[pookieinc]

Really beautiful work, I'd love to see a technical write-up on how this was achieved and would definitely follow something like that.

I'm interested in joining this, however I don't have such a wrist device. Which tracker would be best for receiving the most accurate data? Is there a recommended tracker (Fitbit vs. Jawbone vs. etc.) that provides more data, so this app can track more things for the user?

[aprilzero]

iPhones for the past few years have actually been tracking steps and other data in the background & storing it in Healthkit. You won't be able to get heart rate, but a lot of our views can be powered with just software.

Our new healthkit app (gyrosco.pe/app, currently in beta) loads steps from the iPhone, and we also integrate with other apps like Moves which also run on the phone.

The idea is you can get started within just a few minutes and not need to buy anything. We can also backfill the last year of data so you don't start with an empty site. Then you can start to add hardware to get more data you care about, like a wifi scale or heart rate monitor.

There are many other apps that also write to healthkit, like sleep tracking apps Sleep++ / Sleep Cycle, which will then show up.