BackgroundServiceDelegate.mc

using Toybox.Background;
using Toybox.System as Sys;
using Toybox.Sensor;
using Toybox.ActivityRecording;

// The Service Delegate is the main entry point for background processes
// our onTemporalEvent() method will get run each time our periodic event
// is triggered by the system. This indicates a set timer has expired, and
// we should attempt to notify the user.
(:background)
class BackgroundServiceDelegate extends Sys.ServiceDelegate {



    function initialize() {
        ServiceDelegate.initialize();
    }

    function onTemporalEvent() {
        // Register callback for the accelerometer
        //var maxSampleRate = Sensor.getMaxSampleRate();
        var options = { :period => 1,
                        :sampleRate => 20,
                        :enableAccelerometer => true
        };
        Sensor.registerSensorDataListener(method(:accelCallback), options);
    }

    function accelCallback(sensorData) {
        // Reading from the accelerometr occured (after 20x calls, data are saved in the array for each X, Y, Z)
        if (sensorData.accelerometerData != null) {
            Background.exit(sensorData.accelerometerData.y);
        } else {
            Background.exit(null);
        }
    }

}