Measure Types & Data

All measure types in this package live in the namespace dk.carp.watch.aware and are event-based: once started, they keep producing data until the study stops them.

Measure(type: AppleWatchSamplingPackage.MOTION)
// equivalent to
Measure(type: 'dk.carp.watch.aware.motion')

Constant	Type string	Data class
`AppleWatchSamplingPackage.MOTION`	`dk.carp.watch.aware.motion`	`AppleWatchMotion`
`AppleWatchSamplingPackage.HEART_RATE`	`dk.carp.watch.aware.heartrate`	`AppleWatchHeartRate`
`AppleWatchSamplingPackage.BATTERY`	`dk.carp.watch.aware.battery`	`AppleWatchBattery`
`AppleWatchSamplingPackage.LOCATION`	`dk.carp.watch.aware.location`	`AppleWatchLocation`
`AppleWatchSamplingPackage.HEADING`	`dk.carp.watch.aware.heading`	`AppleWatchHeading`
`AppleWatchSamplingPackage.BLUETOOTH`	`dk.carp.watch.aware.bluetooth`	`AppleWatchBluetooth`
`AppleWatchSamplingPackage.AMBIENT_NOISE`	`dk.carp.watch.aware.ambientnoise`	`AppleWatchAmbientNoise`
`AppleWatchSamplingPackage.AUDIO_LABEL`	`dk.carp.watch.aware.audiolabel`	`AppleWatchAudioLabel`
`AppleWatchSamplingPackage.DEVICE`	`dk.carp.watch.aware.device`	`AppleWatchDeviceInfo`

Fields

All nine data classes extend AppleWatchData:

Field	Type	Meaning
`deviceId`	`String?`	The AWARE device id of the watch that collected the record
`timestamp`	`DateTime`	When the watch recorded it (UTC) — not when the phone received it
`label`	`String?`	The AWARE data label from `AppleWatchDevice.label`, if set
`recordId`	`String?`	Stable identity of the record, used to discard duplicates

recordId is formed as watch device id / measure type / row id in the watch database. It is what makes re-transferred records safe: the same record never lands twice in the local CAMS database.

Reading the data

client.measurements
    .where((m) => m.dataType.toString() == AppleWatchSamplingPackage.HEART_RATE)
    .listen((measurement) {
      final heartRate = measurement.data as AppleWatchHeartRate;
      print('${heartRate.timestamp}: ${heartRate.hr} BPM');
    });

Motion

AppleWatchMotion: sampled at motionSamplingRate Hz. Fields belonging to a disabled sub-sensor (accelerometerEnabled, deviceMotionEnabled) are zero.

Field	Unit	Description
`accX`, `accY`, `accZ`	G	Raw acceleration, including gravity
`roll`, `pitch`, `yaw`	radians	Attitude
`gravityX`, `gravityY`, `gravityZ`	G	Gravity vector
`rotationX`, `rotationY`, `rotationZ`	rad/s	Rotation rate
`userAccX`, `userAccY`, `userAccZ`	G	User acceleration, gravity removed

Heart Rate

AppleWatchHeartRate: read from HealthKit on the watch.

Field	Unit	Description
`hr`	BPM	Heart rate in beats per minute

Requires the HealthKit capability and the participant’s permission, granted on the watch. Sampling frequency is decided by watchOS, not by this package and the watch measures more often during activity and less often at rest.

Battery

AppleWatchBattery: the battery of the watch itself.

Field	Unit	Description
`batteryLevel`	percent (0–100)	`-1` when unknown
`batteryState`	`WatchBatteryState`	`unknown`, `unplugged`, `charging`, or `full`

Location

AppleWatchLocation

Field	Unit	Description
`latitude`, `longitude`	decimal degrees	Position
`altitude`	metres	Above mean sea level
`ellipsoidalAltitude`	metres	Above the WGS 84 reference ellipsoid
`horizontalAccuracy`	metres	Radius of uncertainty
`verticalAccuracy`	metres	Vertical uncertainty
`speed`	m/s	Instantaneous speed
`speedAccuracy`	m/s	Accuracy of `speed`
`course`	degrees	Direction of travel relative to true north
`courseAccuracy`	degrees	Accuracy of `course`

If the phone is also collecting location through carp_context_package, make sure to disable one otherwise this results in two location streams.

Heading

AppleWatchHeading: compass and magnetometer.

Field	Unit	Description
`trueHeading`	degrees	Relative to true north
`magneticHeading`	degrees	Relative to magnetic north
`headingAccuracy`	degrees	Maximum deviation of the reported heading
`x`, `y`, `z`	microteslas	Geomagnetic field

Bluetooth

AppleWatchBluetooth: one record per device seen in a scan.

Field	Unit	Description
`identifier`	—	Identifier of the scanned device
`name`	—	Advertised name, if any
`rssi`	dBm	Received signal strength

Ambient Noise

AppleWatchAmbientNoise: sound pressure level. No audio is stored.

Field	Unit	Description
`decibel`	dB	Sound pressure level

Requires audioEnabled: true together with ambientNoiseEnabled: true.

Audio Label

AppleWatchAudioLabel: sound classification using Apple’s SoundAnalysis. No audio is stored.

Field	Unit	Description
`audioLabel`	—	The classified sound, e.g. `speech` or `laughter`
`confidence`	0.0–1.0	Confidence of the classification

Requires audioEnabled: true together with audioClassificationEnabled: true. Filter on confidence in analysis — low-confidence labels are frequent in noisy environments.

Device Information

AppleWatchDeviceInfo: collected once each time data collection starts on the watch.

Field	Description
`pairedIosDeviceId`	The AWARE device id of the phone this watch is paired with
`name`	The name of the watch, as set by the participant
`model`	Watch model, e.g. `Apple Watch`
`systemName`	Operating system name, e.g. `Watch OS`
`systemVersion`	Operating system version, e.g. `11.2`
`preferredContentSizeCategory`	The participant’s dynamic type setting

This is the record that links the watch’s AWARE device id to the phone’s.