DIY Laser Tag Project Does It In Style

October 26, 2024 by Donald Papp 21 Comments

This DIY lasertag project designed by [Nii], which he brought to Tokyo Maker Faire back in September, is a treasure trove. It’s all in Japanese and you’ll need to visit X (formerly Twitter) to see it, but the images do a fine job of getting the essentials across and your favorite translator tool will do a fair job of the rest.

There’s a whole lot to admire in this project. The swing-out transparent OLED display is super slick, the electronics are housed on a single PCB, the back half of the grip is in fact a portable USB power bank that slots directly in to provide power, and there’s a really smart use of a short RGB LED strip for effects.

The optical elements show some inspired design, as well. An infrared LED points forward, and with the help of a lens, focuses the beam tightly enough to make aiming meaningful. For detecting hits, the top of the pistol conceals a custom-made reflector that directs any IR downward into a receiver, making it omnidirectional in terms of hit sensing but only needing a single sensor.

Want to know more? Check out [Nii]’s earlier prototypes on his website. It’s clear this has been in the works for a while, so if you like seeing how a project develops, you’re in for a treat.

As for the choice of transparent OLED displays? They are certainly cool, and we remember how wild it looks to have several stacked together.

Donated Atari Mega ST Gives A Peek At Game Development History

October 25, 2024 by Donald Papp 9 Comments

[Neil] from The Cave, a computer and console gaming museum in the UK, has a treat for vintage computing and computer gaming enthusiasts. They received an important piece of game dev history from [Richard Costello], who coded ports of Gauntlet 2, Mortal Kombat, and Primal Rage for Atari ST and Amiga home computers. [Richard] brought them his non-functional Atari Mega ST in the hopes that they could get it working again, and demonstrate to visitors how game development was done back in the 80s — but sadly the hardware is not in the best shape.

The Atari ST flagged deleted files for overwriting but didn’t actively wipe them, allowing an undelete utility to work.

That doesn’t stop [Neil], however. The real goal is seeing if it’s possible to re-create the development environment and access the game assets on the SCSI hard drive, and it’s not necessary to revive every part of the hardware to do that. The solution is to back up the drive using a BlueSCSI board which can act as a host, scan the SCSI bus, and dump any device it finds to an SD card. The drive didn’t spin up originally, but some light percussive maintenance solved that.

With the files pulled off the drive, it was time to boot it up using an emulator (which begins at the 16:12 mark). There are multiple partitions, but not a lot of files. There was one more trick up [Neil]’s sleeve. Suspecting that deleting everything was the last thing [Richard] did before turning the machine off decades ago, he fired up a file recovery utility. The Atari ST “deleted” files by marking them to be overwritten by replacing the first letter of the filename with a ‘bomb’ character but otherwise leaving contents intact. Lo and behold, directories and files were available to be undeleted!

[Neil] found some fascinating stuff such as mixed game and concept assets as well as what appears to be a copy of Ramrod, a never-released game. It’s an ongoing process, but with any luck, the tools and environment a game developer used in the 80s will be made available for visitors to experience.

Of course, modern retro gaming enthusiasts don’t need to create games the classic way; tools like GB Studio make development much easier. And speaking of hidden cleverness in old games, did you know the original DOOM actually had multi-monitor support hidden under the hood?

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Behold A First-Person 3D Maze, Vintage Atari Style

October 20, 2024 by Donald Papp 15 Comments

[Joe Musashi] was inspired by discussions about 3D engines and decided to create a first-person 3D maze of his own. The really neat part? It could have been done on vintage Atari hardware. Well, mostly.

He does admit he had to do a little cheating to make this work; he relies on code for the ARM processor in the modern Atari VCS do the ray casting work, and the 6507 chip just handles the display kernel. Still, running his demo on a vintage Atari 2600 console could be possible, but would definitely require a Melody or Harmony cartridge, which are special reprogrammable cartridges popular for development and homebrew.

Ray casting is a conceptually simple method of generating a 3D view from given perspective, and here’s a tutorial that will tell you all you need to know about how it works, and how to implement your own.

[Joe]’s demo is just a navigable 3D maze rather than a game, but it’s pretty wild to see what could in theory have run on such an old platform, even if a few modern cheats are needed to pull it off. And if you agree that it’s neat, then hold onto your hats because a full 3D ray casting game — complete with a micro physics engine — was perfectly doable on the Commodore PET, which even had the additional limitation of a monochrome character-based display.

Make Your Own Remy The Rat This Halloween

October 19, 2024 by Donald Papp 10 Comments

[Christina Ernst] executed a fantastic idea just in time for Halloween: her very own Remy the rat (from the 2007 film Ratatouille). Just like in the film Remy perches on her head and appears to guide her movements by pulling on hair as though operating a marionette. It’s a great effect, and we love the hard headband used to anchor everything, which also offers a handy way to route the necessary wires.

Behind Remy are hidden two sub-micro servos, one for each arm. [Christina] simply ties locks of her hair to Remy’s hands, and lets the servos do the rest. Part of what makes the effect work so well is that Remy is eye-catching, and the relatively small movements of Remy’s hands are magnified and made more visible in the process of moving the locks of hair.

Originally Remy’s movements were random, but [Christina] added an MPU6050 accelerometer board to measure vertical movements of her own arm. She uses that sensor data to make Remy’s motions reflect her own. The MPU6050 is economical and easy to work with, readily available on breakout boards from countless overseas sellers, and we’ve seen it show up in all kinds of projects such as this tiny DIY drone and self-balancing cube.

Want to make your own Remy, or put your own spin on the idea? The 3D models and code are all on GitHub and if you want to see more of it in action, [Christina] posts videos of her work on TikTok and Instagram.

[via CBC]

All System Prompts For Anthropic’s Claude, Revealed

October 12, 2024 by Donald Papp 5 Comments

For as long as AI Large Language Models have been around (well, for as long as modern ones have been accessible online, anyway) people have tried to coax the models into revealing their system prompts. The system prompt is essentially the model’s fundamental directives on what it should do and how it should act. Such healthy curiosity is rarely welcomed, however, and creative efforts at making a model cough up its instructions is frequently met with a figurative glare and stern tapping of the Terms & Conditions sign.

Anthropic have bucked this trend by making system prompts public for the web and mobile interfaces of all three incarnations of Claude. The prompt for Claude Opus (their flagship model) is well over 1500 words long, with different sections specifically for handling text and images. The prompt does things like help ensure Claude communicates in a useful way, taking into account the current date and an awareness of its knowledge cut-off, or the date after which Claude has no knowledge of events. There’s some stylistic stuff in there as well, such as Claude being specifically told to avoid obsequious-sounding filler affirmations, like starting a response with any form of the word “Certainly.”

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Remembering John Wheeler: You’ve Definitely Heard Of His Work

October 12, 2024 by Donald Papp 9 Comments

Physicist John Archibald Wheeler made groundbreaking contributions to physics, and [Amanda Gefter] has a fantastic writeup about the man. He was undeniably brilliant, and if you haven’t heard of him, you have certainly heard of some of his students, not to mention his work.

Ever heard of wormholes? Black holes? How about the phrase “It from Bit”? Then you’ve heard of his work. All of those terms were coined by Wheeler; a knack for naming things being one of his talents. His students included Richard Feynman and Kip Thorne (if you enjoyed The Martian, you at least indirectly know of Kip Thorne) and more. He never won a Nobel prize, but his contributions were lifelong and varied.

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Memristors Are Cool, Radiation-resistant Memristors Even Moreso

October 5, 2024 by Donald Papp 9 Comments

Space is a challenging environment for semiconductors, but researchers have shown that a specific type of memristor (the hafnium oxide memristor, to be exact) actually reacts quite usefully when exposed to gamma radiation. In fact, it’s even able to leverage this behavior as a way to measure radiation exposure. In essence, it’s able to act as both memory and a sensor.

Being able to resist radiation exposure is highly desirable for space applications. Efficient ways to measure radiation exposure are just as valuable. The hafnium oxide memristor looks like it might be able to do both, but before going into how that works, let’s take a moment for a memristor refresher.

A memristor is essentially two conductive plates between which bridges can be made by applying a voltage to “write” to the device, by which one sets it to a particular resistance. A positive voltage causes bridging to occur between the two ends, lowering the device’s resistance, and a negative voltage reverses the process, increasing the resistance. The exact formulation of a memristor can vary. The memristor was conceived in the 1970s by Leon Chua, and HP Labs created a working one in 2008. An (expensive) 16-pin DIP was first made available in 2015.

A hafnium oxide memristor is a bit different. Normally it would be write-once, meaning a negative voltage does not reset the device, but researchers discovered that exposing it to gamma radiation appears to weaken the bridging, allowing a negative voltage to reset the device as expected. Exposure to radiation also caused a higher voltage to be required to set the memristor; a behavior researchers were able to leverage into using the memristor to measure radiation exposure. Given time, a hafnium oxide memristor exposed to radiation, causing it to require higher-than-normal voltages to be “set”, eventually lost this attribute. After 30 days, the exposed memristors appeared to recover completely from the effects of radiation exposure and no longer required an elevated voltage for writing. This is the behavior the article refers to as “self-healing”.

The research paper has all the details, and it’s interesting to see new things relating to memristors. After all, when it comes to electronic components it’s been quite a long time since we’ve seen something genuinely new.