Sprinkler Control - Best practices?

Interesting. I am already invested in the rachio system. The Spruce system is exactly like the rachio with the addition of the realtime soil moisture sensor - which illustrates what I am looking for - the supplement of hyperlocal weather intelligence with soil moisture sensors. Thats what rachio is missing. I was hoping I could find something similar with zwave or zigbee or even wifi - going through hubitat.

If you wanted some DIY fun..

(you can also use your PI for soo much more of course).

You could add a maker api call to that python script that sets a virtual switch that turns on when wet / off when dry.

Update: Just bit the bullet and am going to give it a shot.. I already have a PI on hand. Also bought extended sensor cables though I'm not sure how they will hold up outside. With a slight script modification you can add more sensors to the PI.. maybe have a virtual button group or something via Maker. Another thought is to make it available via a RESTful interface (I use Node) and create a custom driver.

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Thanks for pointing me towards this - I am actually thinking of going this route by using a z-uno and Adafruit Stemma Soil Sensor.

My son dabbles in this stuff so thinking of making it a small home project for him - we even discussed 3-d printing an enclosure for all this. Will keep you posted.

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That looks interesting too! The sensors I linked to are very inexpensive - I got 5 for less than $9. The trick is being able to extend the wiring from the sensor to the unit. I found this (if it helps any):

https://www.trossenrobotics.com/p/phidgets-12-foot-sensor-cable.aspx

If you are just looking for a way to tell if the moisture level at a certain depth is there or not I wonder if extending the prongs on a water leak sensor would work. Put the sensor inside a small waterproof plastic case. I used this one to house a d/w sensor for a mailbox.

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And ruin a perfectly good DIY project?!?!? :wink:

I think one of the issues is the soil will start to degrade any in ground sensors so it might be better to have cheap replaceable ones.

I also have one of these on hand...

The adafriut sensor seems to solve this problem:

Most low cost soil sensors are resistive style, where there's two prongs and the sensor measures the conductivity between the two. These work OK at first, but eventually start to oxidize because of the exposed metal. Even if they're gold plated! The resistivity measurement goes up and up, so you constantly have to re-calibrate your code. Also, resistive measurements don't always work in loose soil.

This design is superior with a capacitive measurement. Capacitive measurements use only one probe, don't have any exposed metal, and don't introduce any DC currents into your plants. We use the built in capacitive touch measurement system built into the ATSAMD10 chip, which will give you a reading ranging from about 200 (very dry) to 2000 (very wet). As a bonus, we also give you the ambient temperature from the internal temperature sensor on the microcontroller, it's not high precision, maybe good to + or - 2 degrees Celsius.

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Why would you want two systems controlling the watering though? Why wouldn't you get a sensor that connects to Rachio so that it can control it all by itself. If the soil is very dry but there's a major rain event an hour away, you really don't need hubitat watering your plants, do you?

You are absolutely right. That is the better route to take - a sensor that talks to rachio directly and enables rachio to use that data together with its weather forecast data, They call it bypass scheduling. However Rachio seems to support only wired and expensive sensors (with very detailed wiring setup) - toro soil sensor and RAIN BIRD SMRT-Y Sensor

The DIY setup we discussed above will cost much less and perhaps much simpler to setup. But you are right that it doesnt take into account the immediate weather forecast. Would have been great if I can tie the DIY stuff into rachio.

Also rachio seems to advocate the use of sensors, in addition to their weather intelligence feature:

Many lawns have multiple micro-climates that they need to account for; from south-facing and full sun to north-facing with a slope, a mesh network of sensors is the best approach for a true closed loop feedback of your lawn's health.

I am also not sure "bypass scheduling" is really the solution to my problem. Rachio describes their bypass scheduling as

Bypass scheduling is similar to that of a rain sensor; it interrupts the common wire and prohibits the controller from watering.

It only interrupts watering? vs watering a specific zone when its soil moisture level is dry ?

but you might be able to use something like APIXU for that..

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@erktrek So you are thinking that with the DIY setup, I could also add this weather data into the "trigger" process in hubitat ? Water the zone if soil moisture level is less than X and there is no forecast of rain in the next 6 hours or so ? Something like that? How is integration of weather data into hubitat? easily done?

I'm not sure I'd have to look at it a bit - probably look at APIXU's attributes and tie it in using RM - haven't looked at the forecast stuff yet so not sure how it's reported.

You can also check with the developer @bangali for advice as well.

That APIXU driver is also good for illuminance checking etc for things like automated exterior lighting instead of just sunrise/sunset.

edit: Looking at the driver code there is a "percentPrecip" attribute. So you could do a comparison like you were thinking maybe, uncertain how far out that goes.

edit2: so I think exposing that attribute you may have to use another app by @bangali called WATO

[RELEASE] WATO - When any Attribute Then this cmd Otherwise that cmd

You'd use this (I think) to set a virtual switch when the chance of rain crosses your threshold.. then in RM you'd compare the moisture sensor + chance of rain switch and act accordingly.

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The APIXU is not integrated as a trigger in RM. And you cannot add custom conditions or triggers to RM, only custom actions. That is why I said it would be very difficult to replicate the Rachio architecture.

That is true but you can the use WATO app (see above) to access those attributes and set a virtual switch or something which is what makes that app cool...

And if you can figure out how to do that, be my quest. LOL. How are you going to account for all of the different possibilities in a forecast? Rachio is a system designed to do this. You aren't going to be able to replicate that with Wato and RM. If you could, everyone would and Rachio wouldn't be in business.

Don't get me wrong - I believe that you should use smart devices the way they are intended instead of trying to recreate the functionality in HE. I do this with my Nest thermostats.

I do not own the Rachio and am interested in playing around with these easy/inexpensive moisture sensors for my small garden. I've successfully used a solenoid valve + smartplug to control my simple watering system.

Well, yeah....if you don't need a Rachio, then they're no need for them. Plus, I'm sure if your garden is a little over watered, it's no big deal. But if you're watering an entire lawn and you're paying a premium for water....well, that's Rachio's key demographic.

:grin: - My watering last year was timed, had it kick off an hour before dawn. Have large containers with tomatoes etc. Worked out really well rain or shine. This year I may see if I can't optimize the water usage a bit with the sensors. I do have a hookup for a proper lawn irrigation system - I prefer the Rain Machine but other expenses have gotten in the way first. In NJ there is almost the opposite issue to a drought.

Overwatering is not a good thing for vegetable gardens either. With ST & WebCoRE I was able to incorporate a rudimentary control based on time and forecast. Did not have rain or moisture sensors though which would have been nice.

Run my question about the need to take into account, potentially, different micro-climates in every garden - should we water a specific zone if it gets too much sun and dries up more often than the others? Here is what I got from Rachio support :

you are correct in assuming that we do not have soil moisture sensors water when they get dry, rather we have them not water when they are wet. Our flex daily schedule archetype does track moisture levels and precipitation to monitor and decide if a zone is dry enough that it could be irrigated responsibly.

for a simple switch sensor without anything major, the rachio should be able to handle a DIY sensor. Most sensors just either break or complete a circuit depending on certain moisture parameters, and we are only compatible with normally closed sensors.

The comment about how sensors interact with rachio directly is the reason why I think triggering the zone to water via hubitat is a better option. The incoming signal from the sensor is a simple reading of soil moisture levels. I think its far easier to use a hubitat rule to trigger the zone watering in this case. thoughts?

So for overall landscape irrigation I would say leave the smart stuff to Rachio.

For specific use cases - like small garden areas, depending upon plant type etc I think HE could be a very flexible way of controlling the watering. The only thing is you might end up bypassing the irrigation system.