Trebuchet Sends Eggs Flying

Without any sort of restrictions on designs for trebuchets, these medieval siege weapons are known to send 90 kilogram projectiles over 300 meters. The egg-launching trebuchet contest that [AndysMachines] is entering, on the other hand, has a few limitations that dramatically decreased the size of the machines involved. The weight of the entire device is limited to no more than 3 kg, with any physical dimension no more than 300 mm, but that’s more than enough to send an egg flying across a yard with the proper design and tuning for maximum distance.

Trebuchets distinguish themselves amongst other siege weapons by using a falling weight to launch the projectile. The rules of this contest allow for the use of springs, so [AndysMachines] is adding a spring in between the trebuchet arm and the weight in order to more efficiently deliver the energy from the falling weight. More fine tuning of the trebuchet was needed before the competition, though, specifically regarding the stall point for the trebuchet. This is the point where the forces acting on the arm from the projectile and the weight are balanced, and moving this point to allow the projectile to release at a 45-degree angle was needed for maximum distance.

The video goes into a lot of detail about other fine-tuning of a trebuchet like this, aided by some slow-motion video analysis. In the end, [AndysMachines] was able to launch the egg over ten meters with this design. Of course, if you want to throw out the rule book and replace the eggs with ball bearings and the aluminum and steel with titanium, it’s possible to build a trebuchet that breaks the sound barrier.

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Laser-Etching Photos On To Eggs

CNC machines are every maker’s dream. Capable of churning out accurate parts from CAD designs with a minimum of manual labor, they’re a great tool to have in the workshop. Alternatively, you can use them for more entertaining pursuits. [Leo]’s project is one of the latter – etching greyscale photos on to eggs.

The first thing you’ll need is an egg-compatible CNC machine. The Eggbot is a popular option, else a fourth-axis on an existing machine can also do the job as in [Leo]’s case. Coupling the egg is a delicate task, for which some rubber paper rollers are salvaged from an old printer and put to work. Then, a laser needs to be fitted to the CNC head, and the egg depth mapped with a probe to ensure the entire etching is in focus. Then it’s simply a matter of loading up an image, and turning the greyscale data into the relevant G-code to burn it onto the egg.

Using eggs coated in black ink, the results [Leo] achieves are impressive. The eggs would make an amusing Easter gift, or serve as a great cheap way to teach students about CNC techniques. Obviously, eye protection is a must, and be sure to mount your laser securely to avoid any unintentional exposures. Video after the break.

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The Strain Of Flu Shot Logistics

Did you get a flu shot this year? How about last year? In a world of next-day delivery and instant downloads, making the yearly pilgrimage to the doctor or the minute clinic feels like an outdated concept. Even if you get your shots free at the office, it’s still a pain to have to get vaccinated every year.

Unfortunately, there’s really no other way to deal with the annual threat of influenza. There’s no single vaccine for the flu because there are multiple strains that are always mutating. Unlike other viruses with one-and-done vaccinations, influenza is a moving target. Developing, producing, and distributing millions of vaccines every year is a massive operation that never stops, or even slows down a little bit. It’s basically Santa Claus territory — if Santa Claus delivered us all from mass epidemics.

The numbers are staggering. For the 2018-19 season, as in last year, there were 169.1 million doses distributed in the United States, up from 155.3 million doses the year before. How do they do it? We’re gonna roll up our sleeves and take a stab at it.

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DIY Ovalia Chair Serves Your Futuristic Fantasies

The 1960s were a heady time, with both society and the language of design undergoing rapid changes over a short period. Back in 1968, Henrik Thor-Larsen exhibited his Ovalia egg chair for the first time, at the Scandinavian Furniture Fair. With original examples now antiques, and with even replicas being prohibitively expensive, it might just be worth considering building your own if you need to have one. Thankfully, [Talon Pascal] leads the way.

It’s a replica that’s built with accessible DIY tools and techniques. The frame is built up from plywood parts, cut out with a jigsaw. These are then assembled with glue and screws, forming two halves of the full-sized egg assembly. The exterior is then covered with thin strips of wood, as opposed to the fiberglass construction of the original. This is smoothed out with a judicious application of wood putty and plenty of sanding. The interior is then lined with foam before the chair is upholstered with red fabric. We’re not sure exactly how the trim ring is fitted, but it gives the chair a nice clean finished edge and rounds out the project nicely. There are even embedded speakers so you can chill out with some tunes in your ovaloid sanctuary.

It just goes to show that there’s value in the old adage – if you can’t buy it, build it! Perhaps, however, you’re outfitting the office – in which case, would something from the Porsche range suffice?

Photochromic Eggs: Not For Breakfast

Photochromic paint is pretty nifty – under exposure to light of the right wavelength, it’ll change colour. This gives it all kinds of applications for temporary displays.  [Jiri Zemanek] decided to apply photochromic paint to an egg, utilising it to create stroboscopic patterns with the help of a laser.

Patterns for the egg are generated in MATLAB. A Discovery STM32 board acts as a controller, looking after the laser scanner and a stepper motor which rotates the egg. A phototransistor is used to sync the position of the laser and the egg as it rotates.

The photochromic paint used in this project is activated by UV light. To energize the paint, [Jiri] harvested a violet laser from a Blu-ray player, fitting it to a scanning assembly from a laser printer. Instead of scanning the laser across an imaging drum, it is instead scanned vertically on a rotating egg. Patterns can then be drawn on the egg, which fade over time as the paint gives up its stored energy.

[Jiri] exploits this by writing a variety of patterns onto the egg, which then animate in a manner similar to a zoetrope – when visualised under strobing light, the patterns appear to move. There are also a few holiday messages shown for Easter, making the egg all the more appropriate as a billboard.

If you like the idea of drawing on eggs but are put off by their non-uniform geometry, check out the Egg-bot. Video below the break.

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An Eggcelent Eggspriment

After multiple iterations [Keef] has nailed down the fabrication process for an unusual component. Using only a heater water bath, some silicone and easily available reagents, [Keef] demonstrate how he manufactures a gastronomic enigma: the long egg.

The similarities between [Keef’s] process and the typical hacker iteration cycle are eggceptional. He starts out with a goal and iterates, modifying his methods until he gets the perfect long egg. Sound familiar? Cooking can be as much of a science as it is an art.

In his quest, [Keef] utilizes sausage casing, plastic bags, sticky tape, “lots of sweat and almost some tears” to hold eggs for cooking via an Anova Precision Cooker immersion circulator. However, [Keef] notes, the Anova is normally used for sous vide cooking so you might not have one sitting around. In that case, you can use a regular pan on a stovetop along with a digital thermometer, but you’ll have to be quite vigilant to keep the temperature steady.

But wait. Why would one want a long egg in the first place? I’ll leave this explanation to [Keef]. “Well, the main use is in a Gala Pie (a long pork pie baked in a loaf tin and often cut into slices for picnics). Or you could just slice the egg and lay it out on a platter and amaze your friends with how every slice is exactly the same size.”

Go check out [Keef’s] two videos. He has two, one that chronicles the eggciting initial attempts, and another that describes his final method. With [Keef’s] help, the number of long eggs outside of Denmark may substantially increase. But, if you’d rather have some pizza, we won’t be offended.

What Came First? The Chicken Or The LASER?

If you’ve had a child in the last few decades, you’ve had a choice to make: if you want to know the sex of the baby ahead of time. With ultrasound you can find out or–popular these days–you can have the result sealed and have a baker create a reveal cake. Apparently, researchers at the Dresden University of Technology and the University of Leipzig wanted to do the same trick with unborn chickens.

You might wonder why anyone cares (we did). Apparently, chickens that are bred for egg laying don’t produce roosters suitable for food use. This leads to about half of the chicks being “culled” (a less ugly euphemism than gassed or shredded) and used in–among other things–animal feed. Worldwide, billions of chicks are culled each year and that’s not counting other similar situations like male turkeys and female ducks.

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