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Ask HN: Is there a fitness wristband that is hackable?

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71–80 of 122 posts

Re: Ask HN: Is there a fitness wristband that is hackable?

#71

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 d…

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.

Re: Ask HN: Is there a fitness wristband that is hackable?

#72
post #70

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 d…

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/ParseVivosmar…

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

Re: Ask HN: Is there a fitness wristband that is hackable?

#73

If you have an iPhone, an Apple Watch meets your description perfectly. It has GPS, heart monitor, and pedometer data, and stores it in your local HealthKit database, which you can easily read and write with your own Swift code running on an iPhone. You can also write apps for the watch directly, and there is a non-LTE model.

And you can also export the data without writing Swift apps, if what I’m reading here is true:

https://github.com/kdesch5000/AppleHealthData

Save your effort for the analysis!

Re: Ask HN: Is there a fitness wristband that is hackable?

#74
post #70

Earlier quoted context omitted.

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/ParseVivosmar…

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.

Re: Ask HN: Is there a fitness wristband that is hackable?

#75
post #70

Earlier quoted context omitted.

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/ParseVivosmar…

Isn't SDK licensing pretty normal, outside of open 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.

Re: Ask HN: Is there a fitness wristband that is hackable?

#77

A few years back, I played around with TI's EZ430-Chronos: http://processors.wiki.ti.com/index.php/EZ430-Chronos?DCMP=C... It's not sleek like modern fitness bands/watches but is hackable. TI has more Smart Watch components and reference designs here: http://www.ti.com/solution/smart-watch

Chronos is cool, and definitely hacker-friendly, but it's not a proper fitness watch per se - it's just a demonstration TI made for their CC430 chips. Doesn't have much computational power or sensors onboard, but it features an 433/868/915 MHz radio (frequency depends on the model you pick) - and I mean actual, hackable radio - and it lasts forever on a coin cell.

I had lots of fun tinkering with it, but it's not really what the OP is looking for.

Re: Ask HN: Is there a fitness wristband that is hackable?

#78
post #25
post #19

Earlier quoted context omitted.

I looked at Pebble and I was surprised to see they were out of business.

Which, from your point of view, isn't a bad thing. It's no longer dependant on external servers, yet still enjoys a lot of support, is easy to code for, plus it's superb as smart watches go. Charging 3 times a month rather than every night means you can track your sleep with it effectively as well.

It is a bad thing, because electronics get old and eventually die. There isn't really any other company like Pebble on the market (Garmin is probably the only contender here), featuring quality hardware, e-Paper screens and a hacker-friendly ecosystem. So when your watch dies, you'll be forced to downgrade.

(I'm a happy owner of Pebble Time, and I dread the day it lets out the magic smoke.)

Re: Ask HN: Is there a fitness wristband that is hackable?

#79

On a related note, is there a wristband with a vibrating alarm clock that can set multiple alarm times and doesn't need a phone to trigger it? I'd like to pre-program the wristband to wake me up in case my phone (my main alarm clock) turns off for some reason.

You can do this with the $20 Xiaomi Mi Band 2. It's the MVP of a smartwatch in the best way possible.

Re: Ask HN: Is there a fitness wristband that is hackable?

#80
post #44

There are a number of Chinese generic activity trackers containing the Nordic nrf52832 MCU and a GPS module which are easily hacked and would meet all your needs. Search for "nrf52832 gps bracelet" or "nordic gps bracelet" on Aliexpress, Banggood, ebay etc. For example: https://www.aliexpress.com/item/KINCO-OLED-GPS-Activity-Trac... Components: Nordic nrf52832/ARM Cortex M4 MCU, Kionix KX023 accelerometer, Ublox GPS…

Do you know any blog posts or similiar where this is described in more detail?
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