Hi. I'm concocting a game-based project which will involve up to 8 individual Arduino Nanos, placed within a few feet of each other on a table, all communicating with each other wirelessly. They will need to pass fairly basic information back and forth, perhaps once or twice a second, changing the state of LEDs based on user input on each of the devices. Not all 8 units would necessarily be used at the same time - anywhere between 2 and 8 would be in use at a time.
Those little transmitters and receivers are great fun, and you should try the VirtualWire library.
However, they operate on only one channel and will interfere with each other. So, to have multiple communications pathways you must pass short messages that in addition to any data, identify the transmitter and intended receiver. Each receiver has to be programmed to respond to only messages intended for it. The messages also require some sort of error-detecting capability (already built in to VirtualWire) in case of message collisions and other interference.
Radioblocks do look perfect, but I also can't find anywhere to buy - the links to the shop are dead.
Cost is an important factor for me, which is why the devices I've bought are so intriguing. I could be building each unit for £10-15 – perhaps considerably less if I built my own controller. That prohibits things like the Xbee.
It sounds like I could do this with these devices with a central base station. That base station could poll each of the devices in turn, await a response with any updates on user input, then send back instructions to change the state of the LEDs. I guess the speed at which this could happen with eight slave devices would be the determining factor - any more than a second per update would make it too clunky.
I'm going to test out the extremely cheap eBay approach in a few weeks time, with 2-3 slave devices and one master, to see how practical it might be as an approach. Will report back...