I -have- built something like this for the TV using NFC cards, which was a great first-electronics-project for myself. That said, the most frustrating part is not the actual hardware itself but getting whatever streamer you're using to play the content you want. For example, this project required the author to WireShark and reverse engineer how Chromecast managed things.

If you do go down this route, I found that Plex offered the best deep-linking functionality and would wrap all of your content with that... but it was still somewhat unreliable.