On 4 Apr 2013, at 10:27, Mike Stirling wrote: > In this example, what is the Arduino if not a gateway? Arduinos may be gateways and/or they may be slimmed down and running on 2xAA cells strapped to a valve. RPis and other mini-Linux are likely only to be gateways, but have thousands of times the memory and performance and storage and so on. Rgds Damon