In Praise Of The Proof Of Concept

Your project doesn’t necessarily have to be a refined masterpiece to have an impact on the global hacker hivemind. Case in point: this great demo of using a 64-point time-of-flight ranging sensor. [Henrique] took three modules, plugged them into a breadboard, and wrote some very interactive Python code that let him put them all through their paces. The result? I now absolutely want to set up a similar rig and expand on it.

That’s the power of a strong proof of concept, and maybe a nice video presentation of it in action. What in particular makes [Henrique]’s POC work is that he’s written the software to give him a number of sliders, switches, and interaction that let him tweak things in real time and explore some of the possibilities. This exploratory software not only helped him map out what directions to go, but they also work in demo mode, when he’s showing us what he has learned.

But the other thing that [Henrique]’s video does nicely is to point out the limitations of his current POC. Instantly, the hacker mind goes “I could work that out”. Was it strategic incompleteness? Either way, I’ve been nerd-sniped.

So are those the features of a good POC? It’s the bare minimum to convey the idea, presented in a way that demonstrates a wide range of possibilities, and leaving that last little bit tantalizingly on the table?

Love Complex Automata? Don’t Miss The Archer

[Oliver Pett] loves creating automata; pieces of art whose physicality and motion come together to deliver something unique. [Oliver] also has a mission, and that mission is to complete the most complex automata he has ever attempted: The Archer. This automaton is a fully articulated figure designed to draw arrows from a quiver, nock them in a bow, draw back, and fire — all with recognizable technique and believable motions. Shoot for the moon, we say!

He’s documenting the process of creating The Archer in a series of videos, the latest of which dives deep into just how intricate and complex of a challenge it truly is as he designs the intricate cams required.

A digital, kinematic twin in Rhino 3D helps [Oliver] to choose key points and determine the cam profiles required to effect them smoothly.
In simple automata rotational movement can be converted by linkages to create the required motions. But for more complicated automata (like the pen-wielding Maillardet Automaton), cams provide a way to turn rotational movement into something much more nuanced. While creating the automaton and designing appropriate joints and actuators is one thing, designing the cams — never mind coordinating them with one another — is quite another. It’s a task that rapidly cascades in complexity, especially in something as intricate as this.

[Oliver] turned to modern CAD software and after making a digital twin of The Archer he’s been using it to mathematically generate the cam paths required to create the desired movements and transitions, instead of relying on trial and error. This also lets him identify potential collisions or other errors before any metal is cut. The cams are aluminum, so the fewer false starts and dead ends, the better!

Not only is The Archer itself a beautiful piece of work-in-progress, seeing an automaton’s movements planned out in this way is a pretty interesting way to tackle the problem. We can’t wait to see the final result.

Thanks [Stephen] for the tip!

MicroGPT Lets You Peek With Your Browser

Regardless of what you think of GPT and the associated AI hype, you have to admit that it is probably here to stay, at least in some form. But how, exactly, does it work? Well, MicroGPT will show you a very stripped-down model in your browser. But it isn’t just another chatbot, it exposes all of its internal computations as it works.

The whole thing, of course, is highly simplified since you don’t want billions of parameters in your browser’s user interface. There is a tutorial, and we’d suggest starting with that. The output resembles names by understanding things like common starting letters and consonant-vowel alternation.

At the start of the tutorial, the GPT spits out random characters. Then you click the train button. You’ll see a step counter go towards 500, and the loss drops as the model learns. After 500 or so passes, the results are somewhat less random. You can click on any block in the right pane to see an explanation of how it works and its current state. You can also adjust parameters such as the number of layers and other settings.

Of course, the more training you do, the better the results, but you might also want to adjust the parameters to see how things get better or worse. The main page also proposes questions such as “What does a cell in the weight heatmap mean?” If you open the question, you’ll see the answer.

Overall, this is a great study aid. If you want a deeper dive than the normal hand-waving about how GPTs work, we still like the paper from [Stephen Wolfram], which is detailed enough to be worth reading, but not so detailed that you have to commit a few years to studying it.

We’ve seen a fairly complex GPT in a spreadsheet, if that is better for you.

Electric Jeep With Modified Prius Hardware

On the list of cars widely regarded as the most reliable vehicles ever built, up there with the Toyota Land Cruiser, the Honda Civic, and the Mercedes W123 diesels, is the unassuming Toyota Prius. Although it adds a bit of complexity with its hybrid drivetrain, its design eliminates a number of common wear items and also tunes it for extreme efficiency, lengthening its life and causing minimal mechanical stress. The Prius has a number of other tricks up its sleeve as well, which is why parts of its hybrid systems are often used in EV conversions like [Jeremy]’s electric CJ-5 Jeep.

Inside the Prius inverter is a buck/boost converter used for stepping up the battery voltage to power the inverter and supply power to the electric motor. [Jeremy]’s battery is much higher voltage than the stock Prius battery pack, though, which means he can bypass the converter and supply energy from his battery directly to the inverter. Since the buck/boost converter isn’t being used, he can put it to work doing other things. In this case, he’s using it as a charger. Sending the AC from a standard EV charging cord through a rectifier and then to this converter allows the Prius hardware to charge the Jeep’s battery, without adding much in the way of extra expensive electronics.

There are some other modifications to the Prius equipment in this Jeep, though, namely that [Jeremy] is using an open-source controller as the brain of this conversion. Although this video only goes into detail on some of the quirks of the Prius hardware, he has a number of other videos documenting his journey to convert this antique Jeep over to a useful electric farm vehicle which are worth checking out as well. There are plenty of other useful things that equipment from hybrid and electric vehicles can do beyond EV conversions as well, like being used for DIY powerwalls.

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Displaying The Rainbow

True or false? Your green laser pointer is more powerful than your red one. The answer is almost certainly false. They are, most likely, the same power, but your eye is far more sensitive to green, so it seems stronger. [Brandon Li] was thinking about how to best represent colors on computer screens and fell down the rabbit hole of what colors look like when arranged in a spectrum. Spoiler alert: almost all the images you see of the spectrum are incorrect in some way. The problem isn’t in our understanding of the physics, but more in the understanding of how humans perceive color.

Perception may start with physics, but it also extends to the biology of your eye and the psychology of your brain. What follows is a lot of math that finally winds up with the CIE 1931 color space diagram and the CIE 2012 system.

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Panoramic Film Camera Made From 3D Printed Parts

Even though digital cameras have lowered the barrier of entry to photography dramatically, as well as made it much easier for professionals and amateurs alike to capture stunning images without the burden of developing film, the technology behind them is considerably more complex than their analog counterparts. In fact, an analog film camera (not counting the lens) can be as simple as a lightproof box and a way to activate a shutter. Knowing that, any kind of film camera could be built for any number of applications, like this 3D-printed panoramic camera from [Denis Aminev].

The custom-built camera works by taking a standard roll of 35mm film, which is standardized to take 36 pictures, and exposing a wider section of the film to create a panorama. This reduces the number of pictures on the roll to 19. This is the fifth version of this camera, called the Infidex 176 V, and has everything a standard film camera would have, from an exposure counter, pressure plate for the film, a winder, interchangable lenses, a viewfinder, and a tripod mounting point. It does take a bit of work to assemble, as shown in the video linked below, but the final result is impressive and delivers a custom finished product not easily found or reproducible in off-the-shelf cameras.

The path to creating this camera was interesting as well, as [Denis]’s first custom film camera was a pinhole camera. From there he moved on to disassembling an SLR camera and attempting to reproduce all of its parts with 3D printed ones. With that in hand, he was able to modify this design into this panoramic camera which he likes because it reproduces the feel of widescreen movies. Although this camera reproduces all of the bells and whistles of a high quality analog camera, not all of these features are strictly necessary for taking pictures on film. Have a look at this minimum viable camera as well.

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Porting Super Mario 64 To The Original Nintendo DS

Considering that the Nintendo DS already has its own remake of Super Mario 64, one might be tempted to think that porting the original Nintendo 64 version would be a snap. Why you’d want to do this is left as an exercise to the reader, but whether due to nostalgia or out of sheer spite, the question of how easy this would be remains. Correspondingly, [Tobi] figured that he’d give it a shake, with interesting results.

Of note is that someone else already ported SM64 to the DSi, which is a later version of the DS with more processing power, more RAM and other changes. The reason why the 16 MB of RAM of the DSi is required, is because it needs to load the entire game into RAM, rather than do on-demand reads from the cartridge. This is why the N64 made do with just 4 MB of RAM, which is as much RAM as the NDS has. Ergo it can be made to work.

The key here is NitroFS, which allows you to implement a similar kind of segmented loading as the N64 uses. Using this the [Hydr8gon] DSi port could be taken as the basis and crammed into NitroFS, enabling the game to mostly run smoothly on the original DS.

There are still some ongoing issues before the project will be released, mostly related to sound support and general stability. If you have a flash cartridge for the DS this means that soon you too should be able to play the original SM64 on real hardware as though it’s a quaint portable N64.

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