3D Printing Food University Style

While refitting a 3D printer for food printing isn’t really a new idea, we liked the detailed summary that appeared from a team from the University of Birmingham which converted an i3 clone printer to use a syringe extruder.

The syringe in question was meant for veterinarian use and is made of metal. The paper suggests that the metal is a better thermal conductor, but it was’t clear to us if they included a heating element for the syringe. In the pictures, though, it does appear to have some insulation around it. In any case, we imagine a metal syringe is easier to keep clean, which is important if you are depositing something edible.

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Check Soil Moisture At A Glance With This Useful Display

Keeping soil moist is key to keeping most plants happy. It can be a pain having to dip one’s fingers into dirty soil on the regular, so it’s desirable to have a tool to do the job instead. [Andrew Lamchenko] built a capable soil moisture monitor, and equipped it with an E-ink display for easy readings at a glance.

The device is built around the NRF52810 or other related NRF52 microcontrollers, which run the show. Rather than using an off-the-shelf sensor to determine soil conditions, an LMC555CMX timer chip is used, a variant of the classic 555 timer designed for low power consumption. Combined with the right PCB design, this can act as a moisture sensor by detecting capacitance changes in the soil. The sensor is also able to send data using the MySensor protocol, allowing it to be used as a part of a home automation system.

The soil is tested periodically with the moisture sensor, and displayed on the attached e-ink screen. Since the e-ink display requires no electricity except when rewriting the display, this allows the sensor to operate for long periods without using a lot of battery power. The soil can be checked, the display updated, and then the entire system can be put to sleep, using tiny amounts of power until it’s time to test the soil again.

It’s a great example of design for low power applications, where component selection really is everything. We’ve featured [Andrew]’s projects before; he’s long been a fan of using e-ink displays to create long-lasting, low power budget sensor platforms. Video after the break.

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Just How Water Resistant Is The Casio F91W?

Water resistance is an important feature of a modern watch. It makes wearing the watch far more practical in this modern world of sudden rainstorms and urban water balloon ambushes. The Casio F91W, one of the company’s most popular watches, is claimed to be water resistant to “30 meters”, which in ISO parlance, means it is suitable for splashes and rain resistance only. [Rostislav Persion] wanted to get a better idea of what this really meant, so set about investigating for himself.

The first step was to simply immerse the watch under 5.5″ of cold tap water while pressing the buttons and observing for any signs of water ingress. Already, the watch proved it is far more than just rain resistant, so [Rotislav] decided to disassemble the watch and learn how it achieved this.

Disassembly revealed that the watch’s case was entirely sealed, except for three buttons. The buttons, however, are specially designed in order to seal with the plastic case of the watch. Each button consists of a stainless steel pin, machined to be larger on the outside-facing side than the inside. The buttons also have a rubber O-ring seal to allow them to move in the case without allowing water to leak inside. [Rotislav] then compares the simple design to buttons used on watches with higher water resistance ratings, which boast multiple O-ring seals and more complex designs.

Given [Rotislav’s] results, we’d be far more confident getting our affordable Casio watches a little wet. Obviously, we wouldn’t expect to make a warranty claim if damage occurred from use outside the specs, but it’s clear the watch is far more capable than standards might suggest. If that’s not enough though, you can always set about modifying the watch to improve its water resistance even further.

Formula 1 TV Broadcasting In 1:87 Scale

[Gerrit Braun], co-founder of the [Miniatur Wunderland] model railway and miniature airport attraction in Hamburg, takes his model building seriously. For more than five years, he and his team have been meticulously planning, testing, and building a 1:87 scale of Formula 1’s Monaco Grand Prix. Models at the Wunderland are crafted to the Nth detail and all reasonable efforts, and some unreasonable ones, are taken to achieve true-to-life results. In the video down below, part of Gerrit’s diary of the project, he discusses the issues and solutions to simulating realistic television broadcasts (the video is in German, but it has English language subtitles).

The goal is to model the large billboard-sized monitor screens set up at viewing stands. In real life, these displays are fed with images coming in from cameras located all over the circuit, the majority of which are operated by a cameraman. The miniaturization of cameras has come a long way in recent years — the ESP32-CAM module or the Raspberry Pi cameras, for example. But miniaturizing the pan-and-tilt actions of a cameraman, while perhaps possible, would not be reliable over the long time (these exhibits at Wunderland are permanent and operate almost daily). Instead, the team is able to use software to extract a cropped window from high-resolution video, and moving the position of this cropped window simulates the pointing of the camera. More details are in the video.

The skill and creativity of [Gerrit] and his team is incredible. Other videos on this project cover topics like the sound system, PCB techniques used for the roads, and the eye-popping use of an electric standing desk to lift an entire city block so workers can gain access to the area. Fair warning — these are addictive, and the video below is #76 of an unfinished series. We wrote about Wunderland back in 2016 when [Gerrit] and his twin brother [Frank] teamed with Google Maps to make a street view of their replica cities. Thanks to [Conductiveinsulation] who sent us the tip, saying that the discussion about interconnected triangular PCB tiles on this week’s Podcast #122 reminded him of this for some reason. Have any of our readers visited Miniatur Wunderland before? Let us know in the comments below.

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Do You SpaceAPI?

Here at Hackaday we’re privileged to be part of a global community of hackers, makers, technology enthusiasts and creative people whose collective works make our daily news feeds such a fascinating read. We encounter you all directly in the physical world rather the virtual one at the many events across the community, or at the various hackerspaces we visit on our travels. But how can we keep track of the world of hackerspaces when there are so many? Maybe SpaceAPI might hold the answer.

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Hackaday Podcast 123: Radioactive Rhinos, Wile E. Coyote Jetpack, Radio Hacks 3-Ways, And Battery Welders On The Spot

Hackaday’s Mike Szczys is taking a bit of vacation this week, so Elliot is joined by Staff Writer Dan Maloney to talk about all the cool hacks and great articles that turned up this week. Things were busy, so there was plenty to choose from, but how would we not pick one that centers around strapping a jet engine to your back to rollerskate without all that pesky exercise? And what about a light bulb that plays Doom – with a little help, of course. We’ll check out decals you can make yourself and why the custom keyboard crowd might want to learn that skill, learn about the other “first computer”, and learn how a little radiation might be just what it takes to save an endangered species.

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct download (55 MB or so.)

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LED Matrix Glasses Built With The Help Of Graph Paper

These days, there’s all manner of addressable LEDs out there that can be easily used to produce blinky, flashy projects. However, there’s nothing stopping makers from doing things the old fashioned way, and hacking together an matrix out of raw LEDs. [Deepak Khatri] did just that with his own custom build.

Rather than rely on a PCB or other substrate to hold the matrix together, [Deepak] elected to freeform the design instead. A matrix of holes was cut in a cardboard template with the aid of graph paper. LEDs were then inserted into the holes in the requisite pattern, and their own leads soldered together to create the frame for the glasses. Additional wires that were needed were then installed, doubling as a bridge to allow the glasses to rest comfortably on the nose. Black epoxy was then used on the back side to block the light from blinding the wearer. The matrix is controlled by a pair of shift registers addressed by a microcontroller, and the display animates impressively smoothly.

it’s a fun build, and one that we suspect looks particularly impressive at night. They’d also make it easy for your friends to spot you in a dark club. We’ve seen some impressively stylish LED glasses over the years, too, dating all the way back to [macetech]’s pair from 2012. Video after the break.

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