3D Printed Dogbox Transmission Kicks Your Desk Into High Gear

March 20, 2020 by Tom Nardi 9 Comments

It’s often been our experience that some of the most impressive projects are the passion builds, the ones where the builder really put in their all and obsessed over every detail. Even if they don’t always have a practical application, it’s impossible to look at the final product and not respect the accomplishment.

Case in point, this absolutely incredible 3D printed model of a sequential “dogbox” transmission created by [Indeterminate Design]. All of the STL files and a complete bill of materials are available for anyone brave enough to take on the challenge. It might never be mounted to a vehicle and driven around the track, but you can still flick through the gears and watch the complex gearing do its thing.

Even if you don’t want to necessarily build the model itself, [Indeterminate Design] takes you through the concepts behind this unique transmission and how it differs from the sort of gearboxes us lowly commuter drivers are familiar with. He’s even nice enough to explain what a dogbox is.

Put simply, this type of transmission allows the driver to simply move the gear change forward and backwards to step through the gears like in a video game. This prevents you from having to navigate an H-pattern gear shift while dealing with all the other stresses of competition driving. Watching it in action, you can certainly see the appeal.

If you prefer your printed gearboxes to be of the practical variety, we’ve certainly seen plenty of those as well. They’re perfect for next time you need to move an anvil around the shop.

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Prusa Advises On Printed Medical Devices, Releases Face Shield

March 20, 2020 by Tom Nardi 37 Comments

Like everyone else, hackers and makers want to do something to help control the spread of COVID-19. The recent posts on Hackaday dealing with DIY and open source approaches to respirators, ventilators, and masks have been some of the most widely read and commented on in recent memory. But it’s important to remember that the majority of us aren’t medical professionals, and that even the most well-meaning efforts can end up making things worse if they aren’t done correctly.

Which is exactly what [Josef Průša] wanted to make clear about 3D printed medical equipment in his latest blog post. Like us, he’s thrilled to see all the energy the maker community is putting into brainstorming ways we can put our unique skills and capabilities to use during this global pandemic, but he also urged caution. Printing out an untested design in a material that was never intended for this sort of application could end up being more dangerous than doing nothing at all.

The nested design lends itself to mass production.

To say that he and his team are authorities in the realm of fused deposition modeling (FDM) would be something of an understatement. They know better than most what the technology is and is not capable of, and they’re of the opinion that using printed parts in respirators and other breathing devices isn’t viable until more research and testing is done

For example, how can we ensure the porous plastic parts are sterilized and not just serving as a breeding ground for bacteria? It’s hardly a new concern; the debate about printed objects in food contact applications has been going on for years.

The safest option is to only use printed parts for structural components that don’t need to be sterile. To that end, [Josef] used the post to announce a newly published design of a printable face shield for medical professionals. Starting with an existing open source design, the Prusa Research team used their experience to optimize the headband for faster and easier printing. They can produce four headbands at once on each of the printers in their farm, which will allow them to make as many as 800 shields per day without impacting their normal business operations. The bottleneck on production is actually how quickly they can cut out the clear visors with their in-house laser, not the time it takes to print the frames.

It’s easy to get excited when success stories featuring 3D printed medical devices are in the news, but that doesn’t mean you should be cranking out lifesaving devices with that roll of bargain PLA you’ve had sitting around the shop. As difficult as it may be for some of us to admit, the safest thing might be to let our spare CPU cycles do battle with COVID-19 instead.

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An Armored Vehicle From Foam Core And Big Box Toys

March 19, 2020 by Tom Nardi 7 Comments

Over the last several months, [Eric Strebel] has been working on a concept for an electric-powered infantry combat vehicle. We don’t think he’s been contracted by any nation’s military to design this vehicle, but as a product designer we imagine he does this sort of thing to keep himself sharp. In any event, it’s been fun to watch from the sidelines.

In the latest installment in this series of videos, [Eric] turns his earlier concept art into a functional prototype; albeit at somewhat reduced scale. Still, building any kind of vehicle from the ground up is no easy feat and it’s fascinating to watch the process.

The futuristic faceted look of the vehicle’s armor plate makes for an exceptionally time-consuming build, as he has to cut and glue each piece of foam core into place. Some of the smaller pieces seem to have the tell-tale char marks from a trip through the laser cutter, but in the video after the break you can see that the larger panels are hand cut with a razor.

The plan was originally to just make a static mock-up of the vehicle, but thanks to a pair of remote controlled trucks that [Eric] found at this local Big Box retailer, this foam fighter ended up getting an upgrade. After liberating the motors and gearboxes from the two trucks, he 3D printed axle extensions to take into account the wider track of his vehicle, and built his “tub” around it. While the R/C gear is clearly on the low end of the spectrum, the overall effect looks great as the vehicle is bounding around the yard.

Readers of Hackaday will no doubt be well aware of [Eric Strebel] and his many talents. From 3D scanning via photogrammetry to embedding electronics into flexible molded parts, you’re sure to learn something new from following this prolific maker.

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You’ll Flip For This Toggle Switch Handheld Game

March 18, 2020 by Tom Nardi 13 Comments

Teacher says that every time a toggle switch clunks, a hacker gets their wings. Or something like that. All we know is that there are few things the hardware tinkerer likes more than the satisfying action of a nice flip. Which by extension means this handheld game built by [Roman Revzin] and controlled by nothing more than three toggle switches will likely be a big hit at the hackerspace.

The parts list for this game, which [Roman] calls the ToggleBoss, is about as short as it gets. There’s a NodeMCU ESP8266 development board, a common SH1106 OLED display, and a trio of suitably clunky toggle switches. Add a bit of wire, toss it all into a 3D printed enclosure, and you’re halfway to thumb flicking nirvana.

Naturally, you might be wondering about the sort of games that can be played with three latching digital inputs; after all, it’s not exactly the most conventional controller layout. But there is where ToggleBoss really shines. Instead of trying to shoehorn traditional games into an exceptionally unconventional system, [Roman] has come up with several games which really embrace the limited input offered to the user.

In a platforming game not unlike the classic Mario Bros, the positions of the physical switches are mapped to virtual walls that are raised and lowered to control a character’s movement through the level. Another game shows the player three dots which correspond to the intended switch states, which they have to match as quickly and as accurately as possible. [Roman] has released the source code to his current lineup of games, which hopefully will inspire others to try their hand at creating software for this fascinating little system.

With the availability of cheap OLED displays and powerful microcontrollers, we’ve started to see more of these bespoke gaming systems. While some will undoubtedly prefer a pocket full of Nintendo’s classics, we think there’s something special about a game system that you can truly call your own.

Teardown: Cobra XRS 9740 Radar Detector

March 18, 2020 by Tom Nardi 46 Comments

Drivers with a lead foot more often than not have Waze open on their phone so they can see if other drivers have spotted cops up ahead. But avoiding a speeding ticket used to involve a lot more hardware than software. Back before the smartphone revolution, that same driver would have had a radar detector on their dashboard. That’s not to say the gadgets are completely unused today, but between their relatively high cost (one of the top rated models on Amazon as of this writing costs over $300) and the inevitable false positives from so many vehicles on the road having their own radar and LIDAR systems, they’ve certainly become a less common sight over the years

The subject of today’s teardown is a perfect example of “Peak Radar Detector”. Manufactured back in 2007, the Cobra XRS 9740 would have been a fairly mid-range entry offering the sort of features that would have been desirable at the time. Over a decade ago, having an alphanumeric display, voice alerts, and a digital compass were all things worth shouting about on the box the thing was sold in. Though looking like some kind of Cardassian warship was apparently just an added bonus.

As the name implies these devices are primarily for detecting radar activity, but by this point they’d also been expanded to pick up infrared lasers and the strobe beacons on emergency vehicles. But false positives were always a problem, so the device allows the user to select which signals it should be on the lookout for. If you were getting some kind of interference that convinced the detector it was being bombarded with IR lasers, you could just turn that function off without having to pull the plug entirely.

But it’s important to remember that this device was built back when people were still unironically carrying around flip phones. Detecting laser and multi-band radars might sound like something pulled from the spec sheet of a stealth fighter jet, but this is still a piece of consumer electronics from more than a decade in the past. So let’s crack it open and take a look at what goes on inside a radar detector that’s only a few years away from being old enough to get its own driver’s license.

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Hearing Plants Giggle Is Just As Creepy As You Think

March 18, 2020 by Tom Nardi 13 Comments

While best known for Charlie and the Chocolate Factory, Roald Dahl wrote quite a few similarly oddball stories in his time. One of them, The Sound Machine, is about a device that allowed the user to hear the anguished screams of trees as they were cut down. Sounds kind of weird to us, but [Roni Bandini] liked the idea so much he decided to build his own version.

Now to be fair, the device doesn’t only scream in pain. In fact, most of the time it should be emitting laughs and happy noises. Using a moisture sensor driven into the soil of a plant’s pot, the device uses these audio cues to tell you the relative health of your leafy friend. So assuming you’ve got any sort of green thumb at all, things should be fine.

But once the soil gets too dry and the device determines the plant is in “pain”, things take a turn for the worse. We suppose it doesn’t technically scream out so much as grunt like a zombie, but it’s still not a noise we’d want to hear while walking through the house at night. Luckily, it seems you need to hit the button on the front of the 3D printed enclosure to get it to play the appropriate sound track from its DFPlayer module.

Personally we’d rather build something that makes sure the plants are being taken care of automatically than a gadget that cries out in anguish to remind us that we don’t know what we’re doing. But hey, everyone gets inspired in their own way.

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A Smart Controller For Your DIY UV Cure Box

March 17, 2020 by Tom Nardi No comments

Resin 3D printers are finally cheap enough that peons like us can finally buy them without skipping too many meals, and what means we’re starting to see more and more of them in the hands of hackers. But to get good results you’ll also want a machine to cure the prints with UV light; an added expense compared to more traditional FDM printers. Of course you could always build one yourself to try and save some money.

An earlier prototype build of the interface.

To that end, [sjm4306] is working on a very impressive controller for all your homebrew UV curing needs. The device is designed to work with cheap UV strip lights that can easily be sourced online, and all you need to bring to the table is a suitable enclosure to install them in. Here he’s using a metal paint can with a lid to keep from burning his eyes out, but we imagine the good readers of Hackaday could come up with something slightly more substantial while still taking the necessary precautions to not cook the only set of eyes you’ll ever have.

Of course, the enclosure isn’t what this project is really about. The focus here is on a general purpose controller, and it looks like [sjm4306] has really gone the extra mile with this one. Using a common OLED display module, the controller provides a very concise and professional graphical user interface for setting parameters such as light intensity and cure time. While the part is cooking, there’s even a nice little progress bar which makes it easy to see how much time is left even if you’re across the room.

At this point we’ve seen a number of hacked together UV cure boxes, but many of them skip the controller and just run the lights full time. That’s fine for a quick and dirty build, but we think a controller like this one could help turn a simple hack into a proper tool.

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