@Poldi I know it is not a best practice open you front door through http call without encryption, in my mind i have this 2 solutions:
- embed a passowrd in each request and arduino will check it, but it always goes in clear...
- set a MAC address filter on your router plus WPA-PSK2 key it should be quite safe
if anyone has a best idea I'm here!
@Arduino-Idea I'll do it no problem, could you provide me a little sketch about to read data from DS18B20? I don't have it here and I can test the code but, if you have time, you should do it 
EDIT
I forget a piece, tha "Send data to remote server" is used to upload automatically data read from sensors, the result is this
I'm looking for a cheap RoR hosting now