MQTT Ethernet Node with 4 buttons and 4 leds (or relays).
Platform: Arduino-Uno with W5100-Ethernet-Shield.
Leds can be replaced with relays to create 4 relay node.
Button1 controls led1 and outgoing MQTT message1
Button2 controls led2 and outgoing MQTT meesage2
Button3 controls led3 and outgoing MQTT message3
Button4 controls led4 and outgoing MWTT message4
Incoming MQTT message1 controls led1
Incoming MQTT message2 controls led2
Incoming MQTT message3 controls led3
Incoming MQTT message4 controls led4
Note: Needs library Bounce2. This library is not yet available from Codebender website, but is to be downloaded from Arduino website.