Making A Locked Down Wearable Work Without A Subscription

July 15, 2026 by Fenix Guthrie No comments

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.

Hacking Around The Financial Pain Of New 3DS XL Top Screens

July 15, 2026 by Maya Posch 1 Comment

With Nintendo’s 3DS experiencing a bit of a renaissance lately, prices for functioning systems have shot through the roof. Getting a busted one with a broken screen is a lot cheaper, but then you run into the eye-watering price difference between a replacement top screen for the regular version and the larger XL variant. The latter costs about the same as a whole new used 3DS, while the former goes for peanuts. Here the solution is obvious, with [Skawo] demonstrating how they hacked the cheaper, smaller top screen into a New 3DS XL.

The price difference on AliExpress as shown in the video is on the order of $120, with the smaller screen going for less than $10. Since they both use the same connector pin-out and display technology, you can plug either display into the New 3DS XL mainboard.

Where you’ll run into issues, other than the replacement display being obviously not XL, is the physically shorter flat flex cable for the controls that forces the display to be installed in an offset manner. You need jailbroken firmware like Luma3DS here to adjust for the screen offset. Filling in the missing screen real-estate is the other issue you have to patch over somehow, which was done here in barbaric fashion with some cardboard.

Beyond that it does work, and as a fix to at least get a broken New 3DS XL back into the game it’s worth considering. Do note that there’s a difference between regular 3DS and New 3DS (second generation) screens with neither being compatible, so be careful before you try such a fix.

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The OpenOscar Server in terminal, with Pidgin connected

AIM-ing For A More Open Platform Than Discord

July 14, 2026 by Tyler August 5 Comments

Do you remember AIM? It may suprize you to hear that AOL’s instant messanger was actually supported all the way up to 2017– two years after Discord launched. Unlike Discord, AIM is a protocol, not a platform. Everything on your favourite Discord server is at the mercy of the corporate masters of said server; you can’t just spool up your own. Not so for AIM, as [Veronica] explains, both on her blog and in a YouTube video that we’ve embedded below.

The key is the fact that the AIM protocol isn’t locked into AOL’s now-defunct servers; it was reverse engineered in its prime for open-source messengers like Pidgin. You can host your own server, too, using the OpenOscarServer by [mk6i]. Even better, it’s not just AIM, but ICQ! In the sort of irony you only get in real life, the OpenOscar community does all its support on a Discord server. But then, they couldn’t hardly do it over AIM or ICQ these days.

For those of you who were too old or too young to get sucked into the 90s instant messenger craze, these protocols don’t just create chat rooms, that would be the even older Internet Relay Chat protocol, but usually worked more like SMS text messages. You have a contact list, and you send messages to your contacts via a server that acts as a hub. Once upon a time, that server was AOL’s, but now thanks to the OpenOscar project, it can be anybody’s computer. Of course, like texting, you can rope all of your contacts into one big group chat, and the protocol does support images and VOIP. (Which is starting to sound a lot like Discord.)

If you’re tired of your friend-group being at the mercy of American tech companies, [Veronica]’s blog post serves as a good guide to get you started running OpenOscarServer on a Linux system; she used a virtual private server but figures a Raspberry Pi ought to have enough grunt if you don’t have a huge number of people signed up.

For completeness, we should mention that while AOL pulled the plug on AIM nearly a decade back, ICQ, the other protocol supported by OpenOscarServer, lasted straight through until 2024.

Thanks to Keith Olson for the tip! Our tipsline is based on decentralized “electronic mail” technology that anyone can access.

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Benchmarking Repairability Scores With An Asus Tablet

July 14, 2026 by Maya Posch 5 Comments

A few years ago, France introduced a mandatory repairability score for consumer goods like laptops and tablets. It involves five criteria that range from documentation and availability of spare parts to ease of disassembly, with the manufacturer using a government-provided checklist to determine their score.

Recently Asus determined that their Asus ROG Flow Z13 – model GZ302EA – scored a 10 out of 10 using this system. This led [iFixit] to run the same tablet/laptop hybrid through their own rating system.

You can find the filled-out spreadsheet for this device here, with this Asus-provided site showing a list of devices that all score a 10/10 or a measly 9.9/10 according to this system. As a self-reported score it is hard to take it as the objective truth, as there is every incentive for the manufacturer to tweak the truth to their own benefit and gloss over inconveniences. This is where it’s interesting to compare it with [iFixit]’s 7/10 score.

On documentation, Asus gives itself a perfect score but [iFixit] finds it to be incomplete. Removal of one fan requires the disassembly of the cooler with its liquid metal thermal interface on the CPU. The wireless card, and most ports, are soldered to the mainboard. On the bright side, after you get the screen off, the insides are quite modular, which is a plus.

[iFixit] dings three points: for documentation, soldered-down components, and a fan accessibility glitch. Parts accessibility outside of France is also significantly harder, but one can hardly blame the French system for that. Overall the French self-reported rating would seem to be a fair start, but depending on which criteria you define as required you may find yourself disagreeing with the score.

In the case of LPDDR5 RAM one could argue for example that with LPCAMM2 modules soldering RAM onto the mainboard ought to be a thing of the past, and Wi-Fi modules should always be removable as well. You can take that up with the French regulators.

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Full Body VR Tracking Is Just Some Recycled Hardware Away

July 14, 2026 by Donald Papp 3 Comments

Full body tracking in VR applications involves attaching sensors to one’s body, and [Jaki] has a DIY method to do it on the cheap: the Vive Tracker Lite project repurposes Vive controllers as lighthouse-based trackers, no hardware modifications required.

A common method of doing body tracking is to strap on some Vive trackers. Those are extremely hacker-friendly pieces of hardware, but [Jaki] observed that older Vive VR controllers can be had for cheap, and already contain everything a tracker needs. Some new firmware and a custom mount is all it takes to turn them into perfectly usable body trackers.

But what about a wireless receiver? [Jaki] has that covered as well with the $5 Viva Dongle, which uses a Pro Micro NRF52840 to act as a cheap DIY alternative to the official dongle hardware.

We appreciate the effort put into making this project accessible to everyone, even novices. [Jaki]’s put effort into a Python program with a full GUI to make the flashing of firmware as easy as possible for both projects. Experimenting with body tracking in VRChat or games with mods is just some recycled hardware away.

Granted, a Vive controller is not the slimmest piece of hardware, but all it takes is a firmware change and a 3D-printed fixture to make a perfectly serviceable tracker. That being said, we’re sure an enterprising hardware hacker may crack a controller open and embark on a serious rebuild, or even interface to some of the inputs in a clever way. If you’ve done that or know of someone who has, drop us a note on our tips line because we’d love to see it.

The Neo Geo Does Run DOOM After All

July 14, 2026 by Maya Posch 13 Comments

Demonstration of the DoomGeo port of Doom to the Neo Geo. (Credit: Sabino, GitHub)

Perhaps the most ridiculous statement that anyone can make is that a computer system with clearly enough processing power ‘cannot run DOOM‘. This is why we accept the premise that a PDP-11 cannot run this game, but something on the order of a Neo Geo gaming console with its 68000 processor and for the time impressive GPU definitely ought to be able to.

The stated problem here is a lack of RAM for a framebuffer, with the CPU only having 64 kB to play with. This limitation now has seen two different approaches to try and circumvent it, as covered by [Modern Vintage Gamer].

The first project here is Doom64kB, which as the name suggests tries to somehow work with this system RAM limitation. It uses the Doom8088 port for the original IBM PC and similar Intel 8088-based systems. This had to massively reduce the feature list, including the lack of texture mapping for floors and ceiling, no saving or loading, and no music.

The other project is DoomGeo, which doesn’t try to bend the Neo Geo hardware to its will, but accepts the Neo Geo way of doing things: involving sprite strips, pre-baked graphics, fix-layer UI, and a minimum of runtime data. This of course drastically changes how the Doom game engine normally works, with its framebuffer-based rendering.

From this we can thus conclude that it’s not so much the processing power that limits where DOOM can run, but more of how framebuffer-friendly the system architecture is, yet with some ingenuity and a complete rewrite of the game engine even that is no major obstacle.

(Top image: Neo Geo AES console. Credit: Evan-Amos, Wikimedia)

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2026 Frikkin Lasers Challenge: Laser Bandsaw

July 14, 2026 by Tyler August 20 Comments

Can you call it a bandsaw if it has neither band nor saw? [WeldingRod1] does, with his entry in the laser contest — a manually-controlled laser cutter that he’s dubbed a Laser Bandsaw. Some might quibble that it’s not actually sawing with the beam, and others will inevitably find the safety implications rather frightening. We think it’s a fun project and that [WeldingRod1] can call it what he wants, as long as he follows his own advice and keeps his laser goggles firmly on his precious vision orbs.

He has actually put some thought into what started as the physical manifestation of a joke in a podcast. The blue diode laser — a NUBM44 diode rated at 7 W — got a custom-made copper heatsink. It’s also got a hefty beam dump in the form of a stack of box knife blades. That’s very necessary to keep the beam from reflecting where it shouldn’t, especially when you consider this operates like a regular band saw: you turn it on, and it’s ready to cut. With only 7 W of laser power it can’t cut that much, mind you, but apparently it’s great on balsa wood and blasts black paint off like nobody’s business.

Now if this was our shop we’d probably want to put the laser diode onto some kind of CNC platform, be it Cartesian or SCARA. But we’ve seen that done many, many times and if you’ve got the motor skills this might be just the tool for you. There’s a pinout and STLs for the 3D printed frame on the project page if you’re interested. If not, why are you still here? The article is finished. Go make something lase and send it in. The deadline for the 2026 Frikkin Laser Contest is fast approaching!