A Hacker’s Introduction To DIY Light Guide Plates

Last year, I found myself compelled to make a scaled-down replica of the iconic test chamber signs from the video game Portal. If you’ve played the game, you’ll remember these signs as the illuminated monoliths that postmarked the start of every test chamber. In hyperstylized video game fashion, they were also extremely thin.

Stay tuned for cake at the end of this article.

True to the original, my replica would need to be both slimmed down and backlit with a uniform, natural white glow. As fate would have it, the crux of this project was finding a way to do just that: to diffuse light coming in from the edges so that it would emit evenly from the front.

What I thought would be quick project ended up being a dive down the rabbit hole that yielded some satisfying results. Today, I’d like to share my findings and introduce you to light guide plates, one of the key building blocks inside of much of today’s backlit screen technology. I’ll dig into the some of the working principles, introduce you to my homebrew approach, and leave you with some inspirational source code to go forth and build your own. Continue reading “A Hacker’s Introduction To DIY Light Guide Plates”

Breaking Into The Nintendo DSi Through The (Browser) Window

The Nintendo DSi was surpassed by newer and better handhelds many years ago, but that doesn’t stop people like [Nathan Farlow] from attempting to break into the old abandoned house through a rather unexpected place: the (browser) window.

When the Nintendo DSi was released in 2008, one of its notable features was a built-in version of the Opera 9.50 web browser. [Nathan] reasoned an exploit in this browser would be an ideal entry point, as there’s no OS or kernel to get past — once you get execution, you control the system. To put this plan into action, he put together two great ideas. First he used the WebKit layout tests to get the browser into weird edge cases, and then tracked down an Windows build of Opera 9.50 that he could run on his system under WINE. This allowed him to identify the use-after-free bugs that he was looking for.

Now that he had an address to jump to, he just had to get his code into the right spot. For this he employed what’s known as a NOP sled; basically a long list of commands that do nothing, which if jumped into, will slide into his exploit code. In modern browsers a good way to allocate a chunk of memory and fill it would be a Float32Array, but since this is a 2008 browser, a smattering of RGBA canvases will do.

The actual payload is designed to execute a boot.nds file from the SD card, such as a homebrew launcher. If you want to give it a shot on your own DSi, all you need to do is point the system’s browser to stylehax.net.

If you’re looking for a more exotic way to crack into a DSi, perhaps this EM glitching attack might tickle your fancy?

Continue reading “Breaking Into The Nintendo DSi Through The (Browser) Window”

AI And Savvy Marketing Create Dubious Moon Photos

Taking a high-resolution photo of the moon is a surprisingly difficult task. Not only is a long enough lens required, but the camera typically needs to be mounted on a tracking system of some kind, as the moon moves too fast for the long exposure times needed. That’s why plenty were skeptical of Samsung’s claims that their latest smart phone cameras could actually photograph this celestial body with any degree of detail. It turns out that this skepticism might be warranted.

Samsung’s marketing department is claiming that this phone is using artificial intelligence to improve photos, which should quickly raise a red flag for anyone technically minded. [ibreakphotos] wanted to put this to the test rather than speculate, so a high-resolution image of the moon was modified in such a way that most of the fine detail of the image was lost. Displaying this image on a monitor, standing across the room, and using the smartphone in question reveals details in the image that can’t possibly be there.

The image that accompanies this post shows the two images side-by-side for those skeptical of these claims, but from what we can tell it looks like this is essentially an AI system copy-pasting the moon into images it thinks are of the moon itself. The AI also seems to need something more moon-like than a ping pong ball to trigger the detail overlay too, as other tests appear to debunk a more simplified overlay theory. It seems like using this system, though, is doing about the same thing that this AI camera does to take pictures of various common objects.