Author: Navarre Bartz

256 Articles

A large, short set of tree stumps supports many smaller, straight trees atop them. They are on a picturesque mountain with a orange deciduous tree behind them.

Daisugi – Growing Straight Lumber Without Killing The Tree

February 20, 2024 by 30 Comments

In 14th Century Japan, there was a shortage of straight lumber for building and flat land on which to grow it. Arborists there developed a technique that looks like growing trees on top of trees, called daisugi.

Similar to the European practice of pollarding for firewood and basket materials, daisugi has been likened to bonsai on steroids. Starting with a Japanese cedar tree, one chops the top off the tree once it has grown to sufficient size to survive this initial shock. The following spring, you start carefully guiding the new growth through pruning to create tall, straight trunks on top of the “platform cedar.” Pruning takes place approximately every two years and harvesting every twenty. A daisugi tree can produce new shoots for several hundred years if properly maintained.

Although often used as a decorative technique today, it seems like an interesting way to grow your own perfect lumber if you have the room for it. We suspect the technique could be used on other species that lend themselves to pollarding like oak or maple, but harvest times and reliable straight trunks might vary. With sustainable production of wood for cross-laminated timber (CLT) and other advanced timbers being of growing importance, we wonder if these techniques could make a comeback?

Continue reading “Daisugi – Growing Straight Lumber Without Killing The Tree” →

A white man with red hair in pigtails under a brown cap holds an axe with a black head and wooden handle. The axe has a rectangular box welded onto the back side of its trapezoidal head.

Deadblow Axe Splits Wood With Minimal Rebound

February 16, 2024 by 17 Comments

Dead-blow hammers are well-known in the construction industry for minimizing rebound. [Jacob Fischer] is on a mission to bring this concept to splitting axes.

Over the course of several months, [Fischer] has been working on adding a dead-blow to a splitting axe. This fifth iteration uses a custom-forged head from blacksmith [Todd Elder] with a dead-blow box welded to the poll. The combination of the head geometry and the dead-blow distributing the delivery of force seems to result in a very effective splitting axe.

The dead-blow portion of the axe is a steel box filled with lead (Pb) BBs. Since the BBs are trailing the axe head within the box, the force from the BBs is delivered later than the initial impact of the steel axe head onto the block of wood, allowing the full force of the blow to be spread out over more time. Dead-blow hammers typically use polymers to further absorb any rebound energy, so there is some limit to the extent rebound can be reduced as seen in the testing portion of the video.

Looking for other ways to split wood? How about this cross-bladed axe or maybe a log splitter or two? If you’re curious about how they used to make axes in the old days, we’ve got you covered there too.

Continue reading “Deadblow Axe Splits Wood With Minimal Rebound” →

An image of a cave drawing of horned cow. There is another one coming up behind it as well. There are four dots as described by the researchers on the main cow's back.

Writing – So Easy A Caveperson Could Do It

February 13, 2024 by 10 Comments

We modern humans tend to take writing for granted, and often forget that like any other technology, somebody had to invent it. Researchers from Cambridge believe they’ve determined the purpose of one of the earliest writing beta-tests.

Examining a database of images taken in caves throughout Europe and dated to the Upper Paleolithic, the researchers found “three of the most frequently occurring signs—the line <|>, the dot <•>, and the <Y>—functioned as units of communication.”

It appears the <|> and <.> symbols when “in close association with images of animals” denote time relating to lunar months of the year, starting with spring as the new year. The <Y> symbol appears to carry the meaning <To Give Birth> allowing early people a way to tell others information about the prey of a region, which would be pretty handy when hunting and gathering are your only options for food.

We’ve covered other ancient technologies like storytelling and abrasives. If you’re curious what the climate was like for our ancestors, perhaps paleoclimatology will tickle your fancy.

A render of the Melodio Self Mate music player with it's front plate removed. It's a grey device with a small screen and navigation wheel, similar to a chunky iPod. It has an IR blaster LED in the top and various exposed screw holes letting everyone know that this is a device you can open.

Melodio Self Mate

February 12, 2024 by 25 Comments

While the proliferation of the smartphone has caused the personal music player (PMP) market to mostly evaporate, there are still those who prefer a standalone device for their music. The Melodio Self-Mate is one such spiritual successor to the iPod.

Music-only devices really benefit from the wheel interface pioneered by Apple, so we still see it in many of the new Open Source PMPs including this one and the Tangara. The Melodio uses the ubiquitous ESP32 for its brains coupled with a TI PCM5102A DAC and TI TPA6130A2 headphone amp for audio. A slider on the side of the device allows you to switch it between mass storage mode and programming mode for the ESP32.

Since this device packs a little more horsepower and connectivity than the original iPods, things like listening to Spotify are doable once assembled, instead of having to completely rebuild the device. Speaking of building, there are only renders on the GitHub, so we’re not sure if this project has made the jump IRL yet. With more people concerned about the distractions of smartphones, maybe this renaissance of open PMPs will lead to a new golden age of music on the go?

Miss the halcyon days of the iPod? They’re easier to hack now than ever, and if you really want to go old school, how about a podcast on a floppy?

Droplet Watch Keeps Time Via Electrowetting

February 9, 2024 by 7 Comments

Hackers just can’t help but turn their sights on timepieces, and [Armin Bindzus] has designed an electrowetting-based watch.

Electrowetting is a way of changing the contact angle of droplets on a surface using electricity, and can be used to move said droplets. The liquid needs to be polar, so in this case [Bindzus] has used a red ink mixed with mono-ethylene glycol to stand out against the white dielectric back of the device. The 60 individual electrodes of the bottom section were etched via laser out of the ITO-coated glass that makes up the bottom plates of the face.

The top plate houses the small round pillars that keep the ink constrained to its paths. They are made of a photosensitive epoxy that is spin-coated onto the glass and then cured via the laser. The plates are put together at a distance of 0.23 mm with epoxy, but a small hole is left to insert the droplets and a filler liquid. An Attiny1614 microcontroller runs the show along with a DS3231 RTC. A 46V signal drives the droplets around their path.

It seems this project is a bit away from true wearable use, but perhaps [Bindzus] could make a desk clock first? If you’re interested in another ink-based, watch, how about this custom E-Ink Tank watch?

Continue reading “Droplet Watch Keeps Time Via Electrowetting” →

A line-art diagram of the microfluidic device. On the left, in red text, it says "Fibrillization trigger (CPB pH 5.0). There is a rectangular outline of the chip in grey, with a sideways trapezoid on the left side narrowing until it becomes an arrow on the right. At the right is an inset picture of the semi-transparent microfluidic chip and the text "Negative Pressure (Pultrusion)." Above the trapezoid is the green text "MaSp2 solution" and below is "LLPS trigger (CPB pH 7.0)" in purple. The green, purple, and red text correspond with inlets labeld 1, 2, and 3, respectively. Three regions along the arrow-like channel from left to right are labeled "LLPS region," "pH drop," and in a much longer final section "Fiber assembly region."

Synthetic Spider Silk

February 8, 2024 by 7 Comments

While spider silk proteins are something you can make in your garage, making useful drag line fibers has proved a daunting challenge. Now, a team of scientists from Japan and Hong Kong are closer to replicating artificial spider silk using microfluidics.

Based on how spiders spin their silk, the researchers designed a microfluidic device to replicate the chemical and physical gradients present in the spider. By varying the amount of shear and chemical triggers, they tuned the nanostructure of the fiber to recreate the “hierarchical nanoscale substructure, which is the hallmark of native silk self-assembly.”

We have to admit, keeping a small bank of these clear, rectangular devices on our desk seems like a lot less work than keeping an army of spiders fed and entertained to produce spider silk Hackaday swag. We shouldn’t expect to see a desktop microfluidic spider silk machine this year, but we’re getting closer and closer. While you wait, why not learn from spiders how to make better 3D prints?

If you’re interesting in making your own spider silk proteins, checkout how [Justin Atkin] and [The Thought Emporium] have done it with yeast. Want to make your spider farm spiders have stronger silk? Try augmenting it with carbon.

A child in a red shirt and blue pants balances on a board suspended across two small, green sawhorses. An astroturf hill and blue elephant-esque cart are in the background.

Popup Playground Roams Around

February 4, 2024 by 4 Comments

Going to the park is a time-honored pastime for kids around the world, but what if there isn’t one nearby? COMPA Teatro Trono and the International Design Clinic have designed a park that can come to you.

Working with a group of design students from Bolivia and America, the theatre troupe has iteratively designed a set of playground carts that can be deployed for kids to meet each other and play. El Alto, the city of 1 million where the playground plies the streets, has grown exponentially since its incorporation as an independent town in 1985. Infrastructure has trouble catching up with population jumps of 54% like that experienced from 2000-2010.

Starting with interviews with kids from the city about what was important for a playground, they found a trend of trees, slides, and the color green. Over the course of three summers, the design students went from janky prototypes to the more refined carts now seen roaming El Alto built around the idea of “exaggerated topography.” An elephant and “astroturf bee” are the two hand carts which disassemble into a variety of playground equipment once in place at a destination.

Not a ton of details are given in the article about the construction of the carts themselves, but we think this tactical urbanist approach to parks is a hack in itself. That said, be sure to point us toward some more info on the builds if you’ve found any. Know of another hack, that brings joy to your own neighborhoods? Send it to the tipsline!