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Comment by theli0nheart | Hacker News Reader

Pretty much any Garmin device does exactly what you're looking for. All of the activity data on my fēnix 5 / VA HR is visible when I plug in via USB. The data is encoded in the FIT file format, which has a public SDK [1] (you do need to accept a license agreement to view it, though, if that matters). There are wrappers for most languages and if you want to just translate the data to CSV, there are pre-made tools to do that too.

I don't think you need to enable sync, so keeping the data local wouldn't be an issue. AFAIK, you should just be able to use the Garmin Connect software once to set up the watch, and that's it.

The great thing about the Garmin watches is that pretty much any fitness hardware that uses ANT+ will work with them. ANT+ is also an open protocol so you're not locked in with a specific manufacturer.

[1]: https://www.thisisant.com/resources/fit

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I am unwilling to accept an SDK's license in order to view my own data produced by my own hardware.

So, a couple years ago, I wrote a bash-wrapper [1] to Suto's perl FIT-parsing library [2]. With a quick search, I see that others may have extended Suto's work [3].

I'm pro-Garmin but can't understand hiding a measurement instrument's output format behind a closed-door license.

[1] https://github.com/4kbt/ParseVivosmartHR

[2] http://pub.ks-and-ks.ne.jp/cycling/GarminFIT.shtml

[3] https://github.com/mrihtar/Garmin-FIT

Isn't SDK licensing pretty normal, outside of open source?

> outside of open source

Yes? By definition, if it's not open source, then you're looking at a proprietary license of some sort.

What I meant is the outside-of-companies open source community.

It's not weird for a company to license their SDK, no matter what it's for. Par for the course rather.

That's not by definition at all- a work can be open source with a "proprietary license of some sort", or closed source, with source that's liberally licensed- but never published.

"Shared source"?

The trouble is that the FIT file specification, in addition to the parsing libraries, is behind the license.

It is possible to state the definition of a file format without opening any proprietary code.

I'll confirm the Garmin route as the way to go if you don't want to make a career out of getting the data off whatever Chinese bobble you found on AliExpress. You can get as fancy, or not, as you want. Plug into USB, drag-and-drop files somewhere and hackity hack. Or get all fancy and write wrapper code to prettify the data.

I don't think the watch ever needs to connect to anything in order to set it up, it can all be done on the watch (though Garmin Connect will make it easier). I do know that once it's set up, you can just turn the radio transmitters off and work through USB.

Seconded on Garmin, Tactix Bravo owner here. They’ve made a serious effort to support their developer community, and as such I’ve written a few apps and watchfaces for it. And as you say, there are many options for viewing and manipulating the data - IIRC, you can even download it from their servers after you’ve synced it, if you prefer.

I'm not sure if this is a question about Garmin or ANT+, but assuming a device is Bluetooth enabled, is there documentation for the Bluetooth API? I really want to find a nice smart fitness thing, but no one makes apps for my phone, so I figure I'd need to make one myself.

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