Garmin-Watchface: How to show Heartrate?

Question

In a watchface I created which ConnectIQ (4.30) I can show the clocktime, but when I try to show the heartrate I get the error

Details: Module 'Toybox.Sensor' not available to 'Watch Face'

Stack: - onStart() at /Users/…/source/_garmin_projectAPP.mc:13 0x10000095 Permission Required

In the manifest I added all available permissions, I also imported the Sensor with

using Toybox.Sensor

I am also not sure where exactly to enable the heartrate-sensor with e.g.

Sensor.setEnabledSensors([Sensor.SENSOR_HEARTRATE]);
Sensor.enableSensorEvents(method(:onSensor));

I tried in the initialize() and onStart(state) method, but still I get the error shown above.

Answer 1

CIQ apps of type "watch face" do not have access to sensors in that manner. Instead you need to use the methods available in the Activity and/or ActivityMonitor modules.

If the watch device is newer it will likely support calling this method, which returns an heart rate value that is updated every second:

Activity.getActivityInfo().currentHeartRate()

Otherwise, you can call this method and use the most recent value, which will be the heart rate within the last minute:

ActivityMonitor.getHeartRateHistory()

In both cases you will need to check for a null value, which will happen if the sensor is not available or the user is not wearing the watch.

Answer 2

That didn't work for me. I had to do this, using currentHeartRate as a property, not a function method.

    var heartRate = null;
    var activity = Activity.getActivityInfo();
    if (activity != null) {
        heartRate = activity.currentHeartRate;
    }

I was able to also test this in the simulator using Simulation->Activity Data. I have not tested it on my real watch yet to see if this also works just while wearing it, and not during an "activity" .