# Irrigation controller functions



## Sandi (Apr 3, 2018)

I'm making simple controller and I'd like to know on your experience, which functions are mandatory, useful or maybe unnecessary.

I have:

1. wifi controlled unit

2 web and mobile app interface

3 soil moisture probe

4. temperature probes in soil at, 2 and 4 inches under surface 
- from minute to year graph, 
- freeze alarm (drain system), 
- freeze irrigation skip, 
- decision first app pre emergent, 
- decision when to hot for fertilization, last fert in year, 
- lawn behave vs. temp....

4. cumulative valve open time in minutes (water consumption statistics) and reset

5 valve schedule

6. WiFi signal strenght

As I can read, rain forecast is not such a useful feature? If there is condition to skip irrigation only if forecast is 1 inch or more, would that be OK?


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## Sandi (Apr 3, 2018)

Development public dashboard can be seen here:
https://cayenne.mydevices.com/shared/5d9bb16240d9ab10063771dc/project/f0d81d43-47e5-47b9-bffc-3e3062ddfde1


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## jayhawk (Apr 18, 2017)

Confidence in chance of rain as a threshold. +++

Is this personal or mass market?


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## Sandi (Apr 3, 2018)

Personal, based on open IoT platforms.


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## g-man (Jun 15, 2017)

@Sandi do you know about open sprinkler?

https://github.com/opensprinkler


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## Sandi (Apr 3, 2018)

g-man, yes I noticed. My hardware costs me 15-20 USD.

One interesting fact, while watching Ryan, Doc or LCN about soil temperature:
I have two permanent temp probes in the soil. First 2 inches and second 4 inches deep. The difference between temp probes -2 and -4 inches was max 1.8 °F . -2 inch probe reading was higher or lower in cold night or warm sunlight. Daily difference was about 7.2 °F . Conclusion, it is more important when to measure (in the late afternoon or early in the morning) than how deep. The soil has a daily temperature fluctuation and does not change slowly throughout the month.


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## Sandi (Apr 3, 2018)

I'm thinking of adding a short-term watering feature in the stress heat.

Current status:
icon 1: soil moisture sensor - dry or moist
icon 1 and 4: manual valve of/off, weekly schedule
icon 3 and 5: actual valve status, open or closed, activation valve 1 deactivates valve 2 and vice versa
icon 6: 24 hours rain forecast
icon 7 (slider): threshold; if 24h rain forecast is bigger than slider, do not irrigate
icon 8: soil temp 4 inch deep
icon 9: soil temp 2 inch deep
icon 10: air temperature 
icon 11: WiFi signal strenght
temperature graph soil temp sensors
temperature graph air temp


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## Sandi (Apr 3, 2018)

There are useful features as triggers. Here is a trigger, if rain forecast in next 24 hours is bigger than 10 mm (0.4 inch) send me email. This feature can be used, for example, when is the optimal time for next fertilization or overseeding.


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## dhmeiser (Sep 18, 2019)

For your soil moisture probe I hope you are not using one of those cheap bi-pin probes, found on eBay and such. those usually last about 3 weeks.

if you are gong to use an inexpensive probe get one which is capacitive or a gypsum based one. 
Either way they both will need to be calibrated based upon your soil and re-calibrated each year. 
Lastly they will need to be replaced on a regular basis

You may want to look at this for suggestions for a wireless one which could be made to run on solar 
https://www.instructables.com/id/Wireless-Soil-Moisture-Sensor/


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## Sandi (Apr 3, 2018)

I'm using Gardena Soil Moisture Sensor. https://www.gardena.com/int/products/watering/water-controls/soil-moisture-sensor/900898601/
Gardena is probably biggest Europe company. From their web page is text: _The Soil Moisture Sensor durably and electronically measures the temperature differences in the soil, and derives the moisture of the soil from these - precise and reliable._



I'm learning how reliable the precipitation forecasts are. The graph shows how gradual the forecast increased to 1.75 mm. The actual measurement from the nearest weather station shows 5.6 mm of precipitation.


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