Sat Alert is a Pebble watchface that alerts the user to satellites traveling overhead. It currently tracks ~40 satellites. The app takes TLE data of satellite movements and generates latitude and longitude coordinates. It calculates the distance between the satellites and the user. If a satellite is above the user, the app alerts the user. If it is after dusk, the app tells the user the satellite may be visible as well as tells the user which direction to look to see the satellite.

This project is solving the Alert-Alert! challenge.


We used the Pebble Javascript SDK, satellite-js, SunCalc, and NORAD TLE satellite data to find where the most visible Space Objects are, and warn you when they are around you by the way of a WatchFace

Project Information

License: MIT license (MIT)

Source Code/Project URL:


Website -


  • Quentin Devauchelle
  • Harry Whelchel
  • Roman Zadov
  • Matt Higgins
  • Anne Willborn
  • Matthew Knudsen