I am setting up a control/monitoring system for my small plant nursery using several Arduinos and a central Rasperberry PI.
The idea is that the Arduinos will have sensors and relays connected to them and the Arduino sketch will simply drive the hardware and respond to commands issued from the central Raspberry PI.
The user interface will be a web page served up by the central Raspberry PI.
At this point on the bench I have a Arduino Mega with a temperature, humidity and barometric sensor connected and working, a Raspberry Pi communicating with the Arduino via usb cable and a web page displaying dynamically the Arduino sensor data.
Now it is time to desperate the two replacing the usb cable with a wireless link.
The max distance between the Arduino and Raspberry pi will be about 40 meters with one brick wall in the way.
To the question can the group recommend which Xbee modules I can use for both the central Raspberry Pi and remote