@Oitzu Well, What I want to do is; Make gateway my controller ( intend to use arduino yun), the reason for that is none of the controllers fit my need, which is I want to automate hydroponic greenhouse and it is something like this ; https://www.youtube.com/watch?v=-IfvbrZJ4sY
I want to ask again " How do I pull data to use in my controller code in gateway instead of forwarding to Raspberry PI. Can you help me with a simple code showing how it can be done?".
