Trebucheting Tennis Balls At 124 MPH

September 10, 2018 by Elliot Williams 21 Comments

A trebuchet is one of the older machines of war. It’s basically a sling on a frame, with a weight that you can lift up high and which pulls the sling arm over on release. Making one opens up the doors to backyard mayhem, but optimizing one opens up the wonders of physics.

[Tom Stanton] covers just about everything you need to know about trebuchet building in his four-part video series. Indeed, he sums it up in video two: you’ve got some potential energy in the weight, and you want to transfer as much of that as possible to the ball. ~~This implies that the optimal path for the weight would be straight down, but then there’s the axle in the way.~~ The rest, as they say, is mechanical engineering.

Video three was the most interesting for us. [Tom] already had some strange arm design that intends to get the weight partially around the axle, but he’s still getting low efficiencies, so he builds a trebuchet on wheels — the classic solution. Along the way, he takes a ton of measurements with Physlets Tracker, which does video analysis to extract physical measurements. That tip alone is worth the price of admission, but when the ball tops out at 124 mph, you gotta cheer.

In video four, [Tom] plays around with the weight of the projectile and discovers that he’s putting spin on his tennis ball, making it curve in flight. Who knew?

Anyway, all four videos are embedded below. You can probably skip video one if you already know what a trebuchet is, or aren’t interested in [Tom] learning that paying extra money for a good CNC mill bit is worth it. Video two and three are must-watch trebucheting.

We’re a sad to report that we couldn’t find any good trebuchet links on Hackaday to dish up. You’re going to have to settle for a decade-old catapult post or this sweet beer-pong-playing robotic arm. You can help. Submit your trebuchet tips.

Thanks [DC] for this one!

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A DIY Balcony Crane Lifts Groceries For The Lazy But Patient

September 9, 2018 by Dan Maloney 39 Comments

If necessity is the mother of invention, then laziness is probably its father. Or at least a close uncle. Who hasn’t thought, “There has to be a better way to do this, one that doesn’t involve me burning precious calories”?

Motivational laziness seems to increase with potential energy, as anyone who needs to haul groceries up four flights of stairs will tell you. This appears to be where this balcony-mounted drill-powered crane came from. Starting with a surplus right-angle gearbox and drum, [geniusz K] fabricated the rest of the crane from steel plate and tubing. We like the quality of fabrication and the tip on making slip couplings from bits of square tubing. The finished product got a nice coat of brown paint to match the balcony railing; keeping the neighbors happy is always important. He tested the crane with a 20-kg weight before installing it on the balcony and put it to work hauling groceries up three stories. Check out the build and the test in the video below.

While it won’t set any speed records, at least the drill is doing the work. But what if you’re impatient as well as lazy? Aside from being two-thirds of the way to programming greatness, you may have to up the game. A heavy-lift quadcopter, perhaps?

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The E-Waste Apocalypse Looms

September 2, 2018 by Kristina Panos 13 Comments

What does post-apocalyptic technology look like? Well, that kind of depends on the apocalypse. Regardless of the cause, we’ll need to be clever and resourceful and re-learn ancient crafts like weaving and pottery-making. After all, the only real apocalyptic constants are the needs of the survivors. Humans need clothing and other textiles. Fortunately, weaving doesn’t require electricity—just simple mechanics, patience, and craftsmanship.

If it turns out the apocalypse is scheduled for tomorrow, we’ll have piles and piles of e-waste as fodder for new-old looms. This adorable loom is a mashup of old and new technologies that [Kati Hyyppä] built at an artist residency in Latvia, a country with a rich historical tapestry of textile-making. It combines a cheerful orange telephone with an old cassette player and some telescoping rods from a radio antenna. [Kati] reused the phone’s hang-up switch to trigger tunes from a deconstructed toddler toy every time the receiver is lifted. Check it out after the ~~beep~~ break.

And yeah, you’re right, it does use batteries. But the looming part doesn’t require power, only the music. In case of apocalypse, just scrounge up a solar panel.

If you’d rather be prepared to have to make your own clothes someday, print this loom beforehand.

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Epoxy Embedded Electronic Art Running On Pyramid Power

September 2, 2018 by Steven Dufresne 25 Comments

We sometimes get our inspirations from art. When [kodera2t] saw some Japanese art of fish drawings embedded in clear epoxy he just had to make his own. But while skilled in electronics, he wasn’t skilled at drawing. We’d still call him an artist, though, after seeing what he came up with in his electronics embedded in crystal clear epoxy.

His first works of electronic art were a couple of transistors and some ICs, including an 80386, encased in epoxy. But then he realized that he wanted the electronics to do something interesting. However, once encased in epoxy, how do you keep the electronics powered forever?

He tried a solar cell charging a battery which then powered an LED but he didn’t like the idea of chemical batteries encased in epoxy for a long time.

He then switched to wireless power transmission with a receiving coil in the base of epoxy pyramids. For one of them, the coil powers a BLE board with an attached LED which he can control from his phone. And his latest contains an ESP32-PICO with an OLED display. The code allows him to upload new firmware over the air but on his Hackaday.io page, he shows the difference between code which can brick the ESP32 versus code which won’t. But don’t take our word for it. Check out the video below to see his artistry for yourself.

While embedding electronics in epoxy is new to [kodera2t], we’ve seen it a few times before. once in the form of an amplifier circuit done beautifully, dead bug style, and a more experimental attempt with a solar lantern.

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New Mooltipass Begins Development With Call For Collaborators

August 31, 2018 by Mike Szczys 14 Comments

One of the most interesting aspects of our modern world is the ability to work collaboratively despite the challenges of geography and time zones. Distributed engineering is a trend which we’ve watched pick up steam over the years. One such example is the Mooltipass offline password keeper which was built by a distributed engineering team from all over the world. The project is back, and this time the goal is to add BLE to the mini version of the hardware. The call for collaborators was just posted on the project page so head over and check out how the collaboration works.

The key to the hardware is the use of a smartcard with proven encryption to store your passwords. Mooltipass is a secure interface between this card and a computer via USB. The new version will be a challenge as it introduces BLE for connectivity with smart phones. To help mitigate security risks, a second microcontroller is added to the existing design to act as a gatekeeper between the secure hardware and the BLE connection.

Mathieu Stephan is the driving force behind the Mooltipass project, which was one of the first projects on Hackaday.io and has been wildly successful in crowd funding and on Tindie. Mathieu and five other team members already have a proof of concept for the hardware. However, more collaborators are needed to help see all aspects of the project — hardware, firmware, and software — through to the end. This is a product, and in addition to building something awesome, the goal is to turn a profit.

How do you reconcile work on an Open Source project with a share of the spoils? Their plan is to log hours spent bringing the new Mooltipass to life and share the revenue using a site like colony.io. This is a tool built on the Ethereum blockchain to track contributions to open projects, assigning tokens that equate to value in the project. It’s an interesting approach and we’re excited to see how it takes shape.

You can catch up on the last few years of the Mooltipass adventure my checking out Mathieu’s talk during the 2017 Hackaday Superconference. If this article has you as excited about distributed engineer as we are, you need to check out the crew that’s building this year’s Open Hardware Summit badge!

Perf Board Pyrotechnics Courtesy Of A High-Voltage Supply

August 26, 2018 by Dan Maloney 21 Comments

You may have asked yourself at one time or another, “Self, what happens when you pass 100 thousand volts through a printed circuit board?” It’s a good question, and [styropyro] put together this fascinating bit of destructive testing to find out.

Luckily, [styropyro] is well-positioned to explore the high-voltage realm. His YouTube stock-in-trade is lasers, ranging from a ridiculously overpowered diode-laser bazooka to a bottle-busting ruby laser. The latter requires high voltage, of course, and his Frankenstein’s lab yielded the necessary components for this destructive diversion. A chopper drives dual automotive ignition coils to step the voltage up to a respectable 100 kV. The arcs across an air gap are impressive enough, but when applied to a big piece of copper-clad protoboard, the light show is amazing. The arcs take a seemingly different path across the board for each discharge, lighting up the path with an eerie blue glow accompanied by a menacing buzz. Each discharge path may be random, but they all are composed of long stretches across the rows and columns of copper pads that never take the more direct diagonal path. [styropyro]’s explanation of the math governing this behavior is feasible, but really we just liked looking at the pretty and dangerous display. Now if only the board had been populated with components…

No, there’s not much of a hack here, but it’s cool nonetheless. And it’s probably a well-earned distraction from his more serious stuff, like his recent thorough debunking of the “Chinese laser rifle” that was all over the news a while back.

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Two Bit Circus Took The Tech We Love And Built An Amusement Park

August 24, 2018 by Roger Cheng 5 Comments

Carnival games are simple to pick up, designed to provide a little bit of entertainment in exchange for your game ticket. Given that the main point is just to have some silly fun with your friends, most game vendors have little reason to innovate. But we are people who play with microcontrollers and gratuitous LEDs. We look at these games and imagine bringing them into the 21st century. Well, there’s good news: the people of Two Bit Circus have been working along these lines, and they’re getting ready to invite the whole world to come and play with them.

“Interactive Entertainment” is how Two Bit Circus describe what they do, by employing the kinds of technology that frequent pages of Hackaday. But while we love hacks for their own sake here, Two Bit Circus applies them to amuse and engage everyone regardless of their technical knowledge. For the past few years they’ve been building on behalf of others for events like trade shows and private parties. Then they worked to put together their own event, a STEAM Carnival to spread love of technology, art, and fun. The problem? They are only temporary and for a limited audience, hence the desire for a permanent facility open to the public. Your Hackaday scribe had the opportunity to take a peek as they were putting on the finishing touches.

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