Cat Feeder Depends On RFID To Keep The Peace At Dinnertime

February 28, 2023 by 10 Comments

Anyone with more than one cat can tell you that the joy mischief they bring into your life is much more than twice that of a single cat. And if those felines have different dietary needs, you can end up where [Benjamin Krejci] found himself, which resulted in this fancy RFID cat feeder.

For a little backstory, [Ben]’s furry friends [Luna] and [Fermi] have vastly different eating styles, with the former being a grazer and the latter more of a “disordered eater,” to put it politely. [Fermi] tends to eat until she vomits, which is fun, and muscles her pickier sister away from the bowl if there’s anything left in it. [Ben]’s idea was to leverage [Luna]’s existing RFID chip, which he figured would be a breeze. But the vet-inserted chip is designed to be read by a high-power reader directly in contact with the cat’s skin, which made reliably reading the chip a challenge.

Several round of design iteration resulted in the current configuration, with a large antenna coil poised above and behind the food dispenser. [Luna] has no choice but to put the back of her neck and shoulder blades almost directly in contact with the coil, which makes it easier to read the 134.2-kHz chip with a long-distance RFID module. If [Luna]’s chip is found, the lid on the food bowl opens gently and quietly, so as not to spook the mild-mannered cat. The lid stays open as long as [Luna] is in place thanks to some IR sensors, but as soon as she backs out, the lid comes down to keep [Fermi] from gorging herself.

Hats off to [Ben] for working through the problem and coming up with what looks like a fine solution. We suppose he could have tried something easier like weighing the two cats to distinguish between them, but this seems like a cleaner solution to us.

When One Cylinder Isn’t Enough: The Briggs And Stratton V8

February 28, 2023 by 13 Comments

The Briggs & Stratton single cylinder sidevalve engine is one that has been in production in one form or another for over a century, and which remains one of the simplest, most reliable, and easiest to maintain internal combustion engines there is. The little single-cylinder can be found on lawnmowers and other similar machinery everywhere, so it’s rather easy to find yourself in possession of more than one. [Lyckebo Mekaniska] evidently had no shortage of them, because he’s produced a V8 engine for a small lawn tractor using eight of them. A small air-cooled V8 sidevalve is something of a unique engine to be made in the 2020s, and the series of videos is definitely worth a watch from start to finish. We’ve been keeping an eye on this build for a while now, and we’ve embedded it below the break for your entertainment.

A CAD view of the V8 engine
Clearly a lot of CAD work has gone into this build.

For an engine which uses mass-produced engines for its construction, this one still relies heavily on parts machined from first principles. The cylinder blocks, valves, pistons, and crank rods are Briggs & Stratton, the rest is made in the workshop. It’s a design with the valves on the outside — so instead of the single camshaft you might expect from experience with OHV engines nestling in the V above the camshaft it has two camshafts at the bottom of the crankcase.

The crankcase is cast in sections first, followed by the machining of the crankshaft and camshafts, then the preparation of the cylinders.. The engine is assembled with a home made alternator on its flywheel and a conventional distributor from a donor vehicle. The lubrication system is another work of the machinist’s art, and the simple straight-through exhaust system is more at home on a drag racer than a lawnmower. Finally we see it running, and it sounds the business. Most recently he’s had to deal with a seizure and a replacement cylinder, but now it’s back together and he’s working on an improved cooling system.

All in all this is one heck of a build, and we wish we had some of those skills. We’re not sure whether he’ll mow the lawn with this thing, but one thing’s for sure, lawnmower hacking has quite a past.

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Supercon 2022: Selling Your Company And Not Your Soul

February 28, 2023 by 11 Comments

Haddington Dynamics is a particular company. After winning the 2018 Hackaday Prize with an open-source robotic arm, we’ve covered their micro-factories and suction cup end-effectors for making face shields during 2020. They’ve been laser-focused on their mission of creating a fantastic robot arm at a small price tag with open-source software and design. So how does a company with such a hacker ethos get bought by a much larger company, and why? They came to SuperCon 2022 to share their story in a panel discussion.

Haddington Dynamics started with two clever inventions: optical encoders that used analog values instead of digital values and an FPGA that allowed them to poll those encoders and respond rapidly. This allowed them to use cheaper motors and rely on the incredibly sensitive encoders to position them. After the Hackaday prize, they open-sourced the HD version of the robot and released the HDI version. But in 2020, they were bought by a group called Ocado. As to why the somewhat practical but not exciting answer is that they needed money. Employees needed to be paid, and they needed capital to keep the doors open.

So this leads to the next tricky question, how do you sell your company without changing it? The fine folks at Haddington Dynamics point out in their panel discussion that a company is a collection of people. The soul of that company is the collective soul of those people coming together. A company being bought can be akin to stopping working for yourself and going to work for someone else. Working alone, you have values and principles that you can easily stick to. But once you start working for someone else, they will value different things, and while the people that make up the company might not change, the company’s decisions might become unrecognizable.

As the panel points out, looking for a buyer with the same values is critical. Ocado was a great fit as their economic interests and culture matched Haddington’s. However, it’s not all roses, as Ocadao tends to be a very closed-source group. However, Haddington Dynamics still supports its open-source initiatives. It’s a fascinating look into a company’s life cycle and how they navigate the waters of open-source, funding, acquisitions, innovation, and invention. Despite the fairytale-like nature of inventing a revolutionary robot arm in your garage and winning many awards, it turns out there is quite a lot that happens after the happily ever after.

We look forward to seeing more of Haddington Dynamics and where they go next. Video after the break.

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A series of five cymbals sitting on white and black speckled carpet in front of a green loveseat. Each cymbal is assembled from four printed sections. Their colors from left to right are yellow and grey, red and black, black, teal and black, and white and black. A sixth, grey and black cymbal is sitting in the middle of the loveseat cushion.

Challenging The Limits Of 3D Printing With Cymbals

February 28, 2023 by 22 Comments

We’re big believers in 3D printing here at Hackaday, but it’s important to recognize that there are plenty of applications where additive manufacturing (at least, from a desktop machine) just isn’t suitable. But that doesn’t mean we don’t want to see what happens if you try. For example, [The Drum Thing] wanted to test the limits of 3D printing by printing a set of cymbals.

[The Drum Thing] had a friend design a cymbal in CAD and then the printed quarters were glued together. In the name of science, they produced them in six different materials to compare performance. Each cymbal was played for a short period or until it failed, including some very interesting slow motion camera work showing the vibrations traveling through the cymbals.

As one might expect, bashing “wafer thin” pieces of printed plastic with a wooden drumstick didn’t work out well for most of the cymbals, although the TPU, carbon fiber, and nylon cymbals were did largely survive their time in the limelight. The other cymbals all failed, either shattering, cracking, or failing at the glue joints. Based on the video, it seems the same glue was used for all of the cymbals, so making sure to have a better match between material and adhesive could help with the glue failures.

Maybe future testing can involve playing these cymbals with a quadrotor?

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Repurposing Old Smartphones: When Reusing Makes More Sense Than Recycling

February 28, 2023 by 89 Comments

When looking at the specifications of smartphones that have been released over the past years, it’s remarkable to see how aspects like CPU cores, clockspeeds and GPU performance have improved during this time, with even new budget smartphones offering a lot of computing power, as well as a smattering of sensors. Perhaps even more remarkable is that of the approximately 1.5 billion smartphones sold each year, many will be discarded again after a mere two years of use. This seems rather wasteful, and a recent paper by Jennifer Switzer and colleagues proposes that a so-called Computational Carbon Intensity (CCI) metric should be used to determine when it makes more sense to recycle a device than to keep using it.

What complicates the decision of when it makes more sense to reuse than recycle is that there are many ways to define when a device is no longer ‘fit for purpose’. It could be argued that the average smartphone is still more than good enough after two years to be continued as a smartphone for another few years at least, or at least until the manufacturer stops supplying updates. Beyond the use as a smartphone, they’re still devices with a screen, WiFi connection and a capable processor, which should make it suitable for a myriad of roles.

Unfortunately, as we have seen with the disaster that was Samsung’s ‘upcycling’ concept a few years ago, or Google’s defunct Project Ara, as promising as the whole idea of ‘reuse, upcycle, recycle’ sounds, establishing an industry standard here is frustratingly complicated. Worse, over the years smartphones have become ever more sealed-up, glued-together devices that complicate the ‘reuse’ narrative.

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Collection Of Old Films Rescued For Preservation

February 28, 2023 by 31 Comments

Periscope Film owners [Doug] and [Nick] just released a mini-documentary about the rescue of a large collection of old 35 and 16 mm celluloid films from the landfill. The video shows the process of the films being collected from the donor and then being sorted and organized in a temporary storage warehouse. There is a dizzying variety of films in this haul, from different countries, in both color and black and white.

We can see in the video that their rented 8 meter (26 foot) cargo truck wasn’t enough to contain the trove, so they dragged along a 1.8 x 3.6 m (6 x 12 ft) double-axle trailer as well. That makes a grand total of 49 cubic meters of space. Our back-of-the-envelope calculations says that filled to the brim, that would be over 30,000 canisters of 600 m (2,000 ft) 35 mm movie reels.

When it comes to preserving these old films, one big problem is physical deterioration of the film stock itself. You will know something is wrong when you get a strong acetic or vinegary odor when opening the can. [Nick] shows some examples where the film has even become solidified, taken on a hexagonal shape. It will take months to just assess and catalog the contents of this collection, with damaged films that are still salvageable jumping to the head of the queue to be digitized.

Film Scanning Artist [Esteban] Performing Color Correction
Films are digitized at 4K resolution using a Lasergraphics ScanStation archival quality film scanning system, and then the restoration fun begins. One issue demonstrated in this video is color deterioration. In the Eastmancolor film technology introduced in the 1950s, the blue dyes deteriorate over time. This, and a plethora of other issues, are corrected in the restoration process.

We’re particularly jealous of film scanning artist [Esteban]’s triple-headed trackball. We learned from a quick Google search this beast is merely the entry level control panel from UK company Tangent — they make even larger flavors.

If you’re interested in doing this with 8 mm home movies, we covered a project way back in 2011 of a DIY home movie scanning project. We also covered one of Periscope Film’s restored training films about NASA soldering techniques from 1958. Kudos to organizations who focus on keeping these types of interesting and historical films from being dumped in the landfill and lost forever.

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Move Over Steel, Carbon-Reinforced Concrete Is Here

February 28, 2023 by 62 Comments

Reinforced concrete is the miracle material which made possible so many of the twentieth century’s most iconic structures, but here in this century its environmental footprint makes it something of a concern. As part of addressing this problem, a team at TU Dresden in Germany have completed what is believed to be the world’s first building made with carbon-reinforced concrete, in which the steel rebar is replaced with carbon fiber.

New materials are always of interest here at Hackaday, so it’s worth reading further about the nature of the reinforcement. The carbon fiber is woven into a mesh, or as a composite material that mimics existing rebar structures. These two types of reinforcement can be combined in a composite to produce a concrete structure much lighter than traditional steel-reinforced ones. If you page through the architecture critic description, it’s this lightness which has enabled the curving structure of the Dresden building to be so relatively thin.

The carbon saving comes presumably in the lower energy cost from not smelting iron to make steel, as well as the need for less concrete due to the lightness. All we need now is a low-carbon replacement for Portland cement.

Want to know more about concrete reinforcement? We’ve got you covered.