Im just about to start playing with talking between multiple arduinos over a wireless link. I think, from the things I have read that the xbee units in API/packet mode will do everything I want but they're a little on the expensive side for a newbie and certainly for a proof of concept project.
In short I need something that is:
a) cheap :) b) simple to use c) provides a good reliable connection d) allows mutliple arduinos to talk to each other e) supports ACK for data recieved
Point B is critical as I am very new to this :)
Point C is not so important right now but would be for a finished product.
For point D, the arduinos dont really have to all be able to communicate with each other as long as multiple slaves can communicate with a master and the slaves can recieve an ack from the master but it would be nice to have two way comms across all of the connected arduinos.
Any help greatly appreciated.