Derek Schulte: Path Planning For 3D Printers

[Derek Schulte] designed and sells a consumer 3D printer, and that gives him a lot of insight into what makes them tick. His printer, the New Matter MOD-t, is different from the 3D printer that you’re using now in a few different ways. Most interestingly, it uses closed-loop feedback and DC motors instead of steppers, and it uses a fairly beefy 32-bit ARM processor instead of the glorified Arduino Uno that’s running many printers out there.

The first of these choices meant that [Derek] had to write his own motor control and path planning software, and the second means that he has the processing to back it up. In his talk, he goes into real detail about how they ended up with the path planning system they did, and exactly how it works. If you’ve ever thought hard about how a physical printhead, with momentum, makes the infinitely sharp corners that it’s being told to in the G-code, this talk is for you. (Spoiler: it doesn’t break the laws of physics, and navigating through the curve involves math.)

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Thermoacoustic Engine Has Only One Moving Part

Modern internal combustion engines have around 500 parts, with many of them moving in concert with the piston. But have you seen an engine with only one moving part, out of four in total? In the thermoacoustic engine, the power piston is the only part in motion. [YTEngineer] has built a very simple prototype that works on power provided by a tealight.

His little engine, slightly larger than a cigarette lighter, is composed of a test tube that serves as the cylinder, a smaller tube, called the choke, that fits inside the test tube, the stack, which is nothing more than some steel wool, and the power piston. [YTEnginer] nicely explains how the engine works: basically a temperature difference is used to induce high-amplitude sound waves that create the piston’s back-and-forth movement. The engine can be easily converted to an electricity generator by adding a magnet to the piston and a coil surrounding it.

The thermoacoustic engine is a particular type of Stirling engine. They have been proposed as electricity generators for space travel using radioisotopes as the heat source, among other applications. You may be interested in the history of Stirling engines, or perhaps even build a simple one.

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A Singing Arc Lighter

We’ve all been guilty of buying things we want, but don’t need. And that’s how [PodeCoet] found himself in possession of a couple of double-arc electric lighters, thanks to those far-eastern websites purveying cheap goods. ‘Tis the season of giving after all, justified [PodeCoet]. Being a hacker, the obvious thing to do was to make them belt out tinny tunes. If you’re still holding on to your gas lighters, don’t — because these electric ones are ‘oh so hackable’. Dual-arcs are the same, but twice the fun.

[PodeCoet] starts off with a tear down of the lighter, to figure out the schematic and understand how it works. There’s a charger IC for the LiPo, an unidentifiable micro-controller, a pair of FET’s driving a pair of power transistors, which in turn drive the HF output transformer at around 15.6kHz. He guesses that the “original micro-controller is probably an OTP part like a 12C508” but in the absence of a chipID he couldn’t be sure.

Instead of trying to break his head over it, he just swapped in a pin-compatible PIC12F1840. All that’s left to do is to write some quick-n-dirty code and sprinkle it with funny comments in order to modulate the output signal at audio frequencies. His first choice of tune was “We are Number One” by Lazy Town, the Icelandic educational musical comedy children’s television series (phew). But redditors are awesome, and someone asked him to add the “Imperial March” and [PodeCoet] obliged.

Since he was going to gift these lighters, the sneaky hacker added a prank in the code. Every time the button is pressed for more than two seconds, it works as normally expected and a counter is incremented. On the 20th count, and for one time only, the tune is played. No amount of pressing the button will play the tune again, confounding the user to wonder if he was hallucinating. This also helps ensure the lighter does not self-destruct prematurely, since the output transformer is likely designed for low duty cycles. His blog post contains all of the information needed to do this hack along with handy tips to avoid the problems he faced. A “Happy Birthday” tune would be great when lighting some birthday candles, we think.

[PodeCoet] has a fancy for high voltage stuff – check out “Home built Stun Baton turns you into a cop from Demolition Man“. This man surely loves his pranks, as evidenced by “Hacking your Co-Workers Label Makers“. And the farce is strong in this one — “Student trolls anti-Arduino Prof with parasite MCU“.

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RooBee One, An Open-source SLA/DLP 3D Printer

[Aldric Negrier] is no stranger to the 3D printing world. Having built a few already, he designed and built an SLA/DLP 3D printer, named RooBee One, sharing the plans on Instructables. He also published tons of other stuff, like a 3D Printed Syringe Pump Rack and a 3D Scanning Rig And DIY Turntable. It’s really worth while going through his whole Instructables repository.

This open-source 3D printer was inspired by the Cristelia – SLA/LCD 3d printer and the Vulcanus MAX 3D printer (that he designed). RooBee One has an aluminium frame and an adjustable print area of 80x60x200 mm, with up to 150x105x200mm build volume using an ACER DLP projector. In addition, a fan on top of the printer was added to extract the toxic vapours outside and away from the printer operator. The electronics are based on the Arduino MEGA with the RAMPS 1.4 shield and one NEMA 17 stepper motor. As for the Arduino Mega firmware, [Aldric] choose to use Repetier, which he usually uses in his other printers.

The SLA resin he used is the Standard Blend Resin from Fun to Do Resins. These resins tend to release toxic airborne particles, so extra care should be taken to ventilate the area while printing and also do a proper cleaning afterwards.

You can get a glimpse of the printer making a small gear come to life in the following video:

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Mechano-Robotic Flute Made From An Old Shotgun

If you take an object and turn it into something else, does that constitute a hack?  Can a musical robot call to question the ethics of firearms exports? If you take a disabled shotgun and turn it into a flute, does it become an art piece? Deep questions indeed — and deliberately posed by [Constantine Zlatev] along with his collaborators [Kostadin Ilov] and [Velina Ruseva].

The Last Gun — a mechano-robotic flute, as [Zlatev] calls it — is built from recovered industrial parts, played using compressed air, and controlled by an Arduino and Raspberry Pi. After graphing the annual arms exports from the United States, the installation plays a mournful tune for each year that they rise, and a jubilant theme for each year they fall.

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2016: As The Hardware World Turns

Soon, the ball will drop in Times Square, someone will realize you can turn ‘2018’ into a pair of novelty sunglasses, and the forgotten mumbled lyrics of Auld Lang Syne will echo through New Year’s Eve parties. It’s time once again to recount the last 366 days, and what a year it’s been.

Arduino got into an argument with Arduino and Arduino won. We got new Raspberry Pis. Video cards are finally getting to the point where VR is practical. The FCC inadvertently killed security in home routers before fixing the problem. All of this is small potatoes and really doesn’t capture the essence of 2016. It’s been a weird year.

Want proof 2016 was different? This year, Microsoft announced they would provide a Linux ‘shim’ with every version of Windows. By definition, 2016 was the year of the Linux desktop. That’s how weird things have been in 2016.

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NES Classic Edition – Controller Mod

The Nintendo Classic Mini took the world by storm this year — finally, an NES in a cute, tiny package that isn’t 3D printed and running off a Raspberry Pi! It’s resoundingly popular and the nostalgic set are loving it. But what do you do when you’re two hours deep into a hardcore Metroid session and you realize you need to reboot and reload. Get off the couch? Never!

[gyromatical] had already bought an Emio Edge gamepad for his NES Mini. A little poking around inside revealed some unused pads on the PCB. Further investigation revealed that one pad can be used to wire up a reset button, and two others can be used to create a home switch. Combine this with the turbo features already present on the Emio Edge, and you’ve got a pretty solid upgrade over the stock NES Mini pad. Oftentimes, there’s extra functionality lurking inside products that manufacturers have left inactive for the sake of saving a few dollars on switches & connectors. It’s always worth taking a look inside.

Now, back in 2006, the coolest hack was running Linux on everything — and somebody’s already trying to get Linux on the NES Mini.

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