The goal for this project was to get some barebones performance metrics and watch but WITHOUT having to use a companion iOS/Android app.
Obviously your phone must be in the boat for this app to function as the code actually runs on the phone and the pebble is more or less a display.
Press the "select" button to start a countdown.
During countdown, press "up" or "down" to jump up or down to the next closest minute. eg: 3:15 + "down" = 3:00. 2:47 + "up" = 3:00.
The app will give a short vibrate on each minute (5/4/3/2/1) and a short vibrate each second for the last 10 seconds, and a long vibrate on start.
The middle number is speed in knots.
The bottom number is heading in degrees.
During each mark rounding, press "up" or "down" to log that mark. Once the app has at least 2 marks (start counts as a mark) it will calculate VMC to the previous mark. eg: if you round the leeward mark and hit "up"/"down" it will begin calculating VMG to the windward mark. Obviously if you are sailing to a different mark, or if a mark is moved, then the VMC number will be innaccurate. VMC is in knots.
Press "select" to clear all marks and restart the countdown.
The app will "remember" the start countdown and marks even if you leave the app and come back in.