I have a Uno-R3 (w/ Wi-Fi and Relay Shield) for my little project. I would like to get a Due, but seems that Wi-Fi library is not yet ready (I can use Ethernet Shield for now).
However, I am not sure whether there is any Relay Shield works w/ Due. I have this 4-channel Relay Shield: (http://www.amazon.com/4-Channel-Relay-Shield-for-Arduino/dp/B007JOEVNW/ref=sr_1_5?ie=UTF8&qid=1378770573&sr=8-5&keywords=Arduino+Relay
), and it works perfectly with Uno-R3. I am mainly concerned about the 3.3V vs. 5V.. If you can share your (any) Relay Shield experience with Due, greatly appreciate it.