Whirling Sawblades Turn Foam Packaging Into Wall Insulation

If you’re like us, the expanded polystyrene (EPS) foam inserts that protect many packages these days are a source of mixed feeling. On the one hand, we’re glad that stuff arrives intact thanks to the molded foam inserts. But it seems so wasteful, especially when chucking it in the garbage can. If only it could be effectively recycled.

It turns out that it can be, if you equip yourself with this spinning “sawblades of doom” EPS recycler. It comes by way of [HowToLou], who was looking for a way to insulate a wall on the cheap. Almost all commercially available insulating materials – fiberglass batts, blown-in cellulose, expanding polyisocyanurate – are pretty pricey. Foam packing pieces are pretty easy to come by, though, and usually free for the taking. [Lou]’s method of turning them into insulation is a box containing four circular saw blades mounted to a piece of threaded rod and spun by a cordless drill. The blades are mounted askew on the rod for better reduction of the foam; [Lou] chose to use wire to hold the blades down, while we’d have printed up some slanted arbors and bolted the blades down more firmly. A chicken wire prefilter keeps the big chunks from clogging a blower made from an old bathroom exhaust fan, which does a great job of filling the wall cavities with pulverized EPS nuggets. The video below has all the details.

Honestly, the box is a little scary, and we have doubts that [Lou] will be able to get enough foam to finish the job, but it’s still a clever little hack. Grinding things up seems to be a theme for him; check out his leaf collector or his apple cider press.

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Es’hail-2: Hams Get Their First Geosynchronous Repeater

In the radio business, getting the high ground is key to covering as much territory from as few installations as possible. Anything that has a high profile, from a big municipal water tank to a roadside billboard to a remote hilltop, will likely be bristling with antennas, and different services compete for the best spots to locate their antennas. Amateur radio clubs will be there too, looking for space to locate their repeaters, which allow hams to use low-power mobile and handheld radios to make contact over a vastly greater range than they could otherwise.

Now some hams have claimed the highest of high ground for their repeater: space. For the first time, an amateur radio repeater has gone to space aboard a geosynchronous satellite, giving hams the ability to link up over a third of the globe. It’s a huge development, and while it takes some effort to use this new space-based radio, it’s a game changer in the amateur radio community.

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Hack Chat: The Home Machine Shop with Quinn Dunki

Join us Wednesday at noon Pacific time for the Home Machine Shop Hack Chat!

Even if you haven’t been here for very long, you’ll probably recognize Quinn Dunki as Hackaday’s resident consulting machinist. Quinn recently did a great series of articles on the “King of Machine Tools”, the lathe, covering everything from the history of precision machine tools to making your first chips. She’s documented the entire process of procuring and setting up a new lathe, pointing out all the potential pitfalls the budding home machinist may face. You can get a much deeper dive into her machining adventures on her YouTube channel, Blondihacks.

Flinging hot metal chips around is hardly all Quinn has accomplished, though. Long before her foray into machine tools, there was Veronica, a scratch-built 6502 machine Quinn created as an homage to the machines that launched her into a life of writing software. We’ve featured Veronica on our pages a couple of times, and she’s always made quite a hit.

Please join us for this Hack Chat, where we’ll discuss:

  • How developing software and machining are alike, and how they differ;
  • How social networks have changed the perception of machining;
  • Best practices for getting started in machining; and
  • Are there any new machine tool purchases in the pipeline?

You are, of course, encouraged to add your own questions to the discussion. You can do that by leaving a comment on the Home Machine Shop Hack Chat and we’ll put that in the queue for the Hack Chat discussion.

join-hack-chatOur Hack Chats are live community events on the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, March 20, at noon, Pacific time. If time zones have got you down, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.

EBay Modules And Custom PCBs Make A Plug And Play Ham Transceiver

Many of us have fond memories of our introduction to electronics through the “200-in-1” sets that Radio Shack once sold, or even the more recent “Snap Circuits”-style kits. Most of eventually us move beyond these kits to design our circuits; still, there’s something to be said for modular designs. This complete amateur radio transceiver is a great example of that kind of plug and play construction.

The rig is the brainchild of [jmhrvy1947], who set out to build a complete transceiver using mostly eBay-sourced modules. Some custom PCBs are used, but those are simple boards that can be etched and drilled easily. The transceiver is only for continuous-wave (CW) use, which would normally mean you’d need to know Morse, but thanks to some clever modifications to open-source apps like Quisk and FLDigi, Morse can be received and sent directly from the desktop. That will no doubt raise some hackles, but we think it’s a great way to learn code. The rig is QRP, or low power, transmitting only 100 mW with the small power amp shown. Adding eBay modules can jack that up to a full 100 Watts, which also requires adding a 12-volt power supply, switchable low-pass filters, a buck-boost converter, and some bandpass filters for band selection. It ends up looking very experimental, but it works well enough to make contacts.

We really like the approach here, and the fact that the rig can be built in stages. That makes it a perfect project for our $50 Ham series, which just kicked off. Perhaps we’ll be seeing it again soon.

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The $50 Ham: Entry-Level Transceivers for Technicians

Last week , I covered the ridiculously low barriers to entry to amateur radio, both in terms of financial outlay and the process of studying for and passing the FCC examination. You’ve had seven days, so I assume that you’ve taken the plunge and are a freshly minted amateur radio operator. The next big question may be: Now what?

We briefly mentioned the image that ham radio is a rich old person’s hobby, and that reputation is somewhat deserved. For ham gear, there really is no upper limit on what you can spend. Glossy brochures and slick web pages hawk transceiver bristling with knobs and switches and loaded with the latest features, all of which will probably be obsolete within a few years when the Next Big Thing comes along and manufacturers respond with new, must-have models – looking at you, ICOM IC-7300. It’s no different than any other technology market, and enough people fall for that marketing to make it a going concern.

But thankfully, while there is no apparent ceiling on what you can spend on ham gear, there certainly is a floor, and it can be very, very low. Our $50 budget can go quite a long way to getting a new Technician on the air, if you’re willing to make some compromises and can forego the latest and greatest for a while.

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[Ben Krasnow] Drills Really Small Holes with Electricity

Drilling holes is easy; humans have been doing it in one form or another for almost 40,000 years. Drilling really tiny holes in hard materials is more challenging, but still doable. Drilling deep, straight holes in hard materials is another thing altogether.

Luckily, these days we have electric discharge machining (EDM), a technique that opens up all kinds of possibilities. And just as luckily, [Ben Krasnow] got his hands on some EDM gear to try out, with fascinating results. As [Ben] explains, at its heart EDM is just the use of a small arc to ablate metal from a surface. The arc is precisely controlled, both its frequency via an arc controller, and its location using CNC motion control. The arc controller has always been the sticking point for home EDM, but the one [Ben] tried out, a BaxEDM BX17, is squarely aimed at the small shop market. The whole test platform that [Ben] built has a decidedly home-brew look to it, with a CNC gantry rigged up to a water tank, an EDM drill head spinning the drill rods slowly, and an airless paint gun providing high-pressure process fluid. The video below shows that it works remarkably well nonetheless.

While we’re certainly keen to see [Ben]’s promised videos on EDM milling and cutting, we doubt we’ll line up to shell out €2,950 for the arc controller he used. If you have more courage than money, this mains-powered EDM might be a better fit.

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Simple Sensor Provides Detailed Motion Capture for VR Hands

Consider the complexity of the appendages sitting at the end of your arms. The human hands contain over a quarter of the entire complement of bones in the body, use dozens of muscles both in the hand itself and extending up the forearm, and are capable of almost infinite variance in the movements they can create. They are exquisite machines.

And yet when it comes to virtual reality, most simulations treat the hands like inert blobs. That may be partly due to their complexity; doing motion capture from so many joints can be computationally challenging. But this pressure-sensitive hand motion capture rig aims to change that. The product of an undergraduate project by [Leslie], [Hunter], and [Matthew], the idea was to provide an economical and effective way to capture gestures for virtual reality simulators, which generally focus on capturing large motions from the whole body.

The sensor consists of a sandwich of polyurethane foam with strain gauge sensors embedded within. The user slips his or her hand into the foam and rests the fingers on the sensors. A Teensy and twenty lines of code translate finger motions within the sandwich into five axes of joystick movement, which is then sent to Unreal Engine, where finger motions were translated to a 3D-model of a hand to play a VR game of “Rock, Paper, Scissors.”

[Leslie] and her colleagues have a way to go on this; testers complained that the flat hand posture was unnatural, and that the foam heated things up quickly. Maybe something more along the lines of these gesture-capturing gloves would work?