Use Alexa to voice control a relay connected to the Internet via ESP8266.
I wanted to build a voice controlled smart outlet that was cheap and that didn’t require an existing smart home infrastructure (i.e. SmartThings or HomeKit). There are probably cheaper ways of doing this but I had an unused Power Tail and an ESP8266. This project can be adapted to drive any digital IO pin using Alexa and covers the integration of Alexa, IFTTT and Adafruit.IO.