Raspberry Pi Cluster Shows You The Ropes

Raspberry Pi clusters are a common enough project, but a lot of the builds we see focus on the hardware side of the cluster. Once it’s up and running, though, what comes next? Raspberry Pis aren’t very powerful devices, but they can still be a great project for learning how to interact with a cluster of computers or for experimental test setups. In this project from [Dino], four Pis are networked together and then loaded with a basic set of software for cluster computing.

The first thing to set up, after the hardware and OS, is the network configuration. Each Pi needs a static IP in order to communicate properly. In this case, [Dino] makes extensive use of SSH. From there, he gets to work installing Prometheus and Grafana to use as monitoring software which can track system resources and operating temperature. After that, the final step is to install Ansible which is monitoring software specifically meant for clusters, which allows all of the computers to be administered more as a unit than as four separate devices.

This was only part 1 of [Dino]’s dive into cluster computing, and we hope there’s more to come. There’s a lot to do with a computer cluster, and once you learn the ropes with a Raspberry Pi setup like this it will be a lot easier to move on to a more powerful (and expensive) setup that can power through some serious work.

Gain An Understanding Of Injection Molding’s Design Gotchas

When it comes to manufacturing, sheet metal and injection molding make the world go ’round. As a manufacturing method, injection molding has its own range of unique design issues and gotchas that are better to be aware of than not. To help with this awareness, [studiored] has a series of blog posts describing injection molding design issues, presented from the perspective of how to avoid and address them.

Design of screw bosses demonstrating conflict between molder’s guidelines and vendor’s recommendations. Compromising between both is a science and an art.

Because injection molding involves heat, warp is one issue to be aware of and its principles will probably be familiar to anyone with nitty-gritty experience in 3D printing. Sink marks are also an issue that comes down to differential cooling causing problems, and can ruin a smooth and glossy finish. Both of these play a role in how best to design bosses.

Minimizing and simplifying undercuts (similar to overhangs in 3D printer parlance) is a bit more in-depth, because even a single undercut means much more complex tooling for the mold. Finally, because injection molding depends on reliably molding, cooling, and ejecting parts, designing parts with draft (a slight angle to aid part removal) can be a fact of life.

[studiored] seems to have been working overtime on sharing tips for product design and manufacture on their blog, so it’s worth keeping an eye on it for more additions. We mentioned earlier that much of the manufacturing world revolves around injection molding and sheet metal, so to round out your knowledge we published a primer on everything you need to know about the art and science of bending sheet metal. With a working knowledge of the kinds of design issues that affect these two common manufacturing methods, you’ll have a solid foundation for any forays into either world.

Teaching Science With An Empty Soda Bottle

Creating the next generation of scientists and engineers starts by getting kids interested in STEM at an early age, but that’s not always so easy to do. There’s no shortage of games and movies out there to entertain today’s youth, and just throwing a text book at them simply isn’t going to cut it anymore. Modern education needs to be engrossing and hands-on if it’s going to make an impact.

Which is exactly what the Institute of Science and Technology Austria hopes to accomplish with the popSCOPE program. Co-founded by [Dr. Florian Pauler] and [Dr. Robert Beattie], the project uses off-the-shelf hardware, 3D printed parts, and open source software to create an engaging scientific instrument that students can build and use themselves. The idea is to make the experience more personal for the students so they’re not just idle participants sitting in a classroom.

The hardware in use here is quite simple, essentially just a Raspberry Pi Zero W, a camera module, a Pimoroni Blinkt LED module, and a few jumper wires. It all gets bolted to a 3D printed frame, which features a female threaded opening that accepts a standard plastic soda (or pop, depending on your corner of the globe) bottle. You just cut a big opening in the side of the bottle, screw it in, and you’ve saved yourself a whole lot of time by not printing an enclosure.

So what does the gadget do? That obviously comes down to the software it’s running, but out of the box it’s able to do time-lapse photography which can be interesting for biological experiments such as watching seeds sprout. There’s also a set of 3D printable “slides” featuring QR codes, which the popSCOPE software can read to show images and video of real microscope slides. This might seem like cheating, but for younger players it’s a safe and easy way to get them involved.

For older students, or anyone interested in homebrew scientific equipment, the Poseidon project offers a considerably more capable (and complex) digital microscope made with 3D printed parts and the Raspberry Pi.

MakerBot Targets Schools With Rebranded Printers

MakerBot was poised to be one of the greatest success stories of the open source hardware movement. Founded on the shared knowledge of the RepRap community, they created the first practical desktop 3D printer aimed at consumers over a decade ago. But today, after being bought out by Stratasys and abandoning their open source roots, the company is all but completely absent in the market they helped to create. Cheaper and better printers, some of which built on that same RepRap lineage, have completely taken over in the consumer space; forcing MakerBot to refocus their efforts on professional and educational customers.

This fundamental restructuring of the company is perhaps nowhere more evident than in the recent unveiling of “SKETCH Classroom”: an $1,800 package that includes lesson plans, a teacher certification program, several rolls of filament, and two of the company’s new SKETCH printers. It even includes access to MakerBot Cloud, a new online service that aims to help teachers juggle student’s print jobs between multiple SKETCH printers.

Of course, the biggest takeaway from this announcement for the average Hackaday reader is that MakerBot is releasing new hardware. Their last printer was clearly not designed (or priced) for makers, and even a current-generation Replicator costs more than the entire SKETCH Classroom package. On the surface, it might seem like this is a return to a more reasonable pricing model for MakeBot’s products; something that could even help them regain some of the market share they’ve lost over the years.

There’s only one problem, MakerBot didn’t actually make the SKETCH. This once industry-leading company has now come full-circle, and is using a rebranded printer as the keystone of their push into the educational market. Whether they were unable to build a printer cheap enough to appeal to schools or simply didn’t want to, the message is clear: if you can’t beat them, join them.

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Journey Through The Inner Workings Of A PCB

Most electronics we deal with day to day are comprised of circuit boards. No surprise there, right? But how do they work? This might seem like a simple question¬†but we’ve all been in the place where those weird green or black sheets are little slices of magic. [Teddy Tablante] at Branch Eduction put together a lovingly crafted walkthrough flythrough video of how PCB(A)s work that’s definitely worth your time.

[Teddy]’s video focuses on unraveling the mysteries of the PCBA by peeling back the layers of a smartphone. Starting from the full assembly he separates components from circuit board and descends from there, highlighting the manufacturing methods and purpose behind what you see.

What really stands out here is the animation; at each step [Teddy] has modeled the relevant components and rendered them on the PCBA in 3D. Instead of relying solely on hard to understand blurry X-ray images and 2D scans of PCBAs he illustrates their relationships in space, an especially important element in understanding what’s going on underneath the solder mask. Even if you think you know it all we bet there’s a pearl of knowledge to discover; this writer learned that VIA is an acronym!

If you don’t like clicking links you can find the video embedded after the break. Credit to friend of the Hackaday [Mike Harrison] for acting as the best recommendation algorithm and finding this gem.

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The Ifs Make Learning To Code Child’s Play

Anyone who has done the slightest bit of programming knows about the “Hello, World!” program. It’s the archetypal program that one enters to get a feel for a new language or a new architecture; if you can get a machine to print “Hello, World!” back to you, the rest is just details. But what about teaching kids to program? How does one get toddlers thinking in logical, procedural ways? More particularly, what’s a “Hello, World!” program look like for the pre-literate set?

Those are the sort of questions that led to The Ifs by [Makeroni Labs]. The Ifs are educational toys for teaching kids as young as three the basics of coding. Each If is a colorful plastic cube with a cartoon face and a “personality” that reflects what the block does – some blocks have actuators, some have sensors. The blocks are programmed by placing magnetic tabs on the top representing conditions and actions. A kid might choose to program a block to detect when it’s being shaken, or when the lights come on, and then respond by playing a sound or vibrating. The blocks can communicate with each other too, so that when the condition for one block is satisfied, something happens on another block.

The Ifs look like a lot of fun, and they’re a great jumpstart on the logical thinking skills needed for coders and non-coders alike. We’re not alone in thinking this is a pretty keen project – the judges for this year’s Hackaday Prize selected The Ifs as one of the twenty finalists. Will it win? We’ll find out next week at the 2019 Hackaday Superconference. If you won’t be in Pasadena with us, make sure you tune in to the livestream to watch the announcement.

Spin Me Right Round, Baby: Generator Building Experiments For Mere Mortals

How many of you plan to build a wind-powered generator in the next year? Okay, both of you can put your hands down. Even if you don’t want to wind your coils manually, learning about the principles in an electric generator might spark your interest. There is a lot of math to engineering a commercial model, but if we approach a simple version by looking at the components one at a time, it’s much easier to understand.

For this adventure, [K&J Magnetics] start by dissect a commercial generator. They picked a simple version that might serve a campsite well, so there is no transmission or blade angle apparatus to complicate things. It’s the parts you’d expect, a rotor and a stator, one with permanent magnets and the other with coils of wire.

The fun of this project is copying the components found in the commercial hardware and varying the windings and coil count to see how it affects performance. If you have ever wound magnet wire around a nail to make an electromagnet, you know it is tedious work so check out their 3D printed coil holder with an embedded magnet to trigger a winding count and a socket to fit on a sewing machine bobbin winder. If you are going to make a bunch of coils, this is going to save headaches and wrist tendons.

They use an iterative process to demonstrate the effect of multiple coils on a generator. The first test run uses just three coils but doesn’t generate much power at all, even when spun by an electric drill. Six windings do better, but a dozen finally does the trick, even when turning the generator by hand. We don’t know about their use of cheap silicone diodes though, that seems like unintentional hobbling, but we digress.

Making turbine blades doesn’t have to be a sore chore either, and PVC may be the ticket there, you may also consider the vertical axis wind turbine which is safer at patio level. Now, you folks building generators, remember to tip us off!

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