BangleApps/apps/speedalt2

GPS Speed, Altimeter and Distance to Waypoint

What is the difference between GPS Adventure Sports and GPS Adventure Sports II ?

GPS Adventure Sports has 3 screens, each of which display different sets of information.

GPS Adventure Sports II has 5 screens, each of which displays just one of Speed, Altitude, Distance to waypoint, Position or Time.

In all other respect they perform the same functions.

The waypoints list is the same as that used with the GPS Navigation app so the same set of waypoints can be used across both apps. Refer to that app for waypoint file information.

Buttons and Controls

BTN1 ( Speed and Altitude ) Short press < 2 secs toggles the display between last reading and maximum recorded. Long press > 2 secs resets the recorded maximum values.

BTN1 ( Distance ) Select next waypoint. Last fix distance from selected waypoint is displayed.

BTN2 : Disables/Restores power saving timeout. Locks the screen on and GPS in SuperE mode to enable reading for longer periods but uses maximum battery drain. Red LED (dot) at top of screen when screen is locked on. Press again to restore power saving timeouts.

BTN3 : Cycles the screens between Speed, Altitude, Distance to waypoint, Position and Time

BTN3 : Long press exit and return to watch.

Touch Screen If the 'Touch' setting is ON then :

Swipe Left/Right cycles between the five screens.

Touch functions as BTN1 short press.

App Settings

Select the desired display units. Speed can be as per the default locale, kph, knots, mph or m/s. Distance can be km, miles or nautical miles. Altitude can be feet or metres. Select one of three colour schemes. Default (three colours), high contrast (all white on black) or night ( all red on black ).

Kalman Filter

This filter smooths the altitude and the speed values and reduces these values 'jumping around' from one GPS fix to the next. The down side of this is that if these values change rapidly ( eg. a quick change in altitude ) then it can take a few GPS fixes for the values to move to the new values. Disabling the Kalman filter in the settings will cause the raw values to be displayed from each GPS fix as they are found.

Loss of fix

When the GPS obtains a fix the number of satellites is displayed as 'Sats:nn'. When unable to obtain a fix then the last known fix is used and the age of that fix in seconds is displayed as 'Age:nn'. Seeing 'Sats' or 'Age' indicates whether the GPS has a current fix or not.

Power Saving

The The GPS Adv Sport app obeys the watch screen off timeouts as a power saving measure. Restore the screen as per any of the colck/watch apps. Use BTN2 to lock the screen on but doing this will use more battery.

This app will work quite happily on its own but will use the GPS Setup App if it is installed. You may choose to use the GPS Setup App to gain significantly longer battery life while the GPS is on. Please read the Low Power GPS Setup App Readme to understand what this does.

When using the GPS Setup App this app switches the GPS to SuperE (default) mode while the display is lit and showing fix information. This ensures that that fixes are updated every second or so. 10 seconds after the display is blanked by the watch this app will switch the GPS to PSMOO mode and will only attempt to get a fix every two minutes. This improves power saving while the display is off and the delay gives an opportunity to restore the display before the GPS power mode is switched.

The MAX values continue to be collected with the display off so may appear a little odd after the intermittent fixes of the low power mode.

Waypoints

Waypoints are used in [D]istance mode. Create a file waypoints.json and write to storage on the Bangle.js using the IDE. The first 6 characters of the name are displayed in Speed+[D]istance mode.

The GPS Navigation app in the App Loader has a really nice waypoints file editor. (Must be connected to your Bangle.JS and then click on the Download icon.)

Sample waypoints.json (My sailing waypoints)

[
  {
  "name":"NONE"
  },
  {
  "name":"Omori",
  "lat":-38.9058670,
  "lon":175.7613350
  },
  {
  "name":"DeltaW",
  "lat":-38.9438550,
  "lon":175.7676930
  },
  {
  "name":"DeltaE",
  "lat":-38.9395240,
  "lon":175.7814420
  },
  {
  "name":"BtClub",
  "lat":-38.9446020,
  "lon":175.8475720
  },
  {
  "name":"Hapua",
  "lat":-38.8177750,
  "lon":175.8088720
  },
  {
  "name":"Nook",
  "lat":-38.7848090,
  "lon":175.7839440
  },
  {
  "name":"ChryBy",
  "lat":-38.7975050,
  "lon":175.7551960
  },
  {
  "name":"Waiha",
  "lat":-38.7219630,
  "lon":175.7481520
  },
  {
  "name":"KwaKwa",
  "lat":-38.6632310,
  "lon":175.8670320
  },
  {
  "name":"Hatepe",
  "lat":-38.8547420,
  "lon":176.0089124
  },
  {
  "name":"Kinloc",
  "lat":-38.6614442,
  "lon":175.9161607
  }
]

Comments and Feedback

Developed for my use in sailing, cycling and motorcycling. If you find this software useful or have feedback drop me a line mike[at]kereru.com. Enjoy!

Thanks

Many thanks to Gordon Williams. Awesome job.

Special thanks also to @jeffmer, for the GPS Navigation app and @hughbarney for the Low power GPS code development and Wouter Bulten for the Kalman filter code.