Hands On With Variable Layer Height

3D printers are an exercise in compromise. Generally, you don’t want a lot of mass on your tool head, as that can lead to ringing and other mechanical artifacts on your print. However, direct drive extruders are better for many filaments, and the decision on what printer to build ultimately comes down to a choice between speed, build area, and the ability to print in exotic filaments.

Even in slicing a 3D model, a 3D printing enthusiast must balance the quality of a print versus how long the print will take to squirt out of a nozzle. Now, just about any printer can produce fantastic models at a very high layer height, but no one wants to wait several days for the print to finish.

This balance between print time and print quality has, for the last few years, been completely ignored. One of the best solutions to this we’ve seen is variable layer height slicing. Basically, if you’re printing something without much detail, you don’t need small layers in your 3D print. Think of it as printing the neck of a bust at 0.3mm layer height, and the face at 0.1mm.

Yes, there were a few papers from a decade ago laying the conceptual foundations of variable layer height slicing. 3D printers weren’t exactly common back then, though. Recently, Autodesk’s Integrated Additive Manufacturing Team released Varislice for automatic generation of variable layer heights on a 3D printed object. So far, though, there’s no good automated solution for variable layer height slicing, and the tools for manual configuration of variable layer height slicing are terrible.

For the past few months, Prusa Research has been working on their own edition of Slic3r that includes an easy to use interface for variable layer height slicing. This version of Slic3r was just released, and now it’s time for the hands-on. Does variable layer height slicing work?

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Building Homebrew VTOL Rockets

No one can deny what SpaceX and Blue Origin are doing is a feat of technological wizardry. Building a rocket that takes off vertically, goes into space, and lands back on the pad is an astonishing technical achievement that is literally rocket science. However, both SpaceX and Blue Origin have a few things going for them. They have money, first of all. They’re building big rockets, so there’s a nice mass to thrust cube law efficiency bump. They’re using liquid fueled engines that can be throttled.

[Joe Barnard] isn’t working with the same constraints SpaceX and Blue Origin have. He’s still building a rocket that can take off and land vertically, but he’s doing it the hard way. He’s building VTOL model rockets. Most of the parts are 3D printed. And he’s using solid motors you can buy at a hobby shop. This is the hard way of doing things, and [Joe] is seeing some limited success with his designs.

While the rockets coming out of Barnard Propulsion Systems look like models of SpaceX’s test vehicles, there’s a lot more here than looks. [Joe] is using a thrust vectoring system — basically mounting the Estes motor in a gimbal attached to a pair of servos. This allows the rockets to fly straight up without fins or even the launch rod used to get the rocket up to speed in the first few millseconds of flight. This is active stabilization of a model rocket, with the inevitable comments of ITAR violations following soon afterward.

Taking off vertically is one thing, but [Joe] is also trying to land his rockets vertically. Each rocket he’s built has a second Estes motor used only for landing. During descent, the onboard microcontroller calculates the speed, altitude, and determines if it’s safe to attempt a vertical landing. If the second motor has sufficient impulse to make velocity and altitude equal zero at the same time, the landing legs deploy and the rocket hopefully makes a soft touchdown in the grass.

While [Joe] hasn’t quite managed to pull off a vertical takeoff and landing with black powder motors quite yet, he’s documenting and livestreaming all of his attempts. You can check out the latest one from a week ago below.

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SparkFun Gets Back To Their Roots With SparkX

Way back in the before years when there were still interesting concepts for reality TV, Nate Seidle blew up a power supply in his dorm room. Instead of finding replacement parts, Nate decided to start a company. For the last decade and a half, SparkFun has grown immensely, been an incredible resource for makers and engineers alike, and shipped out hundreds of thousands of their iconic red boxes.

Being the CEO of a company means you need to do CEO stuff, and a few summers ago Nate the CEO became Nate the Engineer once again. SparkFun is still doing great, but now we know what Nate has been up to these last months. He’s getting back to SparkFun’s roots with SparkX. This is the newest stuff SparkFun has to offer, there is zero documentation or support, and they’re only developing products because Nate wants to.

In a series of blog posts on the SparkFun blog, Nate goes over what is involved in building a new brand for the latest and greatest SparkFun can produce. This involves setting up the SparkX lab, getting the OtherMills pumping out circuit boards, and  inevitably the occasional containment failure of the blue smoke.

The first product in the SparkX lineup, Product 0, is a breakout board for the MLX90393 magnetometer. This is a pretty nifty magnetometer that Ted Yapo over on hackaday.io has used to characterize magnets. Really, though, the SparkX Product 0 is exactly what it says on the tin: a breakout board that is just an experiment, comes with no guarantees or support. It is the heart of what Sparkfun set out to do twenty years ago.

Friday Hack Chat: Designing RF Products

This Friday, we’re talking RF. Join us for a discussion on designing RF products with Hackaday’s very own Jenny List. It’s all happening in the Hack Chat on hackaday.io.

jennylisthackchattake1-01When Jenny isn’t busy writing for Hackaday, she sits on the board of the Oxford Hackspace. She’s the brains behind Language Spy, and sells electronic kits that include receivers, filters, and RF breakout boards. She’s extremely active on hackaday.io, and has used a Pi Zero to transmit across the Atlantic.

As usual, we’re starting this Hack Chat at Noon, Pacific time on Friday (or Friday 20:00 GMT). Here’s a handy countdown for the event.

Here’s How To Take Part:

join-hack-chatOur Hack Chats are live community events on the Hackaday.io Hack Chat group messaging.

Log into hackaday.io, visit that page, and look for the ‘Join this Project’ Button. Once you’re part of the project, the button will change to ‘Team Messaging’, which takes you directly to the Hack Chat.

You don’t have to wait until Friday; join whenever you want and you can see what the community is talking about.

Upcoming Hack Chats

The Hack Chats on hackaday.io are quickly becoming a thing. Already, we’ve had a pantheon of embedded systems gods including Lady Ada of Adafruit, Sprite_tm, and bunnie.

In March, we’re going to have a Hack Chat with Raspberry Pi engineer Roger Thornton, and a mechanical manufacturing Hack Chat with Fictiv. You can check out all the upcoming Hack Chats right here.

Hackaday Links: February 12, 2017

Taking small LCD screens, a tiny computer running Linux, and a 3D printed enclosure to build miniature versions of old computers is a thing now. Here’s [Cupcakus]’s tiny little Apple II, complete with Oregon Trail. This Apple II is running on a C.H.I.P., uses a 3s lithium battery from a drone, and works with a Bluetooth keyboard and joystick. Yes, the power button on the monitor works.

At Hackaday, we get a lot of emails from people asking the most important question ever: “how do you become a hardware hacker?” [Tex Projects] lays it all out on the line. All you need to do is to buy five of something every time you need one. Need some header pins? Buy five. A sensor? five. Come to the realization that anything you build could be bought for less money.

Are we still doing low-poly Pokemon? [davedarko] has an idea for the Sci-Fi contest we’re running. He’s going to give children seizures. He’s refreshing a project of mine by putting lights, blinkies, and noisy things in a 3D printed Porygon, the original 3D printed Pokemon. Porygon was the subject of that one episode of the Pokemon cartoon that sent 635 Japanese children to the hospital. The episode was banned in America, but it was actually Pikachu that caused the flashing lights.

‘Member Clickspring? He’s the guy who made a fantastic mechanical clock using nothing except a few bits of brass, a blowtorch, a tiny mill and lathe, and a lot of patience. Now he’s building the Antikythera mechanism. The Antikythera mechanism is a 2000-year-old device designed to calculate the phases of the moon, the motion of the planets, and other local astronomical phenomena. This is going to be a masterpiece, and will eventually end up in a museum, so be sure to subscribe to his YouTube channel.

The Most Sensational Calipers On The Planet!

Everyone here probably has a pair of cheap Chinese calipers kicking around the workbench. This means everyone here also knows how quickly the batteries in these handy little tools die. [Thosnbn] also noticed this, but instead of simply complaining and wishing the problem would go away, he decided to do something about it. He built a battery pack for his calipers, giving this tool a two year battery life.

The idea for this build came after [thosnbn]  completely destroyed a pair of these cheap calipers. At the time, the fix was to tape a AA battery to the tool, and solder wires directly to the contact pads for the tiny button cell battery. This fix worked, and after dealing with the ugliest tool known to man for a few years, [thosnbn] decided to clean it up a little.

The new battery enclosure was designed in Fusion360, includes handy features like a switch, and is completely 3D printed. It took a few weeks for [thosnbn] to get all the parts to fit together correctly, but the end result is great. This battery pack fits neatly on the back of the calipers, holds a single AA battery, and the lid is tightly secured with a pair of machine screws.

Unfortunately, [thosnbn] chose to share this project on imgur, a site that does not support sharing .stl or other 3D printer files. It does, however, serve as inspiration for you to make your own battery pack for a pair of cheap calipers.

The Mother Of All Paper Cuts

A Dremel is a fantastically handy tool to have around the workbench, but there is one glaring and obvious downside: you will always run out of cut-off discs. if you’re trying to break into a fancy snap-fit enclosure that has been inexplicably glued together, you’ll invariably need to run down to the hardware store to shell out some cash for a tiny tube of cut-off disks.

[KB9RLW] has the answer to this problem. He’s cutting wood and plastic with paper discs spinning at 35,000 RPM.

The paper used for this application is just a piece of junk mail or heavy, probably glossy card stock. After poking a hole in this piece of paper, tracing a circle with a homemade compass, and cutting out the cutting disk with a pair of scissors, this cut-off disc is easily mounted in the standard Dremel mandrel.

The test cut [KB9RLW] shows us is on a plastic wall wart that’s a glued together, snap-fit mess. The paper cut-off wheel makes short work of this nigh-impenetrable brick of plastic, revealing the electronic goodies inside. This cut-off wheel will also cut through small bits of wood, like a bit of molding.

After cutting halfway through the wooden molding, the paper disc quickly disintegrates — this is the same behavior we last year when this trick was being used on a table saw. But any home should get more than enough junk mail for a steady supply of paper Dremel cut-off discs. While this new attachment for your fancy rotary tool won’t last very long, it is a very expedient way to get into bits of electronics without paying Dremel several cents for a cut-off disc.

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