Overview

carp_aware_package adds an Apple Watch as a data source to a CARP Mobile Sensing (CAMS) study. The watch collects motion, heart rate, location, sound and more while the participant wears it (including when the phone app is closed) and hands the data to the phone a few times an hour.

The flutter sampling package wraps the AWARE watchOS sensing framework by Yuuki Nishiyama (The University of Tokyo).

Caution

This package is iOS and watchOS only, and it needs a companion watchOS app inside your Flutter app’s Xcode project. Without it, the package has nothing to receive. Adding it is a one-time setup described in The Watch App.

What it collects

Nine measure types, within dk.carp.watch.aware namespace:

Measure type	Data class	What it holds
dk.carp.watch.aware.motion	AppleWatchMotion	Acceleration, attitude, gravity, rotation rate, user acceleration
dk.carp.watch.aware.heartrate	AppleWatchHeartRate	Heart rate in BPM, read from HealthKit
dk.carp.watch.aware.battery	AppleWatchBattery	Battery level and charging state of the watch
dk.carp.watch.aware.location	AppleWatchLocation	Latitude, longitude, altitude, speed, course
dk.carp.watch.aware.heading	AppleWatchHeading	Compass heading and geomagnetic field
dk.carp.watch.aware.bluetooth	AppleWatchBluetooth	Nearby Bluetooth devices seen by the watch
dk.carp.watch.aware.ambientnoise	AppleWatchAmbientNoise	Noise level in decibel
dk.carp.watch.aware.audiolabel	AppleWatchAudioLabel	Sound classification labels (speech, laughter, …)
dk.carp.watch.aware.device	AppleWatchDeviceInfo	Watch model, watchOS version, and the phone it is paired with

Every field of every type is documented in Measure Types & Data.

Note

No raw audio ever leaves the watch. Sound sensing produces a decibel number and a classification label where the recording itself is analysed on the watch and discarded.

How it works

Data transfer

The watch buffers locally and transfers every 15 minutes by default. Each record includes the timestamp given by the watch.

Background collection

The watch keeps collecting when it is out of range, and when the phone app has been killed. iOS wakes your app in the background to receive the files.

Protocol configuration

Sampling rates and which sensors run are part of the study protocol. Deploying a new protocol from CARP Web Services reconfigures the watch.

How It Works walks through the full path from a sensor reading on the watch to a row in your data set.

Requirements

iOS deployment target	16.0
watchOS deployment target	8.0
Flutter	3.29 or newer (Swift Package Manager support)
Dart SDK	3.8 or newer
Testing	A physical iPhone with a paired Apple Watch

Tip

The simulator cannot pair a watch to a phone in a way that makes WatchConnectivity file transfers work end to end, and heart rate needs real hardware thus requiring a real device.

Where to start

Install & ConfigureAdd the dependency and prepare the iOS project

QuickstartA complete study protocol with an Apple Watch in it

The Watch AppAdd the companion watchOS app — the required step

Configuring the WatchEvery setting on AppleWatchDevice, and what it costs

Credits

The watchOS sensing framework wrapped by this package is com.awareframework.ios.sensor.applewatch by Yuuki Nishiyama (The University of Tokyo), available under the Apache License 2.0.

If this framework supports your research, please cite:

Y. Nishiyama and K. Sezaki, “Smartwatch-Based Sensing Framework for Continuous Data Collection: Design and Implementation”, UbiComp/ISWC ’23 Adjunct, pages 620–625, ACM, 2023.