Hi to everybody,
I have written a c++ code that run on an ESP8266 as a OpenSprinkler master/controller !
Hart of the code is a computation based on Penman ET method on the amount of irrigation required to be compared to the actual OS watering schedule.
I have found this thread very interesting and I would like to discuss some of the issues I have encountered writing my code:
First and most important getting good weather data, to be used for ET calculation, like sun radiation values that are difficult to get from WU stations. Using monthly average data as well as evaluating sun rad. from other parameters doesn’t lead to good results.
I understand that your calculations are based on cloud coverage forecast and you derive from that the hour of sunshine value to be used in calculations.
I think that since ET water needs are only relevant to future irrigation will be better to use actual data.
Second is how to account of different kind of vegetation and ground coverage and seasonal as well as how to account for water runoff and percolation.
Third have you foreseen any possibility to use local sensors?