WHOOP does not have the presence in the wearable space as other brands, but in certain circles, it’s a household name. Their business model requires you to have a yearly app subscription to use their fitness tracker, but here at Hackaday, we are big fans of actually owning the devices you buy — which is why we were happy to hear about an open source and subscription free WHOOP compatible app!
The goal of the so-called OpenStrap project is not to re-create the WHOOP app. Rather, the algorithms and processing methods are developed from scratch, based on public research. It’s all calculated locally on a 1 Hz interval, based on the data the WHOOP 4.0 device feeds the app. As such, the health data collected from the watch, never leaves the phone. While not the main goal of the project, the privacy improvement of the app’s serverless nature cannot be overstated. However, to display metrics, you first need to get data off the WHOOP to begin with.
The crux of the issue with making the WHOOP 4.0 work without the official app is the reliance on proprietary Bluetooth protocols. Fortunately, the protocol itself ended up being relatively simple. The WHOOP 4.0 amounts to little more than a series of sensors that sit on the user’s wrist. As such, the app can subscribe to the Bluetooth feed and decode the data, right? Well, the devil is always in the details with such things, and the protocol came with its fair share of quirks. The hardware clock needs to be synchronized, or it simply defaults to zero Unix time. Moreover, the analog sensors like, ambient temperature are given in relative ADC values, and are not terribly useful without calibration. Regardless, the result of the reverse engineering effort speaks for itself with the OpenStrap app able to recreate much of the functionality in WHOOP’s official app.
Quite often, devices reliant on proprietary apps are little more than manufactured e-waste. While we don’t expect many of you to actually own a WHOOP 4.0, we do hope to see the OpenStrap project keep at least a few out of the landfill in the future.
Great hack :-)
It’s good to see this sort of thing. Essentially future proofing for the inevitable point at which devices are superseded and stop being supported.
No doubt projects like this will keep a few things from becoming ewaste in the future. At the very least it should put a halt to a little corporate greed.
Although I do wonder about the ensuing arms race. People jailbreaking their ipods comes to mind. I can’t imagine these corporations using that customer freedom as inspiration for improvements they’ll just see the loss in potential revenue.
It would be great if companies were forced to open source everything when they discontinued a web service or update support.
Elections matter
So true…
The current US administrations has made a start with the “Freedom to Fix” memorandum directing the EPA to clarify what repairs vehicle owners can legally perform on emissions systems without violating the Clean Air Act. The directive urges the EPA to deprioritize civil enforcement against individuals who attempt in good faith to fix their cars.
Would never happen under previous administrations. It’s the right path, just need to keep up the good work and keep electing the “right” candidates
Wish this has been rolled into the existing GadgetBridge project, but maybe someone will do that at some point. I was just looking for a way to do this.
Thanks for pointing this project out, was just about to say i wish for a project to do this for Garmins.
Yet the current version of the Whoop is the 5.0. And subscribers automatically get the new version when they return the old version. Upgrade is included in the expensive subscription. Therefore getting a whoop 4.0 is a tricky business to start with. And you can only connect under certain circumstances. Clearly the author of this article did not properly read up on the subject.
I wish it were not so, but whoop is an ewaste builder with its schemes.
It’s nice to be right, but the right thing is to be nice.
Let’s see how long it takes for a firmware update that encrypts the data to be pushed out.
Actually Whoop just mails you the 5.0 and asks you to give the 4.0 to someone who can get a free trial subscription. So there are likely 4.0s floating around (including mine, which now that I see this project may try and then may ditch the questionably worth-it subscription…)
Gadgetbridge could use some love
Personally I couldn’t use it because it doesn’t have feature parity with the proprietary apps, and for another (more shameful reason), I found the proprietary app UI much easier to use
Don’t you have to rent a whoop and pay for the app to get the hardware so you arnt saving money in reality?
Nice. I’d love to have something for my old BodyMedia BodyBugg that’s a bit easier to set up than FreeTheBugg, etc.