The SitePoint PHP blog has a tutorial they've posted from Christopher Pitt showing you how to hack your Fitbit into a pager for Twitter DMs. This essentially turns your Fitbit into a notification system for when someone on Twitter sends you a direct message. It's not overly useful (as you can't send a message) but it is an interesting integration.
I’ve been trying to wake up earlier in the morning. The trouble is that alarms wake everybody up, not just me. To get around this problem, I recently bought the cheapest Fitbit I could find, having learned that they have a neat silent alarm.
The truth is, if I had the cash I would rather have bought an Apple watch. When I got the Fitbit, my programmer brain immediately jumped to the question; “How can I hack this thing?” I ended up learning a bit about Fitbit, OAuth and the Twitter API. I also learned that sometimes it’s better just to get an Apple watch…
His application uses Lumen as the framework and makes connections to both the Twitter and Fitbit JSON APIs. He defines a few routes for the OAuth handling (with callbacks) and a simple view with the "Connect To" links. He shows the creation of applications on both the Twitter and Fitbit side and how to define their keys in your configuration. He sets up the Socialite providers for both connections and a bit of caching to prevent the need for a full pull. He then uses the Fitbit API to set "silent alarms" on your device that are timed to go off immediately when the app detects a new DM on the Twitter stream.