Photography Goes Leaf Green

August 28, 2023 by Jenny List 4 Comments

Something that haunts film photographers is the prospect of a film shortage. This won’t replace film in that event, but [Applied Science] demonstrates photography using leaves. That’s right, a plant can record an image on its leaves.

Anyone with a high-school level of education can tell you that the leaf is a solar energy harvester, with the green chlorophyll using CO2 scavenged from the air to make sugars in the presence of light. It stands to reason that this light sensitivity could be used to capture images, and indeed if you place a leaf in the dark for an extended period of time its chlorophyll fades away where there is no light. The technique described in the video below the break is different though, and much more sensitive than the days-long exposures required to strip chlorophyll. It relies on starch, which the leaf uses to store energy locally when it has an excess of light. Continue reading “Photography Goes Leaf Green” →

Kitchen Steganography With Turmeric

August 26, 2023 by Al Williams 12 Comments

It is a classic rite of passage for nerdy kids to write secret messages using lemon juice. If you somehow missed that, you can’t see the writing until you heat the paper up with, say, an old-fashioned light bulb. If you were a true budding spy, you’d write a boring normal letter with wide spacing and then fill in the blanks between the lines with your important secrets written in juice. This is a form of steganography — encoding secret messages by hiding them in plain sight. [Randomona] shares a different technique that seems to be way cooler than lemon juice using, of all things, turmeric. This isn’t like the invisible ink of our childhood.

That’s probably a good thing. We doubt an LED bulb makes enough heat to develop our old secret messages. [Ranomona’s] ink doesn’t use heat, but it uses a developer. That means you must make two preparations: the ink and the developer. The results are amazing, though, as shown in the video below.

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A wooden frame with 64 green LEDs running a Game of Life simulation

Wooden CNC Sculpture Displays Conway’s Game Of Life

August 24, 2023 by Robin Kearey 1 Comment

Conway’s Game of Life has been the object of fascination for computer hobbyists for decades. Watching the generations tick by is mesmerizing to watch, but programming the data structure and implementing the rules is also a rewarding experience, especially if you’re just getting acquainted with a new computing platform. Just as rewarding can be creating a nice piece of hardware to run the game on, as [SandwichRising] has just done: check out his beautiful wooden Game of Life implementation.

The main part of his Game is a piece of poplar wood that was CNC routed to produce an 8×8 display adorned with neat chain-like shapes. The display consists of standard 5 mm green LEDs, but they’re not the things you see poking out the front of the wooden frame. Instead, what you’re seeing are 64 lenses made out of epoxy. [SandwichRising] first covered the holes with tape, then poured green epoxy into each one and waited for it to harden. He then took off the tape and applied a drop of UV-cured epoxy on top to create a lens.

All the LEDs are mounted on PCB strips that are hooked up to a central bus going to the main ATmega328P microcontroller sitting on a separate piece of PCB. Whenever the system is powered on, the game is set to a random state determined by noise, after which the simulation begins. On such a small field it’s pretty common for the game to end up in a stable state or a regular oscillation, which is why the ATmega keeps track of the last few dozen states to determine if this has happened, and if so, reset the game to a random state again.

The source code, as well as .STL files for the PCBs and the frame, are available in the project’s GitHub repository. If woodworking isn’t your thing, there’s plenty of other ways to make neat Game of Life displays, such as inside an alarm clock, with lots of LEDS under a coffee table, or even with a giant flip-dot display.

3D Printing With Clay, Thanks To Custom Extruder

August 22, 2023 by Donald Papp 14 Comments

When it comes to 3D printing clay, there are a lot of challenges to be met. An extruder capable of pushing clay is critical, and [davidsfeir] has an updated version suitable for an Ender 3 printer. This extruder is based on earlier designs aimed at delta printers, but making one compatible with an Ender 3 helps keep things accessible.

Lightly pressurized clay comes in via the clear tube. Air escapes out the top (motor side) while an auger homogenizes the clay and pushes it out the nozzle.

What’s special about a paste extruder that can push clay? For one thing, clay can’t be stored on a spool, so it gets fed into the extruder via a hose with the help of air pressure. From there, the clay is actually extruded with the help of an auger that takes care of pushing the clay down through the nozzle. The extruder also needs a way to deal with inevitable air bubbles, which it does by allowing air to escape out the narrow space at the top of the assembly while clay gets fed downward.

[davidsfeir] was greatly inspired by the work of clay-printing pioneers [Piotr Waśniowski] and his de-airing clay extruder, and [Jonathan Keep], who has documented 3D printing with clay comprehensively in a freely-available PDF. You can check out more of [david]’s designs on his Instagram page.

There are so many different aspects to printing with clay or clay-like materials that almost every part is ripe for innovation. For example, we’ve seen wild patterns result from sticking a thumping subwoofer under a print bed.

A Speaker With Dancing Ferrofluid

August 14, 2023 by Al Williams 2 Comments

A speaker project isn’t usually very different, but we couldn’t help but notice [Electronoob’s] latest speaker not for its audio performance but because it features dancing ferrofluid and is an unusual work of art. The housing is 3D printed and includes some translucent portions for LEDs.You can see and hear the speaker at work in the video below.

Apparently, not all ferrofluid is created equal. You can get just the fluid, but then you have to work up some sort of carrier fluid. You can also get the material already in a glass with a carrier fluid, which is a better option. Apparently, you can also get cheap material that is little more than iron filings suspended in a liquid. That’s not really ferrofluid.

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Hacking Fake Food

August 8, 2023 by Al Williams 24 Comments

Ever seen a restaurant where they display fake models of the food on the menu? We never thought much about how shokuhin sampuru — the Japanese name — were made until we watched [Process X]’s video showing a 71-year-old artist creating food models. We aren’t sure what we — or you — would do with this information, but it is a striking process, and there must be something you could do with it. We suggest turning on the English captions, but you’d probably enjoy watching the unusual craftsmanship even with no words.

In years past, the food models were primarily made from wax, but since the 1980s, it is more common to use polyvinyl chloride, silicone, and resin. While some factories produce items, sometimes with a mold, single craftsmen like the one in the video still make up the largest part of the market.

We aren’t sure, but we think the material in the video is wax. We couldn’t help but think that some of this could have been 3D printed, but even with the finest resins and resolution, it probably wouldn’t be quite as artistic. We think wax is mainly underutilized in today’s tech. But there are some places it still shows up.

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This Kinetic Art Display Uses A Gin Bottle

August 7, 2023 by Dave Rowntree 8 Comments

[David McDaid] likes gin. So in homage to their favourite tipple, a certain brand of Scottish origin, a kinetic art project was brewed. Tabled as a Rube Goldberg machine — it’s not — but it is a very smart marble run type installation, dripping with 3D printed parts and a sprinkling of blinkenlights.

The write-up shows the degree of pain we go through with building such contraptions, apparently [David] burned through 2.5 kg of PLA filament despite the bill of materials requiring a mere 660 g. Much experimentation, trial and error, and plenty of print-and-reprint-until-good-enough, resulted in a clean looking run with some neat features. We particularly like the use of a stainless steel jigger to add a touch of metallic ting, to the soundscape produced. The whole show was put together in Fusion 360, since all those tight tolerances do not make for a simple construction without a lot of fiddling around with the layout. Once it was a sound, layout was prototyped on a wood board, which was subsequently used a drill template for the final acrylic version.

On the electronics side of things, an Arduino Nano clone is on control duty, reading an IR trip sensor to fire of a simple light effect, illuminating the gin bottle in a slick fashion. These machines need a mechanism to raise the balls against that pesky force of gravity, in this instance a 3D printed custom chain was constructed, driven with a stepper motor in turn driven from a TMC2208. You see, this thing lives in the kitchen, so the aim was to keep all the noise from the mechanics to a minimum so only the noise of LDPE balls rattling around can be heard. They are the star of the show after all! The build looks nice and would certainly be something we’d like to see on the wall. Obviously we’ve seen a few marble runs over the years. Here’s an interesting one that uses an elevator mechanism, and another project that shows how to generate runs procedurally.

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