RFID Music Player Gets The Whole House Pumping

February 13, 2021 by Lewin Day 11 Comments

RFID tags are normally used for pedestrian tasks like tracking shipping crates or opening doors to workplaces we’d rather be absent from, but they can also be cool and fun. [hoveeman] demonstrates this ably with a tidy jukebox project.

The build is based on a Raspberry Pi Zero, secreted away underneath a table with a USB RFID reader attached. Atop the table are a series of RFID cards upon which [hoveeman] printed the artwork from his favorite albums using a special caddy in an inkjet printer. Through some Python code and shell scripts, when scanning a card, the Pi Zero is able to trigger all the Google Home compatible devices in the house to play the album selected at the same time.

It’s a visually enjoyable way to cue up some music, and likely more reliable than most voice assistants, too. We can see this being particularly useful for Weezer fans; with the band’s many self-titled releases, Siri and the Google Assistant typically fail to play the right album on request. We’ve seen other beautiful RFID jukeboxes before, but one player that really sticks out ditched the RF and just uses computer vision with vinyl albums as the ID.

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Can You Code Without Google?

February 13, 2021 by Jenny List 106 Comments

Imagine for a moment that something has taken out your phone line, cell, and fibre connection so you have no internet. For some of you this may even be reality, but go with it and imagine yourself deciding to use your unexpectedly disconnected lockdown time pursuing that code project you always promised yourself. You pull out your laptop and fire up a code editor. Can you write code that works, without the Internet as a handy crib sheet? [Austin Z. Henley] couldn’t, when he tried writing a straightforward web app. He uses it as a hook to muse on the nature of learning, and it’s certainly a thought-provoking subject.

It has become an indispensable tool for the engineer and the coder alike, to constantly refer to online knowledge. This makes absolute sense, as it provides a reference library that will be many orders of magnitude in excess of anything an individual can possibly hold personally.

This holds true whether the resource takes the form of code snippets from StackOverflow or GitHub, or data sheets from TI or Microchip. Even our calculations have moved online, as it’s often much quicker to use an online calculator on a web page to derive for example an impedance calculation. This is not necessarily a bad thing, instead it’s an enabler; skills that used to take months to master due to slow information access can now be acquired in an afternoon. But it does pose the interesting question, in the Internet age what is the measure of an expert coder? Is it the ability to produce the code effectively with whatever help is available, or is it a guru-like mastery of the code? Maybe it’s both. If you have the Internet, give us your views in the comments.

Spinach Photo Prints

February 13, 2021 by Brian McEvoy 14 Comments

Some people like spinach in their salads. Others would prefer it if it never gets near their fork. Still, other folks, like [Almudena Romero], use it for printing pictures, and they’re the folks we’ll focus on today.

Anthotypes are positive images made from plant dyes that fade from light exposure. Imagine you stain your shirt at a picnic and leave it in the sun with a fork covering part of the stain. When you come back, the stain not sheltered by cutlery is gone, but now you have a permanent fork shape logo made from aunt Bev’s BBQ sauce. The science behind this type of printmaking is beautifully covered in the video below the break. You see, some plant dyes are not suitable for light bleaching, and fewer still if you are not patient since stains like blueberry can take a month in the sun.

The video shows how to make your own plant dye, which has possibilities outside of anthotype printing. Since the dye fades in sunlight, it can be a temporary paint, or you could use samples all over your garden to find which parts get lots of sunlight since the most exposed swatches will be faded the most. Think of a low-tech UV meter with logging, but it runs on spinach.

If the science doesn’t intrigue you, the artistic possibilities are equally cool. All the pictures have a one-of-a-kind, wabi-sabi flare. You take your favorite photo, make it monochrome, print it on a transparent plastic sheet, and the ink will shield the dye and expose the rest. We just gave you a tip about finding the sunniest spot outdoors, so get staining.

Anthotype printing shares some similarities with etch-resist in circuit board printing processes, but maybe someone can remix spinach prints with laser exposure!

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Express Your Love With Candy And Engineering

February 13, 2021 by Kristina Panos 6 Comments

Still don’t have anything for Valentine’s Day? We wholeheartedly suggest that you fire up that printer and get ready to fall in love with engineering all over again, because [JBV Creative] has designed a super-sweet piece of machinery that would turn the gears of anyone’s heart. He calls this the most overly-engineered candy dispenser ever, and we have to agree. It’s certainly one of the most beautiful we’ve ever seen.

There’s no electronics at all in this elegant design, just purely mechanical, hand-cranked fun. Turning the crank does two things at once — it moves a little access panel back and forth underneath the chute that governs the number of candies given, and at the same time, moves the conveyor belt along to deliver the goods to the receiving area.

This entire design is absolute genius, especially the decoupling mechanism that shuts off the flow of candy but allows the belt to keep moving. Be sure to watch the build video where [JBV Creative] effortlessly snap-fits the machine together without a single tool, and stay for the follow-up video where he discusses the engineering challenges and shows just how much work went into it.

Of course, there’s more than one way to overly-engineer a candy dispenser. Here’s one that finds the holy grail of peanut M&Ms — the ones that didn’t get a peanut.

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Making Printed Food More Palatable For Those Who Need It

February 13, 2021 by Kristina Panos 18 Comments

Most foods when pureed become pretty unappetizing to look at. For that reason, patients who have trouble swallowing are often given pureed food that’s been molded into fun shapes to make it more appealing. The problem with molding food is that it’s labor-intensive, time-consuming, and the resulting edible toys require a lot of storage space.

When 3D printing came along, it was poised to solve the problem, but in the quest to make foods printable, they became even worse. Printable food paste typically starts with dehydrated and/or freeze-dried vegetables, and then hydrocolloids like xanthan gum and locust bean gum are added so the paste holds together after extrusion. Unfortunately, these additives are a big step backward; they change the texture for the worse, and make the food smell and taste bad, too.

The solution is one of those things that sounds obvious in hindsight: some researchers in Singapore tried using fresh and frozen foods instead of freeze-dried, and figured out the minimum amount of hydrocolloids they could get away with for a given food. In their research they categorized all the feasible foods this way. Some vegetables like garden peas which have higher starch and lower water percentages don’t need any hydrocolloids to be printable. As the starch level falls and water rises, more hydrocolloids are needed. So carrots can get away with using just one type of hydrocolloid, while things like bok choy need two types to print effectively. Even so, results of the study show that fresh vegetable printing calls for far less than their powdered counterparts to the extent that it no longer affects the taste of the end product.

The researchers envision a future where every hospital and elder care facility has a food printer to churn out carrot boats and spinach skylines on demand. We think this tasty development is totally awesome — it’s just too bad the carrot boats don’t look more like Benchy.

In the mood for printed food? Our own [Tom Nardi] sampled the menu of additive edibles a while back.

Thanks for the tantalizing tip, [Qes]!

Open Source: It’s The Little Things

February 13, 2021 by Elliot Williams 108 Comments

I use open source software almost exclusively; at least on the desktop — the phone is another matter, sadly. And I do a lot of stuff with and on computers. Folks outside of the free software scene are still a little surprised when small programs are free to use and modify, but they’re downright skeptical when it comes to the big works of professional software. It’s one thing to write xeyes, but how about something to rival Photoshop, or Altium?

Of course, we all know the answer — mostly. None of the “big” software packages work exactly the same as their closed-source counterparts, often missing a few features here and gaining a few there, or following a different workflow. That’s OK, different closed-source programs work differently as well. I’m not here to argue that GIMP is better than Photoshop, but rather to point out what I really love about open software: it caters to the little guys and gals, the niche users, and the specialists. Or rather, it lets them cater to themselves.

I just started learning FreeCAD for a CNC milling project, and it’s awesome. I’ve used Fusion 360, and although FreeCAD isn’t “the same” as Fusion 360, it has most of the features that I need. But it’s the quirky features that set it apart.

The central workflow is to pick a “workbench” where specific tasks are carried out, and then you take your part to each bench, operate on it, and then move to the next one you need. But the critical bit here is that a good number of the workbenches are contributed to the open project by people who have had particular niche needs. For me, for instance, I’ve done most of my 3D modelling for 3D printing using OpenSCAD, which is kinda niche, but also the language that underpins Thingiverse’s customizer functionality. Does Fusion 360 seamlessly import my OpenSCAD work? Nope. Does FreeCAD? Yup, because some other nerd was in my shoes.

And then I started thinking of the other big free projects. Inkscape has plugins that let you create Gcode to drive CNC mills or strange plotters. Why? Because nerds love eggbots. GIMP has plugins for every imaginable image transformation — things that 99% of graphic artists will never use, and so Adobe has no incentive to incorporate.

Open source lets you scratch your own itch, and share your solution with others. The features of for-pay, closed-source software are driven by the masses: “is this a feature that enough of our customers want?” The features of open-source software are driven by the freaky ideas of nerds just like me. Vive la différence!

Experiment With SFP Modules With This Handy Breakout

February 13, 2021 by Lewin Day 20 Comments

While most home networking hardware comes with network ports baked in from the factory, industrial grade gear is typically more versatile. Using standards like Small Form-factor Pluggable, or SFP, network switches can be used with a variety of transport mediums by simply swapping tranceivers in and out. These network devices typically handle the nitty gritty of transmitting Ethernet over fiber optics, and for those keen to experiment, this breakout may come in handy.

The board design comes complete with an SFP receptacle, allowing a variety of compatible receivers to be plugged in for experimentation. With the standard using differential signalling, the board carries hardware to allow the transceiver to be fed with single-ended signals instead, though a differential version is available too. The board can be used for transmitting different signals over fiber, outside just Ethernet, or used as a simple way to reprogram SFP modules via I2C. The latter can be useful to get around DRM in network switches that attempt to lock out generic transceiver modules.

It’s a useful piece of hardware for the fiber optic tinkerer and network admin alike. You might also find it useful if you’re building your own 10-gigabit network at home!