Is it possible to get heart rate updates from a Androidwatch in my app?

Question

I have an Android app and I want to read the heart rate from any connected Android watch (Wear OS, Tizen, etc). Is this possible without developing a wearable app?

I tried registering a listener on the Sensor.TYPE_HEART_RATE but I don't see any of the 3 watches that I have show up (Ticwatch E, Ticband, Gear S2). I ensured I request the Manifest.permission.BODY_SENSORS permission.

sensorManager = getSystemService(Context.SENSOR_SERVICE) as SensorManager?

    heartRateSensor = sensorManager?.getDefaultSensor(Sensor.TYPE_HEART_RATE)

    val registered = sensorManager?.registerListener(this, heartRateSensor, SensorManager.SENSOR_DELAY_NORMAL)
    Log.i(TAG, if (registered!!) "Registered Listener" else "Failed to register listener")

Tc

Answer 1

I did some research using an Android Wear watch, Samsung Gear S2, random heart rate fitness tracker watch (Ticwatch) and a standalone bluetooth heart rate arm band.

Just to reiterate my goal was to read heart rate data from the watch's sensor through my phone app without making a watch app.

My findings were as follows:

1. The code sample I posted above was in my phone app and the SensorManager only works with sensors that are built into the device. For example, if the app was running on the phone I would only get sensors on the phone, if on the watch I would get the ones on the watch. This obviously didn't work as no heart rate sensors showed up unless the phone had one built it. The same code in a watch app worked and I was able to get the heart rate that way.
2. Using the Fitness API and Samsung Health API I was able to get updates on the phone app when the heart rate was read. Only problem with this solution was you can't set the frequency of heart rate readings. To save battery life it looks like most watches cap the interval at every 10 minutes when still or every few seconds during a workout. This also didn't work as I needed more frequency updates.
3. The bluetooth heart rate armband was the only was I was able to get the heart rate read at the frequency I wanted. This solution required pairing to the monitor but it was a simple connection and I did not need to develop any watch apps!

I hope this clarifies how the SensorManager only works for sensors on the device the app is running on.

Tc

I am Very appreciate for your investigation! I just want to my app support hr devices as much as possible. armband - is it some model? Fitness API is it GoogleFit API or something else? Samsung Health API - is sdk from developer.samsung.com/health/android? Is it possible to see your code from this research? BTW thank you. – Malformation

@Malformation I do not have the code from this anymore but what I learned is you would need to handle the different sources of where you could get HR devices. 1. Device HR sensors - you could use the SensorManager in this case to listen to heart rate updates 2. Bluetooth HR sensors - your app would need to pair with the device to get the HR reading directly 3. From Android/Samsung watches - you would have to make a watch app to listen to this data coming in on your own terms (frequency of updates), otherwise you can use the Fitness API (or Samsung, Fitbit API, etc) to listen for HR updates. – Tc

Thanks for replay. About your last case (samsung for exmpl) I add samsung health sdk to my app and what next? How could I use thier API for listening updates. From their docs I can only sync post measured data. Also from fitbit forum: "Only FitbitOS devices (Ionic/Versa*) support our Device SDK. All other devices support our Web APIs, but those don't provide real-time data." – Malformation

@Malformation So you would add the Samsung health sdk, and in your app you would be able to subscribe to readings that get posted. Ex when the watch decides to send a reading to the watch's health app (Fitness, Samsung Health, Fitbit). The same can be done for Google (maybe Fitbit?). The problem is that you are limited to the rate that the watch decides to send the reading to the app. I found from my testing it was around 1 reading per 10 minutes which wasn't enough. – Tc

May be this some workaround if you activate some training mode on watch. During training watch sends data more frequently.. perhaps Thanks for reply. I decide to start with Google Fitness API – Malformation

Answer 2

Based from these posts 1 and 2, make sure that your application has defined and granted the Body Sensors permission.

Verify that:

<uses-permission android:name="android.permission.BODY_SENSORS"/>

is present in your wear AndroidManifest.xml

Also, ensure that the permission has been granted by checking the Permissions settings on the watch: Settings -> Permissions -> Your app

You may check this GitHub link for example.

Unrivalled

Please see my posted answer. I wanted to read the watch heart rate sensor without developing a watch app and I realized that calling this from the phone app doesn't work and doesn't show watch sensors. – Tc