Screenshot from the video showing comparisons between diffused light pictures at different brightnesses and diffusers applied

LED Diffusers Confusing? Organize A Practical Contest

November 3, 2022 by 8 Comments

We all want a nice and shiny LED strip that doesn’t actually look like it consists of individual LEDs – a bar of uniform light is just that much more attractive. There’s all kinds of diffusion options available out there, but they can be confusing – sometimes you’d just like to know, which one is better? If there’s one thing that could easily settle this, it’s a practical test, and that’s what [The Hook Up] has devised for us to learn from.

First off, he talks about LED strips available – between 30, 60 and 144 LED per meter variations, the latter is going to be easier to diffuse than the former. From there, there’s a few different kinds of diffuser covers and aluminum profiles you can get, and [The Hook Up] pairs them in combinations, filming them from a distance and giving us concise visuals of how each combination works at different duty cycles, as well as making brightness measurements every now and then to evaluate losses of different diffuser layers. He proposes a simple rule – when picking a diffuser, distance between the LEDs and the diffuser has to be larger than the between-LED distance, and experiments confirm that. In the end, one of the takeaways is that the differences between 60LED/m and 144LED/m strips are not significant enough that they can’t be compensated for with a decent diffuser.

Continue reading “LED Diffusers Confusing? Organize A Practical Contest” →

M.2 For Hackers – Connectors

November 3, 2022 by 9 Comments

In the first M.2 article, I’ve described real-world types and usecases of M.2 devices, so that you don’t get confused when dealing with various cards and ports available out there. I’ve also designed quite a few M.2 cards and card-accepting adapters myself. And today, I’d like to tell you everything you need to know in order to build M.2 tech on your own.

There’s two sides to building with M.2 – adding M.2 sockets onto your PCBs, and building the PCBs that are M.2 cards. I’ll cover both of these, starting with the former, and knowing how to deal with M.2 sockets might be the only thing you ever need. Apart from what I’ll be describing, there’s some decent guides you can learn bits and pieces from, like the Sparkfun MicroMod design guide, most of which is MicroMod-specific but includes quite a few M.2 tips and tricks too.

First, Let’s Talk About The Y-Key

What could you do with a M.2 socket on your PCB? For a start, many tasty hobbyist-friendly SoMs and CPUs now have a PCIe interface accessible, and if you’re building a development board or a simple breakout, an M.2 socket will let you connect an NVMe SSD for all your high-speed low-power storage needs – many Raspberry Pi Compute Module mainboards have M.2 M-key sockets specifically for that, and there’s NVMe support in the RPi firmware to boot. Plus, you can always plug a full-sized PCIe adapter or an extender into such a socket and connect a PCIe network card or other much-needed device – even perhaps, an external GPU! However, as much as PCIe-equipped SoMs are tasty, they’re far from the only reason to use M.2 sockets.

Continue reading “M.2 For Hackers – Connectors” →

End Of An Era, As LEGO To Discontinue Mindstorms

November 3, 2022 by 46 Comments

When there are so many single board computers and other products aimed at providing children with the means to learn about programming and other skills, it is easy to forget at time before the Arduino or the Raspberry Pi and their imitators, when a computer was very much an expensive closed box.

Into this late-’90s vacuum left in the wake of the 8-bit home computer revolution came LEGO’s Mindstorms kits, a box of interlocking goodies with a special programmable brick, which gave kids the chance to make free-form computerized robotic projects all of their own. The recent news that after 24 years the company will discontinue the Mindstorms range at the end of the year thus feels like the end of an era to anyone who has ridden the accessible microcontroller train since then.

What became Mindstorms has its roots in the MIT Media Lab’s Programmable Brick project, a series of chunky LEGO bricks with microcontrollers and the Mindstorms LEGO brick contacts for motors and sensors. Their Logo programming language implementation was eschewed by LEGO in favor of a graphical system on a host computer, and the Mindstorms kit was born. The brand has since been used on a series of iterations of the controller, and a range of different robotics kits.

In 1998, a home computer had morphed from something programmable in BASIC to a machine that ran Windows and Microsoft Office. Boards such as Parallax’s BASIC Stamp were available but expensive, and didn’t come with anything to control. The Mindstorms kit was revolutionary then in offering an accessible fully programmable microcontroller in a toy, along with a full set of LEGO including motors and sensors to use with it.

We’re guessing Mindstorms has been seen off by better and cheaper single board computers here in 2022, but that doesn’t take away its special place in providing ’90s kids with their first chance to make a proper robot their way. The kits have found their place here at Hackaday, but perhaps most of the projects we’ve featured using them being a few years old now underlines why they are to meet their end. So long Mindstorms, you won’t be forgotten!

Header image: Mairi, (CC BY-SA 3.0).

Heirloom Knife Will Carve Pumpkins For Years To Come

November 3, 2022 by 6 Comments

Halloween may be behind us, but that just means that we’ve reached the best time to buy pumpkins. After all, it’s still fall, and there are pies to be made and tables to be decorated. Why should carved-up pumpkins be restricted to spooky season?

The only problem is that it’s 2022, and we’re still expected to use those terrible little serrated knives to carve our pumpkins. Those orange-handled garbage ‘knives’ are hardly suited to cut the lid, much less carve any of the intricate designs that come in the little booklet. So what’s a pumpkin-carving enthusiast to do? If you’re [XYZ Create], you make your own out of walnut, maple, and a gently-used jigsaw blade that’s still way sharp enough to tear through pumpkin flesh.

[XYZ Create] started with a nice chunk of walnut, which he split lengthwise in order to insert the blade, which sits in a cavity within a thin piece of maple. Once [XYZ Create] had the handle ready to go, he inserted the jigsaw blade and epoxied the sandwich together. After sanding down the edges to make a comfortable grip, he finished off the build by rubbing a bit of carving board wax into the handle. Check out the build video after the break.

Continue reading “Heirloom Knife Will Carve Pumpkins For Years To Come” →

Roll The Radioactive Dice For Truly Random D&D Play

November 2, 2022 by 22 Comments

When you have a bunch of people gathered around a table for a “Dungeons & Dragons” session, you have to expect that things are not always going to go smoothly. After all, people who willingly create and immerse themselves in an alternate reality where one bad roll of the dice can lead to the virtual death of a character they’ve spent months or years with can be traumatic. And with that trauma comes the search for the guilty — it’s the dice! It’s always the dice!

Eliminating that excuse, or at least making it statistically implausible, is the idea behind this radioactively random dice roller. It comes to us from [Science Shack] and uses radioactive decay to generate truly random numbers, as opposed to the pseudorandom number generators baked into most microcontrollers. The design is based on [AlphaPhoenix]’s muon-powered RNG, but with a significant twist: rather than depending on background radiation, [Science Shack] brought the power of uranium to the party.

They obtained a sample of autunite, a weird-looking phosphate mineral that contains a decent amount of uranium, perfect for stimulating the Geiger counter built into the dice roller. Autunite also has the advantage of looking very cool under UV light, taking on a ghostly “fuel rod glow,” in the [Homer Simpson] sense. The decay-powered RNG at the heart of this build is used to simulate throws of every standard D&D die, from a D4 to a D100. The laser-cut hardboard case holds all the controls and displays, and also has some strategically placed openings to gaze upon its glowing guts.

We really like the design, but we have to quibble with the handling of the uranium ore; true, the specific activity of autunite is probably pretty low, but it seems like at least some gloves would have been in order.

Continue reading “Roll The Radioactive Dice For Truly Random D&D Play” →

Breakers for the system on a DIN rail, with markings like 48V and 24V and 12V and so on on the bottom, and two hefty devices of some kind on the bottom, probably MPTT controllers, with hefty wires running from them.

Low-Voltage DC Network Build Incited By Solar Panels

November 2, 2022 by 51 Comments

Nowadays, some people in Europe worry about energy prices climbing, and even if all the related problems disappear overnight, we’ll no doubt be seeing some amounts of price increase. As a hacker, you’re in a good position to evaluate the energy consuming devices at your home, and maybe even do something about them. Well, [Peter] put some solar panels on his roof, but couldn’t quite figure out a decent way to legally tie them into the public grid or at least his flat’s 220V network. Naturally, a good solution was to create an independent low-voltage DC network in parallel and put a bunch of devices on it instead!

He went with 48V, since it’s a voltage that’s high enough to be efficient, easy to get equipment like DC-DCs for, safe when it comes to legal matters concerned, and overall compatible with his solar panel setup. Since then, he’s been putting devices like laptops, chargers and lamps onto the DC rail instead of having them be plugged in, and his home infrastructure, which includes a rack full of Raspberry Pi boards, has been quite content running 24/7 from the 48V rail. There’s a backup PSU from regular AC in case of overcast weather, and in case of grid power failures, two hefty LiFePO4 accumulators will run all the 48V-connected appliances for up to two and a half days.

The setup has produced and consumed 115kWh within the first two months – a hefty contribution to a hacker’s energy independence project, and there’s enough specifics in the blog post for all your inspiration needs. This project is a reminder that low-voltage DC network projects are a decent choice on a local scale – we’ve seen quite viable proof-of-concept projects done at hackercamps, but you can just build a small DC UPS if you’re only looking to dip your feet in. Perhaps, soon we’ll figure out a wall socket for such networks, too.

A Raspberry Pi 3 with a black Raspberry Pi Camera PCB on top of it, looking at the camera taking this picture. There's a Jolly Wrencher in the background.

Make Your Pi Moonlight As A Security Camera

November 2, 2022 by 22 Comments

A decade ago, I was learning Linux through building projects for my own needs. One of the projects was a DIY CCTV system based on a Linux box – specifically, a user-friendly all-in-one package for someone willing to pay for it. I stumbled upon Zoneminder, and those in the know, already can tell what happened – I’ll put it this way, I spent days trying to make it work, and my Linux skills at the time were not nearly enough. Cool software like Motion was available back then, but I wasn’t up to the task of rolling an entire system around it. That said, it wouldn’t be impossible, now, would it?

Five years later, I joined a hackerspace, and eventually found out that its CCTV cameras, while being quite visually prominent, stopped functioning a long time ago. At that point, I was in a position to do something about it, and I built an entire CCTV network around a software package called MotionEye. There’s a lot of value in having working CCTV cameras at a hackerspace – not only does a functioning system solve the “who made the mess that nobody admits to” problem, over the years it also helped us with things like locating safety interlock keys to a lasercutter that were removed during a reorganization, with their temporary location promptly forgotten.

Being able to use MotionEye to quickly create security cameras became quite handy very soon – when I needed it, I could make a simple camera to monitor my bicycle, verify that my neighbours didn’t forget to feed my pets as promised while I was away, and in a certain situation, I could even ensure mine and others’ physical safety with its help. How do you build a useful always-recording camera network in your house, hackerspace or other property? Here’s a simple and powerful software package I’d like to show you today, and it’s called MotionEye.

Continue reading “Make Your Pi Moonlight As A Security Camera” →