Direct 3D printing of metal remains out of reach for the hobbyist at the moment, so casting is often the next best thing, particularly given the limitations of 3D printed metals. [Denny] from Shake the Future shows us how to simplify the process with “print wave metal casting.”

The first step of printing a PLA object will seem familiar to any 3D print to metal process, but the main differentiator here is pouring the investment casting on the printer build plate itself. We like how he used some G-code to shake the build plate to help remove bubbles. Once the plaster solidifies, the plastic and mold are placed in the microwave to soften the plastic for removal.

The plaster is dried in an oven (or air fryer) and then [Denny] bolts the mold together for the casting process. Adding a vacuum helps with the surface finish, but you can always polish the metal with a generous helping of elbow grease.

If [Denny] seems familiar, you might remember his very detailed breakdown of microwave casting. We’ve seen plenty of different approaches to metal casting over the years here. Need a part in another material? How about casting concrete or resin?

Thanks to [marble] on the Hackaday Discord for the tip!

Sometimes, a limb is damaged so badly that the only way to save the patient is to amputate it. Researchers have now found that humans aren’t the only species to perform life-saving amputations. [via Live Science]

While some ants have a gland that secretes antimicrobial chemicals to treat wounds in their comrades, Florida carpenter ants have lost this ability over the course of evolution. Lacking this chemical means to treat wounds, these ants have developed the first observed surgery in an animal other than humans.

When an ant has a wounded leg, its fellow ants analyze the damage. If the femur is the site of the wound, the other ants removed the damaged limb in 76% of cases by biting it off, while tibial wounds were treated in other ways. Experimental amputations of the tibia by researchers showed no difference in survivability compared to leaving the limb intact unless the amputation was performed immediately, so it seems the ants know what they’re doing.

Maybe these ants could be helpful surgical aids with some cyborg additions since they’ve already got experience? Ants can help you with programming too if that’s more your speed.

After decades of taking plastic bags for granted, some places now charge for them to help offset some of the environmental damage they cause. If you have a tendency to forget your reusable bags at home but love to wear hats, [Simone Giertz] has the bag hat for you.

Having conquered everything from making the first Tesla pickup to a tambour puzzle table, a hat that can turn into a grocery bag seems like a relatively easy challenge. It was not. One thing that [Giertz] observes early in the process is that fabric is a much less “honest” material since it can move in ways that many of the other materials she works with cannot, like glass or wood.

As with any good project, there are numerous iterations of the bag hat, mostly due to trying to balance the two distinct functions of bag and hat without overly-compromising either. In the end, the hat features a zipper down the center from ear to ear that opens up into a mesh grocery bag. The adjustable loop of the hat does double duty as the bag handle.

If you’d like to build your own sewing machine for projects like this, maybe you should find out how they work. If you’d rather just get on with the sewing bit, we can help you with that too.

When you first unwrap a shiny new roll of filament for your FDM printer, it typically has a bag of silica gel inside. While great for keeping costs low on the manufacturing side, is silica gel the best solution to keep your filament dry at home?

Frustrated with the consumable nature and fussy handling of silica gel beads, [Build It Make It] sought a more permanent way to keep his filament dry. Already familiar with activated alumina beads, he crafted a desiccant cylinder that can be popped into the oven all at once instead of all that tedious mucking about with emptying and refilling plastic capsules.

A length of aluminum intake pipe, some high temperature epoxy, and aluminum mesh are all combined to make a simple, sealed cylinder. During the process, he found that using a syringe filled with the epoxy led to a much more precise application to the aluminum cylinder, so he recommends starting out that way if you make these for yourself.

We suspect something with a less permanent attachment at one end would let you periodically swap out the beads if you wanted to try this hack with the silica beads you already had. Perhaps some kind of threaded pipe fitting? If you want a more active dryer, try making one with a Peltier. If you want to know just how dry your filament is getting, you could also put in a sensor. You might also wonder, do you really need to dry filament at all?

While EV charging isn’t that tedious with a cable, for quick trips, being able to just park and have your car automatically charge would be more convenient. Researchers from Oak Ridge National Lab (ORNL) and VW have moved high-speed wireless EV charging one step closer to reality.

We’ve seen fast wireless EV chargers before, but what sets this system apart is the coil size (~0.2 m² vs 2.0 m²) and the fact it was demonstrated on a functioning EV where previous attempts have been on the bench. According to the researchers, this was the first wireless transfer to a light duty vehicle at 270 kW. Industry standards currently only cover systems up to 20 kW.

The system uses a pair of polyphase electromagnetic coupling coils about 50 cm (19″) wide to transfer the power over a gap of approximately 13 cm (5″). Efficiency is stated at 95%, and that 270 kW would get most EVs capable of those charge rates a 50% bump in charge over ten minutes (assuming you’re in the lower part of your battery capacity where full speeds are available).

We’ve seen some in-road prototypes of wireless charging as well as some other interesting en route chargers like pantographs and slot car roads. We’ve got you covered if you’re wondering what the deal is with all those different plugs that EVs have too.

When comparing the efficiency of different wind turbine blade designs, [AdamEnt] found using a hair dryer wasn’t the best tool for the job. Enter his new 3D-printed wind tunnel.

After several prototypes, [AdamEnt] decided on a design that exploits slicer infill to create a flow straightener without having to do any tedious modeling of a lattice. Combined with a box on both ends of the straightener to constrain the flow, he has a more controllable air source with laminar instead of turbulent flow for testing his wind turbines.

The BLDC motor driving the air is attached to a toroidal blade of MIT fame. We get a little bit of the math behind calculating wind turbine efficiency and see a quick test of a blade placed next to the outlet of the air source at the end of the video.

If you’re planning on building your own wind tunnel, we’ve covered a few. We’ve even seen one that goes up to Mach 20, although that probably wouldn’t be useful for wind turbine design!

In the course of a career, you may run up against projects that get cancelled, especially those that are interesting, but deemed unprofitable in the eyes of the corporate overlords. Most people would move, but [Ron Avitzur] just couldn’t let it go.

In 1993, in the midst of the transition to PowerPC, [Avitzur]’s employer let him go as the project they were contracted to perform for Apple was canceled. He had been working on a graphing calculator to show off the capabilities of the new system. Finding his badge still allowed him access to the building, he “just kept showing up.”

[Avitzur] continued working until Apple Facilities caught onto his use of an abandoned office with another former contractor, [Greg Robbins], and their badges were removed from the system. Not the type to give up, they tailgated other engineers into the building to a different empty office to continue their work. (If you’ve read Kevin Mitnick‘s Ghost in the Wires, you’ll remember this is one of the most effective ways to gain unauthorized access to a building.)

We’ll let [Avitzur] tell you the rest, but suffice it to say, this story has a number of twists and turns to it. We suspect it certainly isn’t the typical way a piece of software gets included on the device from the factory.

Looking for more computing history? How about a short documentary on the Aiken computers, or a Hack Chat on how to preserve that history?

[Thanks to Stephen for the tip via the Retrocomputing Forum!]

Hacking and making are great fun due to their open ended nature, but being able to try anything can make the task of selecting your next project daunting. [Steph Piper] is here with her Maker Skill Trees to give you a map to leveling up your skills.

Featuring a grid of 73 hexagonal tiles per discipline, there’s plenty of inspiration for what to tackle next in your journey. The trees start with the basics at the bottom and progressively move up in difficulty as you move up the page. With over 50 trees to select from (so far), you can probably find something to help you become better at anything from 3D printing and modeling to entrepreneurship or woodworking.

Despite being spoiled for choice, if you’re disappointed there’s no tree for your particular interest (underwater basket weaving?), you can roll your own with the provided template and submit it for inclusion in the repository.

Want to get a jump on an AI Skill Tree? Try out these AI courses. Maybe you could use these to market yourself to potential employers or feel confident enough to strike out on your own?

[Thanks to Courtney for the tip!]

Human hands are remarkable pieces of machinery, so it’s no wonder many robots are designed after their creators. The amount of computation required to properly attenuate the grip strength and position of a hand is no joke though, so what if you took a tentacular approach to grabbing things instead?

Inspired by ocean creatures, researchers found that by using a set of pneumatically-controlled tentacles, they could grasp irregular objects reliably and gently without having to faff about with machine learning or oodles of sensors. The tentacles can wrap around the object itself or intertwine with each other to encase parts of an object in its gentle grasp.

The basic component of the device is 12 sections “slender elastomeric filament” which dangle at gauge pressure, but begin to curl as pressure is applied up to 172 kPa. All of the 300 mm long segments run on the same pressure source and are the same size, but adding multiple sized filaments or pressure sources might be useful for certain applications.

We wonder how it would do feeding a fire or loading a LEGO train with candy? We also have covered how to build mechanical tentacles and soft robots, if that’s more your thing.

We’ve all been there. You left your Walkman at home and only have your trusty Game Boy. You want to take a break and just listen to some tunes. What to do? [orangeglo] has the answer now with the Orange FM cartridge.

This prototype cart features an onboard antenna or can also use the 3.5 mm headphone/antenna port on the cartridge to boost reception with either a dedicated antenna or a set of headphones. Frequencies supported are 64 – 108 Mhz, and spacing can be set for 100 or 200 kHz to accomodate most FM broadcasts setups around the world.

Older Game Boys can support audio through the device itself, but Advances will need to use the audio port on the cartridge. The Super Game Boy can pipe audio to your TV though, which seems like a delightfully Rube Goldberg-ian way to listen to the radio. Did we mention it also supports RDS, so you’ll know what that catchy tune is? Try that FM Walkman!

Can’t decide between this and your other carts? Try this revolving multi-cart solution. Have a Game Boy that needs some restoration? If it’s due to electrolyte damage, maybe start here?

As the debate rages on about the value of AI-generated art, [Chris Borge] printed his own version of another technology that’s been the subject of debate about what constitutes real art. Meet the camera lucida.

Developed in the early part of the nineteenth century by [William Hyde Wollaston], the camera lucida is a seemingly simple device. Using a prism or a mirror and piece of glass, it allows a person to see the world overlaid onto their drawing surface. This moves details like proportions and shading directly to the paper instead of requiring an intermediary step in the artist’s memory. Of course, nothing is a substitute for practice and skill. [Professor Pablo Garcia] relates a story in the video about how [Henry Fox Talbot] was unsatisfied with his drawings made using the device, and how this experience was instrumental in his later photographic experiments.

[Borge]’s own contribution to the camera lucida is a portable version that you can print yourself and assemble for about $20. Featuring a snazzy case that holds all the components nice and snug on laser cut felt, he wanted a version that could go in the field and not require a table. The case also acts as a stand for the camera to sit at an appropriate height so he can sketch landscapes in his lap while out and about.

Interested in more drawing-related hacks? How about this sand drawing bot or some Truly Terrible Dimensioned Drawings?

While electricity generation has been the star of the energy transition show, about half of the world’s energy consumption is to make heat. Many industrial processes rely on fossil fuels to reach high temps right now, but researchers at ETH Zurich have found a new way to crank up the heat with a solar thermal trap. [via SciTechDaily]

Heating water for showers or radiant floor systems in homes is old hat now, but industrial application of solar power has been few and far between. Part of the issue has been achieving high enough temperatures. Opaque absorbers can only ever get as hot as the incident surface where the sun hits them, but some translucent materials, like quartz can form thermal traps.

In a thermal trap, “it is possible to achieve temperatures that are higher in the bulk of the material than at the surface exposed to solar radiation.” In the study, the researchers were able to get a 450˚C surface to produce 1,050˚C interior temperature in the 300 mm long quartz rod. The system does rely on concentrated solar power, 135 suns-worth for this study, but mirror and lens systems for solar concentration already exist due to the aforementioned electrical power generation.

This isn’t the only time we’ve seen someone smelting on sunlight alone, and you can always do it less directly by using a hydrogen intermediary. If you’re wanting a more domestic-level of heat, why not try the wind if the sun doesn’t shine much in your neighborhood?