Alexa + SmartThings + IFTTT + Harmony to turn TV on and off by voice (2015 version)

You don’t need to Use IFTTT anymore, at the time this was written the Harmony/smartthings integration was still in beta. You’re going to use the “harmony triggers” smart app instead of an IFTTT recipe. Everything else is the same. The point is that a virtual switch is treated exactly the same way as a regular switch once it has been created. So echo will just think it’s a regular SmartThings switch.

Here’s the harmony triggers FAQ.