2025-09-07 04:00:13
Weekends can be busy for a lot of us, but sometimes you have one gloriously free and full of possibilities. If that’s you, you might consider taking a gander at [Peter Shirley]’s e-book “Learning Raytracing in One Weekend”.
This is very much a zero-to-hero kind of class: it starts out defining the PPM image format, which is easy to create and manipulate using nearly any language. The book uses C++, but as [Peter] points out in the introduction, you don’t have to follow along in that language; there won’t be anything unique to C++ you couldn’t implement in your language of choice.
There are many types of ray tracers. Technically, what you should end up with after the weekend ends is a path tracer. You won’t be replacing the Blender Cycles renderer with your weekend’s work, but you get some nice images and a place to build from. [Peter] manages to cram a lot of topics into a weekend, including diffuse materials, metals, dialectrics, diffraction, and camera classes with simple lens effects.
If you find yourself with slightly more time, [Peter] has you covered. He’s also released books on “Raytracing: The Next Week.” If you have a lot more time, then check out his third book, “Raytracing: The Rest of Your Life.”
This weekend e-book shows that ray-tracing doesn’t have to be the darkest of occult sciences; it doesn’t need oodles of hardware, either. Even an Arduino can do it..
2025-09-07 01:00:32
When making a personal website, one will naturally include a personal touch. What could be more personal than creating a font from your own handwriting? That’s what [Chris Smith] has done, and it looks great on his blog, which also has a post summarizing the process.
Like most of us [Chris] tried to use open-source toolkits first, but the workflow (and thus the result) was a bit wanting. Still, he details what it takes to create a font in Inkscape or Font Forge if anyone else wants to give it a try. Instead he ended up using a web app called Calligraphr designed for this exact use case.
Fair warning: the tool is closed-source and he needed to pay to get all the features he wanted — specifically ligatures, glyphs made from two joined letters. By adding ligatures his personalized font gets a little bit of variation, as the ‘l’ in an ‘lf’ ligature (for example) need not be identical to the stand-alone ‘l’. In a case of “you get what you pay for” the process worked great and to the credit of the folks at Calligraphr, while it is Software-As-Service they offer a one-time payment for one month’s use of the “pro” features. While nobody likes SaS, that’s a much more user-friendly way to do it — or perhaps “least-user-hostile”.
All [Chris] had to do was write out and scan a few sheets that you can see above, while the software handled most of the hard work automagically. [Chris] only had to apply a few tweaks to get the result you see here. Aside from websites, we could see a personalized font like this being a nice touch to laser cut, CNC or even 3D printed projects. If you don’t want a personalized touch, the “Gorton” lettering of retro machinery might be more to your liking.
2025-09-06 22:00:23
We like to think that we can do almost anything. Give me a broken piece of consumer electronics, and I’ll open it up and kick the capacitors. Give me an embedded Linux machine, and I’ll poke around for a serial port and see if it’s running uboot. But my confidence suddenly pales when you hand me a smartphone.
Now that’s not to say that I’ve never replaced a broken screen or a camera module with OEM parts. The modern smartphone is actually a miracle of modularity, with most sub-assemblies being swappable, at least in principle, and depending on your taste for applying heat to loosen up whatever glue holds the damn things together.
But actually doing hardware hacking on smartphones is still outside of my comfort zone, and that’s a shame. So I was pretty pleased to see [Marcin Plaza] attempt gutting a smartphone, repackaging it into a new form factor, and even adding a new keyboard to it. The best moment in that video for me comes around eight minutes in, when he has completely disassembled all of the modules and is laying them out on his desk to see how little he needs to make the thing work. And the answer is batteries, motherboard, USB-C, power button, and a screen. That starts to seem like a computer build, and that’s familiar turf.
That reminded me of [Scotty Allen]’s forays into cell-phone hackery that culminated in his building one completely from parts, and telling us all about it at Supercon ages ago. He told me that the turning point for him was realizing that if you have access to the tools to put it together and can get some of the impossibly small parts manufactured and/or assembled for you, that it’s just like putting a computer together.
So now I’ve seen two examples. [Scotty] put his together from parts, and [Marcin] actually got a new daughterboard made that interfaces with the USB to add a keyboard. Hardware hacking on a cellphone doesn’t sound entirely impossible. You’d probably want a cheap old used one, but the barrier to entry there isn’t that bad. You’ll probably have to buy some obscure connectors – they are tiny inside smartphones – and get some breakout boards made. But maybe it’s possible?
Anyone have more encouragement?
2025-09-06 19:00:31
Designer furniture generally comes with excellent aesthetics and (sometimes) functionality. However, such furniture comes with a price to match. One such piece of furniture is the Magis Spun Chair. It’s a striking piece with a fun party trick to match: it works like a top spinning while you sit inside. However, it has a prohibitively expensive price tag of $1,200 to match. That’s why [Morley Kert] is on a mission to build one for less.
This isn’t [Morley]’s first time building a spinning chair. The first attempt featured numerous 3D printed pieces glued together. It did not inspire confidence in spinning, nor was it a striking piece of furniture. So a revisit was in order.
This time around the chair’s construction was CNC milled plywood. Some surfaces featured 3D carving, but the majority were left raw with carving the final shape handled manually. Despite its size, the chair only took four and a half sheets of 3/4 inch plywood by hollowing out the base allowing for more efficient use of material. Once the router had completed the pieces, they were stacked and glued together. Each layer was aligned with hidden dowels making the assembly process fairly straightforward.
However, while usable, the chair looked rather unfinished, so [Morley] went to town on it with a power carving angle grinder. To ensure even carving on the circular profile of the chair, he placed it, or for some sections glued it, on an electronic lazy S. After some practice, the carving process turned out really well with a well-shaped and professional looking chair. Some wood varnish and a large amount of sanding finished up the chair very nicely for a total material cost of under $500.
We were happy to see the completion of this chair building saga. If you want to see [Morley] make even more designer furniture for cheap, make sure to check out his other 3D printed chair!
2025-09-06 16:00:37
Ever tear open a potentiometer? If you haven’t, you can still probably guess what’s inside. A streak of resistive material with some kind of contact that moves across it as you rotate the shaft, right? Usually, you’d be right, but [T. K. Hareedran] writes about a different kind of pot: ones that use magnetic sensing.
Why mess with something simple? Simplicity has its price. Traditional units may not be very accurate, can be prone to temperature and contamination effects, and the contact will eventually wear out the resistive strip inside. However, we were a little curious about how a magnetic potentiometer could offer a resistive output. The answer? It doesn’t.
Really, these would be better described as rotary encoders with a voltage output. They aren’t really potentiometers. The SK22B mentioned in the article, for example, requires a 5 V input and outputs somewhere between 10% and 90% of that voltage on the ersatz wiper pin.
That makes the devices much easier to puzzle out. The linearity of a device like that is better than a real pot, and, of course, the life expectancy is greatly increased. On the other hand, we’d rather get one with quadrature or I2C output and read it digitally, but if you need a voltage, these devices are certainly an option.
[T. K.] goes on to show how he fabricated his own non-contact sensor using photosensors and a gray-coded wheel with a single track. You do need to be careful about where you position the sensors, though.
Could you make a real non-contact resistive pot? Seems like you could get close with an FET output stage, but it wouldn’t be as generally applicable as a good old-fashioned smear of carbon. If you have a better idea, drop it in the comments or build it and give us a tip.
Want a 20A-capable device? Build it. Want to see how we like to read encoders?
2025-09-06 13:00:31
For something non-explosive, this might be the most American project we’ve featured in a while. [Makerinator]’s domestic bliss was apparently threatened by the question “what shall we have for dinner”– that’s probably pretty universal. Deciding that the solution was automation is probably universal to software devs and associated personalities the world over. That the project, aptly called “The Decisioninator” apes a popular game-show mechanic to randomly select a fast-food restaurant? Only people with 100-octanes of freedom running through their veins can truly appreciate its genius.
In form factor, it’s a tiny slot machine which [Makerinator] fabbed up on his laser cutter. The lovely “paintjob” was actually a print out with dye-sublimation ink that was transferred to plywood before laser cutting. Mounted to this are illuminated arcade buttons and a small ISP display. The interface is simplicity itself: the big button spins a virtual “wheel” on the display (with sound effects inspired by The Price is Right) to tell the family what deliciously unhealthy slop they’ll be consuming, while the other button changes decision modes. Of course you can pick more than just dinner with The Decisioninator. You need only decide what spinners to program. Which, uh, that might be a problem.
Luckily [Makerinator] was able to come up with a few modes without recursively creating a The Decisioninator-inator. He’s got the whole thing running on a Pi4, which, with its 1980s supercomputer performance, is hilariously overpowered for the role it plays (in true American fashion). He’s coded the whole thing in the Flame Engine, which is a game engine built on the Flutter UI toolkit by American technology giant Google.
What’s more American than tech giants and fast food? A propane powered plasma cannon, for one thing; or maybe mental gymnastics to translate into freedom units, for another.
Thanks to [Makerinator] for the tip.
