Support for Garmin Watches

[thmichel]

Hi,

I am swtiching from Android to Sailfish and I'm looking for a way to sync my Garmin watch with it. Would you consider adding support for those watches (or accept a pull request for such a feature if I can manage to make it work with my (very) limited coding skills)?

I see GadgetBridge supports them, maybe some of it's code could be re-used in Amazfish.

[jmlich]

Pull requests are welcome. I have one Garmin device for tests.

• first you need to create new device into https://github.com/piggz/harbour-amazfish/tree/master/daemon/src/devices
• it should be child class from AbstractDevice
• The you need to enable device in Device Factory https://github.com/piggz/harbour-amazfish/blob/master/daemon/src/devicefactory.cpp and in DeviceModel https://github.com/piggz/harbour-amazfish/blob/master/ui/qml/components/DeviceListModel.qml

You can mostly reuse Pebble code for that. Its in early phase of implementation and contain just few device specific bits
https://github.com/piggz/harbour-amazfish/blob/master/daemon/src/devices/pebbledevice.cpp

Then you would like to reimplement BLE services. I suggest starting here:
https://github.com/Freeyourgadget/Gadgetbridge/blob/a0948ee1cbc2a870f91d313f8e37df5f524465f7/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/garmin/communicator/v1/CommunicatorV1.java
or
https://github.com/Freeyourgadget/Gadgetbridge/blob/a0948ee1cbc2a870f91d313f8e37df5f524465f7/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/garmin/communicator/v2/CommunicatorV2.java

[thmichel]

Thanks, I'll have a look at it. Guess the BLE services part is the hard one.

[thmichel]

Started to look at the code and through the documentation of the Garmin Protocol on GadgetBridge's Website, seems the BLE services for Garmin are quite complex. Looks like none of the standard BLE servies can be used as Garmin encapsulates everything in their own protocol. Will definitely take some time to implement even basic support I guess.

[piggz]

I had a quick scan .. looks like its using a protobuf based protocol, the .proto files are in GB and egm the Notification one doesnt look too complicated. we have a protobuf library in the source already, so hopefully you can use that. GarminSupport.java implies there are only 3 BLE services services to implement. Maybe start with a small goal of getting a notification to work. It would be great to see this added.

[thmichel]

My first goal is getting the watched paired properly :-)
A simple pair isn't sufficient, the watch expects some messages after initial bluetooth pairing. Thanks for the hint with the proto files, I'll look into this. It's all quite new to me, so don't expect results too fast.

[thmichel]

Looks like Qt5 does not support QtProtofuf for automated class generation as Qt 6 does. Would have made life much easier...

[piggz]

We have a tiny protobuf library in the source code already for reading huami sport summary data. Its probably not as nice to use, but it does seem to work. My original goal was to find a small library we can include in the code, but im open to better alternatives if they exist.

[alistair23]

My first goal is getting the watched paired properly :-) A simple pair isn't sufficient, the watch expects some messages after initial bluetooth pairing. Thanks for the hint with the proto files, I'll look into this. It's all quite new to me, so don't expect results too fast.

They are pretty complex.

The initial pari does require a few extra steps, but it doesn't end up being too hard to get a basic pair.

watchd is a Linux service that supports a lot of the Garmin communication. It's written in Rust. It doesn't support the data sync parts, but works with pretty much all of the other smart features. It's based on the GadgetBrige reverse engineering work, just translated to run on Linux with Rust instead of Android. That might be some help as well for protocol decoding and implementation.

[thmichel]

Thanks for that, I'll look at it. I am doing this in my free time, so don't expect it to go too fast.

[thmichel]

With the help of the Rust code, I now successfully completed the pairing process for my Epix Pro to Amazfish!

I admittedly used AI to translate the Rust code to C++ as I'm not familiar with Rust, so the code is overly complex, ugly and most likely buggy - took quite a while to do a basic cleanup and corrections, but at least I made some progress. Next steps will be cleaning up the code and trying to send notifications to the watch.

A long way to go, but it's a start.

[thmichel]

I went for the easier things first an worked on getting steps, heart rate and Spo2 from the watch, which generally works. I can see the heart rate in the Amazfish tile on the home screen, what I don't see is the heart rate in the application itself when it's open. It looks like the information isn't being put into the database by the daemon.
Currently all I do is emitting the informationChanged signal from the Garmin service, not sure what other steps need to be taken. @piggz , @jmlich : Any tips on what could be the problem?

Once I've worked this out, I can get to battery status and notifications. They both use protobuf so more complex than getting the simple values like heart rate.

[jmlich]

The steps/HR information is handled on two different levels.

Current information/status updates
This is the live information shown in the UI, for example:
emit informationChanged(Amazfish::Info::INFO_STEPS, QString::number(m_steps));

This data is not stored in the database; it is only passed directly to the UI.

Activity data synchronization
Historical activity data (steps, HR graphs, sleep, etc.) is handled separately through the activity sync mechanism.

Example of the flow:

• downloadActivityData() is triggered from the UI or from the Timer. It sends a request to the smartwatch to download activity data for a certain time period:
  

  harbour-amazfish/daemon/src/devices/banglejsdevice.cpp

  Lines 356 to 376 in 8139c63

  	void BangleJSDevice::downloadActivityData() {
  	qDebug() << Q_FUNC_INFO;
  	if (m_operationRunning) {
  	qDebug() << "Operation is running";
  	return;
  	}
  	UARTService *uart = qobject_cast<UARTService*>(service(UARTService::UUID_SERVICE_UART));
  	if (!uart) {
  	return;
  	}
  	qlonglong ls = AmazfishConfig::instance()->value("device/lastactivitysyncmillis").toLongLong();
  	m_samples.clear();
  	emit message(tr("Downloading activity data"));
  	setOperationRunning(true);
  	QJsonObject o;
  	o.insert("t", "actfetch");
  	o.insert("ts", ls);
  	uart->txJson(o);
  	}

• The smartwatch responds with packets containing activity data ("act" packets in the Bangle.js implementation):
  

  harbour-amazfish/daemon/src/devices/banglejsdevice.cpp

  Line 617 in 8139c63

  } else if (t == "act") {

• These packets are stored in a QList<>:
  

  harbour-amazfish/daemon/src/devices/banglejsdevice.cpp

  Line 638 in 8139c63

  ActivitySample sample = ActivitySample(actDate, ActivityKind::toHuamiRawType(kind), 100*mov/2048, steps, m_heartrate);

• After all data has been transferred, the smartwatch sends an "actfetch" packet with fetch_state:"end" to indicate completion:
  

  harbour-amazfish/daemon/src/devices/banglejsdevice.cpp

  Line 609 in 8139c63

  if (saveActivitySamples()) {

• Finally, saveActivitySamples() stores the data into SQLite:
  

  harbour-amazfish/daemon/src/devices/banglejsdevice.cpp

  Lines 768 to 807 in 8139c63

  	bool BangleJSDevice::saveActivitySamples() {
  	uint user_id = qHash(AmazfishConfig::instance()->profileName());
  	uint device_id = qHash(AmazfishConfig::instance()->pairedAddress());
  	KDbTransaction transaction = m_conn->beginTransaction();
  	KDbTransactionGuard tg(transaction);
  	KDbFieldList fields;
  	auto mibandActivity = m_conn->tableSchema("mi_band_activity");
  	fields.addField(mibandActivity->field("timestamp"));
  	fields.addField(mibandActivity->field("timestamp_dt"));
  	fields.addField(mibandActivity->field("device_id"));
  	fields.addField(mibandActivity->field("user_id"));
  	fields.addField(mibandActivity->field("raw_intensity"));
  	fields.addField(mibandActivity->field("steps"));
  	fields.addField(mibandActivity->field("raw_kind"));
  	fields.addField(mibandActivity->field("heartrate"));
  	for (int i = 0; i < m_samples.count(); ++i) {
  	QList<QVariant> values;
  	values << m_samples[i].datetime().toMSecsSinceEpoch() / 1000;
  	values << m_samples[i].datetime();
  	values << device_id;
  	values << user_id;
  	values << m_samples[i].intensity();
  	values << m_samples[i].steps();
  	values << m_samples[i].kind();
  	values << m_samples[i].heartrate();
  	if (!m_conn->insertRecord(&fields, values)) {
  	qDebug() << Q_FUNC_INFO << "error inserting record";
  	return false;
  	}
  	}
  	tg.commit();
  	m_samples.clear();
  	return true;
  	}

So reaching the current status updates (1) is already a very good start, and I would personally be happy to merge that into Amazfish as useful progress (assuming the code looks reasonable).

There was also an older sampling mechanism in the PineTime implementation that tried to periodically store recent values directly into the database, but it was somewhat unreliable and produced sparse/ugly graphs:

harbour-amazfish/daemon/src/devices/pinetimejfdevice.cpp

Line 248 in 8139c63

void PinetimeJFDevice::sampledActivity(QDateTime dt, int kind, int intensity, int steps, int heartrate) {

For Garmin, I think implementing proper activity synchronization will probably give much better results than trying to persist live values directly.

[thmichel]

Thanks, that's very helpfull. I will do some code cleanup now as I don't think it's in a state it should be merged yet quility wise. Once done, I'll create a pull request so you can go through it.

Regarding the database storage I need to check how this approach will work with Garmin, currently I only have the realtime services working. So that's something to look at once you are happy with merging the current code.

[thmichel]

I did a lot of code cleanup now, still might be some unnecessary stuff in it. What works so far:

• Initial pairing of the watch
• Realtime heart rate shown in GUI
• Realtime steps shown in GUI

Currently I match on "Epix" when scanning, not sure what other Garmin watches send, probably something like "Forerunner" or "Fenix" etc. I also use a wrong Icon as I didn't create one for Garmin yet.
So not sure if I should create a pull request just yet - maybe you want to have a look at the code first? It's here: https://github.com/thmichel/harbour-amazfish/ - I've created subfolders "garmin" under "devices" and "services".
I'd be greatfull for your guidance on what needs to be done before creating a pull request.
Once these basic features are working reliably, I can focus on getting battery stats and pulling the activity data from the watch to fill the database. That should then give me enough understanding of the protobuf stuff to get the notification sending done.