UNO Ethernet remote control

Use UNO R3 with W5100, a button on D2 to ground, LED output D5 with a series resistor, and a suitable relay module on D6. LED and relay outputs change together. Check the relay module's voltage and active level before connecting a load.

Install Remocon, Boho, Crypto, and Bounce2. Open uno-ethernet-button. Configure a unique Ethernet MAC and DHCP network. This example connects to io.remocon.kr:55488, uses an 80-byte receive buffer, and advertises the name UnoR3-EthBtn:HOME with on,off,toggle controls.

On ready, the device publishes @$state, @$ui, and @$name, announces its CID on #notify, and subscribes to #search. A #search request prompts another CID announcement. The @ui request supports an explicit reply to the requesting client. Direct @ text commands on, off, and toggle update outputs and publish the resulting state.

Connect a controller to the matching server, search for devices, select the announced CID, then send one command. Confirm both the physical output and the received state. The button also sends playToggle on #screen for the optional YouTube integration; a browser player requires an initial manual play gesture.

For a smaller board-free exercise, use the workbench's virtual device.