What about using evapotranspiration for choosing watering amount?

[lucadealfaro]

I just got an opensprinkler, and I am generally very happy — but I see that it uses the Zimmerman method for adjusting watering according to weather.
There has been a lot of work on evapotranspiration, and there are formulas that allow to approximate watering needs on the basis of things like temperature during the day, wind, cloud cover, humidity, etc. Is there work going on to implement evapotranspiration for the opensprinkler?
If it can be useful, some time ago I had worked out the formulas. I would be happy to share them with someone who knows how to implement them in the firmware. Is there interest? I hope I can still find my formulas, or else, I will have to re-derive them, but is there interest (= is there someone who is interested in putting them in the firmware if I code them e.g. in Python)?

[ShawnHarte]

Search for penmon monteith eto on the forums, I made up a script a while back for handeling the python/server side and a hack to make it work with 2.1.4 firmware. I have personally made an effort to recompile the firmware, for having it run internally, but I don’t want to release it publically for fear it may brick someone’s hardware because they believe it is plug and play ready. If you are interested in testing knowing it may ruin your unit I can email the firmware to you.

[Ray]

It’s on our todo list to incorporate the ET-based algorithms that the forum users like ShawnHarte contributed. Just haven’t had time to get there yet.

[lucadealfaro]

Great, I did not know that code/algorithms were already contributed. Can I see what ShawnHarte contributed?
I would be very grateful for a pointer.

[ShawnHarte]

Here is the link to the files posted

Hope that helps

[hplato]

Hi Shawn, did you manage to upload the new code that you were working on?

Also, would it be OK to use this code as a reference and refactor it in another language? I’m not familiar with python, but if it was in perl I could use it in my home automation setup to push the correct watering times.

[ShawnHarte]

You can do anything you wish with the code, please note portions are directly copied from other contributers on the forums here, and external libraries are used, so please respect their work and leave credit where credit is due. I have not uploaded the firmware changes yet, as I bricked one controller with it. I was able to recover it after a couple days of trial and error, but I really would prefer not to leave others in the same situation. I have very little time to mess with my own, I more than likely would be unable to help others.

Honestly the concept is to take everything program related in the nvm and move it to the sd card. Then use the python script to work in a manner similar to the Zimmerman method.

[Author]

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