussion in those posts.
You could try looking for other indicators of grass stress. For instance, grass does change color the drier it gets. If you have the skills, you might try measuring that. It might be a fun science project, but in the end it's going to be more complicated and expensive. However, it also changes color based on fertilization, so that's going to throw off your calibration.
As the vegetronix, I have in RFX433 the Imagintronix soil moisture sensor: http://www.imagintronix.co.uk/shop/4587637347/soil-moisture-sensor-check-water-level-in-your-pot-plants/9163185
This is already quite useful to see water propagation in a 2x2 kitchen garden.
I'm pretty sure that one isn't capacitive but actually measures resistance. Take a look at the probe near the tip. Do you see exposed metal contacts, or is it all sealed up? Pull it out and have a look. I'll wager you'll see two small metal pads near the tip, and it's along that gap between them that soil conductance is being measured.
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In that case technology is your friend. :smile:
Regarding # of soil probes and depth, I'm finding that the deeper one is probably the most important, at least for established turf. You can keep the upper layer fairly moist by watering for too short a time, and interestingly, the water never makes it very far down. Here we have clay soil, and it may be different for sandy soil. Here the result is that the roots at the deeper layers keep pumping the water out, and it just gets drier and drier at the deeper layer. It's invisible: you can't know that from just looking at things or feeling the top of the soil. In fact, without a soil probe (or a shovel) I don't think there's any way to know that such a thing is going on.
On the other hand, most grass roots are shallow, and if push comes to shove, I'm not sure to what degree deeper watering saves water or is a waste of water. I think it might save water, though, because the shallower soil is more prone to evaporation. The standard advice seems to be to water infrequently, but deep.
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Not sure what you mean.
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@neverdie 2'' and 4'' are pretty close in depth (unless you put them horizontally, not vertically).
in international units that makes 5, 10 and 20cm depths, my sensor is already 8 cm in height.
z-wave - Vera -> Domoticz
rfx - Domoticz <- MyDomoAtHome <- Imperihome
mysensors -> mysensors-gw -> Domoticz -
@neverdie 2'' and 4'' are pretty close in depth (unless you put them horizontally, not vertically).
in international units that makes 5, 10 and 20cm depths, my sensor is already 8 cm in height.
@epierre said:
@neverdie 2'' and 4'' are pretty close in depth (unless you put them horizontally, not vertically).
in international units that makes 5, 10 and 20cm depths, my sensor is already 8 cm in height.
At present, I'm undoubtedly using a different sensor than you are, and I mounted it horizontally at the depth indicated, not vertically, if that's what you're doing. At the time I installed it, my goal for each sensor was just to measure soil moisture at a given depth, not across depths.
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@NeverDie have you gone to use the EvapoTranspiration calculus such as described below (example in the second part after the theory)
z-wave - Vera -> Domoticz
rfx - Domoticz <- MyDomoAtHome <- Imperihome
mysensors -> mysensors-gw -> Domoticz -
@NeverDie have you gone to use the EvapoTranspiration calculus such as described below (example in the second part after the theory)
@epierre said:
@NeverDie have you gone to use the EvapoTranspiration calculus such as described below (example in the second part after the theory)
I haven't. It would be a great help if there were a free library that worked with generic weather station gear. It would seem that Davis has a non-free library that works with their particular weather station gear, but aside from that, I don't know of much else.
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Also looking at soil moisture probes, either https://www.tindie.com/products/miceuz/i2c-soil-moisture-sensor/ which is based on the chirp one. Just need to seal the sides, or otherwise http://www.aliexpress.com/store/product/Soil-temperature-and-humidity-sensors-SHT10/1773013_32356151782.html
Is anyone using the SHT ones ? (hopefully no pun intended) :)
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@Lawrence-Helm sht10 are expensive and are sensible to humidity, they are thus not made to stay in the ground or water.
the soil humidity need to reach the captor but this one is not meant to support being in a too high humidity environment.
Otherwise they are good ones
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@epierre the SHT10 that I put a link to has the following statements:
- Can be completely submerged.
and
- Usage:The probe can be directly embedded in the soil
Also the following link: http://www.adafruit.com/products/1298
Are your thoughts still the same, before I bite the bullet :)
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read the description:
"but it's always best to avoid long-term (over 1 hour at a time) submersion, if you need something that can be submerged for over an hour you may want to find a different sensor. "
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@Lawrence-Helm I've got a collection of them and looked at their assembly, clearly don't trust the ill traducted or too much over-selling descriptions when you put electronic in a very humid environment
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@epierre Hi...it is ameasing your work!! :D
I am wondering about Mq-135. We have troubles with reading differents gases.
From the datasheet we read the slopes
Gas X" X0" "Rs/R0 "Rs/R0 pendiente (log y- log y0)/(log x-log x0)"
Air 200 10 3.6 3.6 0.00000
co 200 10 1.3 2.9 -0.26783
nh4 200 10 0.79 2.7 -0.41024
c02 200 10 0.8 2.4 -0.36673
3/4/ 200 10 0.72 1.9 -0.32391
1/4/ 200 10 0.64 1.5 -0.28432
+- 200 10 0.59 1.4 -0.28845these data are in the next worksheet https://docs.google.com/spreadsheets/d/18Z6XyxwXVsWdMIk9vbUuCucaLJDdmR0QUFSTYG79ftw/edit?usp=sharing
¿may you share with us your code for this sensor in order to see your slopes and Rs/R0 values taken from the curve?
¿do you know the meaning of the name go gases with 3/4 or 1/4 or +- ?thank you in advance
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following this thread loosely.
I have the following sensors and they seem to be accurate to some degree:
and they are much easier to work with Arduino compared to Watermark stuff. Anyone agree?
