Mysterious Files PH

Ever since wealthy European landowners started displaying vast, unused swaths of turfgrass as status symbols, regular folk have been chasing that perfectly mown and tended lawn for similar reasons. In the modern era, most mowers used to maintain these spaces use a spinning blade attached to a motor of some sort, but this can be dangerous especially on rocky fields like [Greenhill Forge] needs to mow. For these fields it’s best to use a different type of mower, and he’s built one from scratch.

This type of mower is called a flail mower, which has hinged, sharpened hammers attached to a central rotating drum. Since the flails have less rotational speed at the ends, they are less dangerous if they strike solid objects like rocks. To build one, he first builds the central drum and flails, then the enclosure to mount it to his tractor, and then a drivetrain to attach it to the tractor’s PTO. Since everything is getting built in [Greenhill Forge]’s metalworking shop, many of the parts needed to be fabricated from scratch, which involved several jigs for the plasma cutter as well as forging some steel to make some of the thicker parts.

Although not many of us have fully-stocked metalworking shops like this, it shows that almost anything can be built with the right tools. A forge is actually fairly accessible for those looking to start smithing; we’ve seen them built from little more than an off-the-shelf unmodified microwave or from a propane torch and some cookware.

When using older computers there comes a point at which modern software drops support, as for example is happening with builds for Windows XP. Every now and then though, along comes something that bucks the trend. Enter [mplsllc] with Macsurf, a port of the Netsurf browser for classic MacOS 9 on PowerPC. Bring your nineties beige box back online!

The first generation of PowerPC Macs occupy an odd position, being faster and more capable than their predecessors while not sharing the ability to run MacOS X like their G3 descendants. Macsurf has the promise of bringing them into the 2020s, but if you’re expecting the equivalent of Google Chrome you might be disappointed.

Netsurf is a browser that started life on RiscOS, the original ARM OS from the Acorn Archimedes. It’s lightweight and portable, it’s an active project, it has a good rendering engine that does up to date HTML and CSS, it offers native TLS, and it has JavaScript built in. It’s ideal for a 1990s PowerPC, but with the caveat that sites expecting the very latest browsers might struggle. Sadly we don’t have a ’90s Mac to hand so we can’t try this port, but we’re used to it on other lower-power machines so we thing it’ll be a great asset to the platform.

We last looked at Netsurf when we had a look at RiscOS, if you are interested.

Elliot Williams is out where the deer and the antelope play for the next week, so it’s up to Tom Nardi and Al Williams to wrangle this episode of the Hackaday Podcast. They’ll start off by reading some listener messages before talking about the slow extinction of time broadcasts, Linux on cheap smartphones, microcontroller VPNs, and the computers of Spacelab.

You’ll also hear about using a video game’s “Photo Mode” to capture 3D imagery, strange red lights in deep space, and ASCII fish that you don’t need to feed. The episode wraps up with a discussion of WWII spy tech and the revelation that modern smartphones and powerful magnets don’t always mix.

Check out the links if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct download in DRM-free MP3.

Episode 371 Show Notes:

Mailbag:

• Linux Fu: The Cheap Macropad Conundrum
• GitHub – islcom/peismo: A simple seismograph for Raspberry Pi · GitHub

Interesting Hacks of the Week:

• So Long, CHU, And Thanks For All The Time Signals
  • What Will You Do If WWVB Goes Silent?
  • Radio Station WWV: All Time, All The Time
  • CHU broadcast codes – National Research Council Canada

• A Zinc Air Battery You Can Make Yourself
  • Electric Vehicle 1900’s Style: New Leases On Old Tech

• Linux On Android Provides Inexpensive, Powerful Computing
  • Want A Low-cost ARM Platform? Grab A Prepaid Android Phone!
  • Linux Fu: The Linux Android Convergence
  • Lindroid Promises True Linux On Android

• Z386: An Open-Source 80386 Built Around Original Microcode
• Running A VPN Gateway On An ESP32
• Spacelab’s Mitra 125 MS
  • Slicing and Dicing the Bits: CPU Design the Old Fashioned Way

Quick Hacks:

• Tom’s Picks:
  • Extract 3D Video Game Content By Firing Up Photo Mode
  • DecayDock Keeps Track Of Spoilage
  • Adorable ASCII Aquarium Lives On Your Desk
• Al’s Picks:
  • Figuring Out What James Webb’s Mysterious Little Red Dots Are
  • Power From Gravity
  • Building An Analog Meter Watch

Can’t-Miss Articles:

• Magnets Are Bad For Hardware Again
• Spy Tech: A Quiet Radio For Spies

For a certain kind of intricate, highly-detailed manufacturing, there’s really no substitute for a resin 3D printer, and it’s therefore unfortunate that they require so many poisonous chemicals. The resin itself usually contains irritating acrylates and methacrylates, it can emit a wide spectrum of volatile organic compounds (VOCs) during printing, and even the isopropyl alcohol used in cleaning is moderately toxic. [Allie Katz] accordingly built this fume-control enclosure for resin printing and other ventilation-critical processes.

The biggest constraint was space: [Allie]’s workspace had a fairly limited volume available, and the enclosure needed to hold an SLA printer, an isopropyl alcohol washing station, a UV curing chamber, and miscellaneous supplies. Most of the enclosure was made out of IKEA cabinets, using some large cabinets at the base to hold the printer and curing station, a countertop over these to hold the washing station, and more cabinets above to hold supplies. An MDF backing panel and acrylic side panels enclose the workspace between the cabinets. There was no safe way to exhaust fumes, so the enclosure recycles its air: a fan pulls air in through an activated-carbon filter mounted above the work area and into the plenum behind the chamber, from which it passes through the printer’s cabinet back into the workspace enclosure. Panel filters surround the carbon filter to catch particulate matter.

The enclosure uses four ESP32-based boards for automation: one uses a touchscreen to display data, and three are paired with BME680 sensors, primarily to report VOC concentrations. One, which also has a particulate matter sensor, senses air quality in the main chamber and plenum, one monitors air quality in the rest of the shop, and the third detects clogging from within the filter enclosure. The first real test of the chamber was to 3D print and paint some handles for the cabinets. It worked as expected, detecting the increased VOCs and ramping up the fan to keep them in check.

We’ve seen a ventilated printer enclosure before, that time for an FDM printer. Although their hazards are less blatant, they too can produce dangerous fumes, which could possibly be carcinogenic.

Thanks to [Keith Olson] for the tip!

The fjords of Norway are world famous for their beauty, but even though the word itself is Norwegian, there are fjords all over the world in areas that used to be covered in glaciers. One of these areas is the Pacific Northwest of North America, we herit’s actually possible to travel by boat from the Seattle area all the way into Alaska without going to the Pacific Ocean, and although plenty of people make this journey by boat, [Matt] is planning on doing this journey on a jet ski with a custom camper on the back.

Normally a jet ski wouldn’t be the ideal platform for a multi-day on-boat adventure because of their size, but [Matt] found perhaps the largest jet ski ever made and he got a deal on it since it had previously been wrecked. Once he repaired the hull damage, he cut a sheet of plywood in half and put a hinge in the middle so it can unfold over the top of the jet ski but fold it away when he’s traveling. With the basic concept in place he took it right out on the water to a campsite before finalizing the construction of the rest of the tent, including the installation of a door, a window, and some interior lighting.

During that first night, a storm cropped up and pushed the craft out to shore while [Matt] was sleeping, so after realizing, waking up, and motoring back to shore, he made sure to tie the craft to a rock to avoid similar situations before going back to sleep. But besides some motion sickness which prevented him from cooking inside his camper, the rest of the adventure went off without a hitch. Before taking it on the Inside Passage he has been thinking of a few improvements like outriggers to keep it from rocking while he sleeps. [Matt] is no stranger to unusual camper builds, though, we recently featured his other camper which is an electric car converted to explore abandoned railroads.

While designing anything for operation in space has its challenges, there is at least one thing that is more of a problem for objects in Earth orbit than for deep-space probes: atomic oxygen. We like oxygen because we need it to live, but it is also highly reactive as a single atom. Luckily, on Earth, most of what we breathe is O₂. [Space Daily] talks about the challenges of the International Space Station dealing with the “space weather” of atomic oxygen in low Earth orbit.

Part of the problem is that even when we know better, we tend to think of the atmosphere coming to an abrupt end and space being a hard vacuum. But in reality, the atmosphere gradually dissipates, and at “only” 400 km above the Earth, the Space Station is really flying through a very thin atmosphere.

To compound the problem, this is above the ozone layer, so the Sun’s UV light rips O₂ into single oxygen atoms. Over time, these free oxygen atoms can affect many parts of a spacecraft exposed to them. Engineers first noticed that materials recovered from spacecraft had more damage and changes to material properties on the pieces facing the direction of travel. NASA has spent years testing different materials by mounting trays of different material samples outside the ISS.

Carbon-based polymers take a big hit from atomic oxygen exposure. Polymide film is frequently used, but it erodes with exposure. Carbon composites also lose mass. Other materials change in other ways. For example, an optical surface may roughen with exposure.

The usual answer is to over-design for mission objectives or to cover certain polymers with coatings like silicon dioxide or aluminum oxide, which are not as reactive to free oxygen. For a long-duration mission like the ISS, you may have to pay special attention to the materials in use. Very low satellites also need special care, as there is more oxygen in lower orbits.

There are other effects, too, such as extreme thermal cycles, debris strikes, and other indignities that space-traveling materials must withstand. But in deep space, atomic oxygen is a rare issue. Until, at least, we go somewhere else that has a lot of oxygen.

We don’t need to tell you: lasers are awesome. Those tiny red beams aren’t just for frustrating cats, but can do real work, be a source of infinite beauty, or constitute a science project in its own right — and you can win a $150 DigiKey gift certificate simply by writing your project up on Hackaday.io. The contest runs until July 23rd.

Of course, red lasers are only the beginning. If you have enough energy to move electrons into higher orbitals, you can make nearly anything lase. RGB setups can be breathtaking. Powerful IR and UV lasers are real tools. And the DIY side of lasering combines physics and electronics, with a spicy side of danger that needs to be contained.

We love laser builds of all sorts, and we’d like to see yours! Create a new Hackaday.io project that features what you’re working on, and we’ll pick our three favorites for a $150 gift certificate courtesy of this contest’s sponsor, DigiKey.

Honorable Mention Categories:

• Lightshow: A laser on its own makes a beam, but there’s so much more to a laser show than just a dot on the wall. If you’ve made your own projector, an RGB setup, or even something super simple with a spinning mirror, show it off here. We’re looking to see laser light beauty, and the machines that make it possible.

• DIY: This category is for the laser DIYers out there. If you made your own laser or laser support equipment, be it a TEA laser from scratch, or just a constant current driver to run a diode you salvaged from a projector, we want to see it. Have you resurrected an esoteric old device? Mixed up your own dyes? This category is all about the laser.

• With Remaining Eye: Lasers are not all fun and games; they can also do real work. If you’ve built a power laser project, or any functional device that relies on a laser to get the job done, it’s eligible here. Laser cutters, safety setups, data transfer over the light beam?  Any laser project that’s not about just looking good fits in here.

If you like to play with the coherent beams, head on over to Hackaday.io and detail your project — and don’t forget to enter it into the contest via the pulldown menu on the left side. If you win, you’ll have $150 to spend on more lasers. (We see you, with our remaining eye.)