Brass screen is soldered together into a large mold for cardboard pulp.

How To Make A Classy, Brassy Cardboard Pulp Mold

November 17, 2021 by Kristina Panos 4 Comments

When we last checked in with prolific prototypist [Eric Strebel], he was perfecting the design of an eco-friendly wireless charger and turning his initial paper prototype into a chipboard version 2.0 that takes manufacturing concerns into consideration. At the end of this second video in a series, [Eric] was printing out the early versions of the form by which he would eventually make a brass screen mold for working with cardboard pulp. You know, the stuff that some egg cartons are made from.

In the video below, it’s time to build the pulp mold by creating three smaller molds and then joining them into one horizontal mold. The result is a single piece that then gets folded up into a charging stand, much like the egg carton. [Eric] is using brass screen here, but says that copper would be a good choice, too.

After cutting the brass with scissors and pounding them flat, he uses the 3D-printed molds from the previous video to press them into the correct shapes. Each of the three pieces needs a frame, which [Eric] makes from more brass screen, then stitches it to the mold piece with loose screen threads before securing the unions with solder.

Since the weight of all the water would likely bend the brass out of shape, [Eric] finished off the mold by soldering on a frame of flat brass strip. Check out this awesome process below, and stay tuned for the next video when [Eric] pulps some cardboard and pumps out some eco-friendly chargers.

Does this look too complicated? You could always skip the whole mesh mold thing and shape your cardboard confetti directly into 3D printed parts.

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Chipboard prototype of a wireless phone charger with style.

Prototyping Your Way To Better Prototypes

November 13, 2021 by Kristina Panos 13 Comments

If you’ve ever made a prototype of something before making the “real” one or even the final prototype, you probably already know that hands-on design time can’t be beat. There’s really no substitute for the insight you will glean from having a three-dimensional thing to hold and turn over in your hands for a full assessment. Sometimes you need to prototype an object more than once before investing time, money, and materials into making the final prototype for presentation.

This is [Eric Strebel]’s second video in series about making an eco-friendly wireless phone charger. He made a paper prototype in the first video, and in this follow-up, he refines the idea further and makes a chipboard version of the charger before the final molded paper pulp prototype. The main advantage of the chipboard version is to design the parts so that each one will be easier to pull from its mold in a single piece without any undercuts.

By building the chipboard version first, [Eric] is able to better understand the manufacturing and assembly needs of this particular widget. This way, he can work out the kinks before spending a bunch of time in CAD to create a 3D-printed mold and making the paper pulp prototype itself. He emphasizes that this process is quite different from the 2.5D method of laser-cutting a single piece of chipboard and folding it up into a 3D object like it was a cereal box, which is likely to hide design issues. Be sure to check out the video after the break.

We think this prototype is quite nice-looking, and believe that everything deserves good design. Why should a wireless charger be any different? [Eric] has prototyped in a lot of media, but he seems especially skilled in the art of foam core board. Start with the masterclass and you’ll have a better appreciation for his foam armored vehicle and one of the many ways he smooths out foam parts.

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Build Your Own HV Capacitors

November 11, 2021 by Al Williams 28 Comments

Finding high voltage capacitors can be tricky. Sure, you can buy these capacitors, but they are often expensive and hard to find exactly what you want. [RachelAnne] needed some low-value variable capacitors that would work at 100 kV. So she made some.

Instead of fabricating the plates directly, these capacitors use laminations from a scrap power transformer. These usually have two types of plates, one of which looks like a letter “E” and the other just like a straight bar. For dielectric, the capacitors use common transparency film.

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A functioning model of the Wunderwaffe DG-2 from Call of Duty: Zombies.

DIY Wunderwaffe And Others Make Up This Open-Source Arsenal

November 7, 2021 by Kristina Panos 17 Comments

Unless you stay up all night and have a dozen printers going, it’s probably way too late to make one of these beautiful prop weapons designed by [Andrew] of The Ray Gun Project in time for Halloween. Most of them are from Call of Duty: Zombies, though there is an awesome little disco grenade from Fortnite as well.

All of the projects are fantastic, but we chose to highlight the Wunderwaffe DG-2 from COD: Zombies because, well, vacuum tubes. For those unfamiliar with the ‘waffe’s operation, those vacuum tubes act as ammo magazines. Once they’re empty, you power them down with that big red switch and eject them one at a time with the lever, just like in the game.

Inside is a Feather M0 Express that runs the RGB LEDs and uses a Hall effect sensor to read magnets in the quick-change ammo magazine. You can see how it works in the demo video after the break.

There are BOMs for several of the prop weapons, along with assembly drawings and support forums for anyone who wants to build their own. Don’t feel like gathering all the bits and bobs yourself? [Andrew] is selling hardware packs for the ray gun, but you’ll have to scrounge the parts yourself if you want to build the Wunderwaffle.

Are you a Grinch who wants to keep kids off of your lawn? Scare ’em off with a giant NERF gun.

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Pulp-Molding: A Use For Cardboard Confetti

November 5, 2021 by Kristina Panos 21 Comments

We’re pretty sure that we don’t have to tell you how great cardboard is. You probably sing the praises yourself and use it for everything from a work surface protective layer to a prototype of your next amazing build. But if you still find yourself flush with cardboard even after all that, here’s one thing you can do with all those pieces that are too small to use for anything else– chuck them in an old blender, whip up some cardboard pulp, and press that gunk into some 3D-printed molds.

In addition to a step-by-step of the process, [flowalistik] offers a mold set of STL files for various useful items like a pencil holder, a box with a lid, a tray, and a coaster, as well as the Fusion 360 files in case you want to change them around. You might want to seal the coaster with something protective so that it doesn’t mold/disintegrate/bloom from condensation.

Each part consists of the walls, the wall clip that keeps them closed, but allows for de-molding and reuse, the bottom lid, and the top lid. All these prints need to be pretty high-res so that they can withstand the pressure of the clamp holding it all together. [flowalistik] recommends a layer height no larger than .03mm and a 20% infill.

The process of making the pulp itself is fairly simple, and the recipe only calls for water and some kind of binder. To start, remove all tape, coatings, staples, and anything else non-soluble from the cardboard. Cut it into bite-sized pieces your blender will enjoy, and add water and PVA glue or rice paste. Mix it up, remove the excess water by squeezing your pulp inside of a piece of cloth, and then use it to fill up your mold. You’ll want to press out the water as you go and fill it further, then finally apply the clamp. You can start de-molding parts on a schedule, starting with the clamp after about six hours. Once it’s fully dried in about two days, you can treat it like MDF and sand, cut, or even drill it. We think some of these would look pretty good with a coat of paint.

Need your objects to be more sturdy? Keep that printer warmed up — you can use prints to cast concrete, too.

There’s Not A Cassingle Thing Missing From This Cassette Deck Masterclass

October 26, 2021 by Kristina Panos 78 Comments

For [ke4mcl], this whole cassette craze of late is not a new discovery so much as it is a personal nostalgia machine. Since [ke4mcl] sees a lot of basic questions go unanswered, they made an incredible beginner’s guide to all things cassette deck. This concise wealth of information covers everything from terminology to operation, basic maintenance like repairing the belt and lubricating the motor, and appropriate cleaning methods for the various parts. Yep, we’re pretty sure this covers everything but the pencil winding technique, which you probably already knew about.

You don’t need a lot of tools and supplies to maintain a cassette deck or twelve (apparently they’re addictive) — mostly just head cleaning fluid, isopropyl, window cleaner, and a bunch of cotton swabs. And given this guide, you’ll enter the enclosure confidently, armed with knowledge about everything from the belts to the capstan to the head. This is valuable information, the kind of stuff your older brother wouldn’t take the time to explain to you in the 80s. But maybe he didn’t know reverse bias from the holes in the top of the tape.

Don’t care for the quality of audio cassettes? Tapes are good for lots of stuff, like data storage and decoration.

IoT flower pot monitors moisture and temperature levels.

Smart Flower Pot Build Is All About That Base

October 26, 2021 by Kristina Panos 10 Comments

For some reason, it seems like most of the plant monitoring setups we see separate the plant and the monitoring system. This makes sense in a don’t-own-a-waterbed-and-a-cat kind of way, but it also doesn’t from an aestheitc standpoint. This build by [Jorge Enrique Gamboa Fuentes] sure does look nice and tidy as an all-in-one unit, and fortunately is built with obvious issues in mind. It tracks water level, soil moisture, and soil temperature with a single device — a STEMMA-connected soil sensor that does all the monitoring work.

This attractive beginner build is a Python-powered project that runs on a PyPortal Titano and has a speaker that anthropomorphizes the thing so it can ~~berate you~~ politely ask for water in English. But the real magic of this build is in the enclosure itself. Thankfully, it’s designed with a drip tray, but it also keeps the electronics out of the water, allowing just the tip of the sensor to get wet. You can view the vital signs directly on the device, or on a web dashboard whenever you’re away.

In the future, [Jorge] wants to experiment with GCP and Azure, connect more flower pots together, and add more sensors so that it is more autonomous. One of the major lessons learned was that you probably shouldn’t start with a succulent, because they need very little water and this will drag out your development time considerably unless you over-water it, which will kill it. Check it out after the break.

If [Jorge] wanted to go the easy route, they might stick this plant under an old Keurig that’s been converted to an automatic watering device.

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