Garmin Watch App

Source Code Repository

The (GarminSD) watch app is stored in its own github repository.

Build Instructions

The app is written in ‘MonkeyC’ which is quite like C++ but with less reliable type checking. You need the Garmin SDK which includes the compiler, libraries and emulators.

The repository README file includes build instructions - I recommend using the Visual Studio Code method rather than the command line.

The ‘develop’ branch includes a new ‘Dev Container’ which is a build environment which contains the Garmin SDK and watch simulators and should allow you to compile and test the app without much configuration - we would appreciate feedback on whether this is true or not so we can update the devcontainer or documentation to make it easier for future developers.

Code Structure

Source Code

The MonkeyC source files are in the source folder.

• GarminSDApp.mc is the app entry point. It does the following:
  • Defines the application lifecycle callbacks (initialize() onStart(), onStop() and getInitialView().
  • Starts a timer which calls the onTick() function every second.
  • Declares mState which recorts the operating state of the app (used in other components)
  • getInitialView() specifies that the GarminSDView should be used for the initial display for the app.
• GarminSDView.mc handles drawing the display and interacting with user key presses. It also starts GarminSDDataHandler which deals with receiving data from the sensors. - onTick() is called from the GarminSDApp onTick function - it decides whether to re-draw the screen or not - we re-draw the screen as little as possible to reduce battery consumption. - the SdDeligate class handles user interaction (menu selection, button presses etc.) - the GarminSDSettingsMenu and GarminSDSettingsMenuDeligate classes handle display and user interaction of the app settings menu.
• GarminSdDataHandler.mc
  • Creates an instance of GarminSDComms to handle communications between the watch and the phone.
  • Starts the accelerometer collecting data.
  • Starts the heart rate and O2 saturation sensors if they are selected in the watch app settings.
  • accel_callback() is called whenever accelrometer data is available. It adds the received data into a buffer and if the buffer is full, it sends the accelerometer data, heart rate and O2 saturation data to the phone using the GarminSdComms instance (mComms).
• GarminSdComms handles sending the collected data to the phone, receiving the response from the phone and responding to the received response (alerting the user to an alarm state etc.)

Resources

Text strings are stored in the resources folder. Alternative language translations are stored in resorces- folders.