An ESP8266 Duck DNS client from Davide Gironi:
It is powered by USB, it can also be powered by the router USB port.
It’s built on a pretty old ESP-01 board.
It has two led, one is the ESP-01 WiFi connection status embedded one, the other is connected to the GPIO2 port, and it’s used for the DNS update status.
Project info at Davide Gironi’s blog. Code is available on github.
Check out the video after the break.