3D Printering: Which Raspberry Pi Is Best At Slicing In Octoprint?

May 3, 2018 by 22 Comments

OctoPrint is arguably the ultimate tool for remote 3D printer control and monitoring. Whether you simply want a way to send G-Code to your printer without it being physically connected to your computer or you want to be able to monitor a print from your phone while at work, OctoPrint is what you’re looking for. The core software itself is fantastic, and the community that has sprung up around the development of OctoPrint plugins has done an incredible job expanding the basic functionality into some very impressive new territory.

RAMBo 3D controller with Pi Zero Integration

But all that is on the software side; you still need to run OctoPrint on something. Technically speaking, OctoPrint could run on more or less anything you have lying around the workshop. It’s cross platform and doesn’t need anything more exotic than a free USB port to connect to the printer, and people have run it on everything from disused Windows desktops to cheap Android smartphones. But for many, the true “home” of OctoPrint is the Raspberry Pi.

As I’ve covered previously, the Raspberry Pi does make an exceptional platform for OctoPrint. Given the small size and low energy requirements of the Pi, it’s easy to integrate into your printer. The new Prusa i3 MK3 even includes a header right on the control board where you can plug in a Raspberry Pi Zero.

But while the Raspberry Pi is more than capable of controlling a 3D printer in real-time, there has always been some debate about its suitability for slicing STL files. Even on a desktop computer, it can sometimes be a time consuming chore to take an STL file and process it down to the raw G-Code file that will command the printer’s movements.

In an effort to quantify the slicing performance on the Raspberry Pi, I thought it would be interesting to do a head-to-head slicing comparison between the Pi Zero, the ever popular Pi 3, and the newest Pi 3 B+.

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More Details On That First Home-Made Lithographically Produced IC

May 3, 2018 by 19 Comments

A few days ago we brought you news of [Sam Zeloof]’s amazing achievement, of creating the first home-made lithographically produced integrated circuit. It was a modest enough design in a simple pair of differential amplifiers and all we had to go on was a Twitter announcement, but it promised a more complete write-up to follow. We’re pleased to note that the write-up has arrived, and we can have a look at some of the details of just how he managed to produce an IC in his garage. He’s even given it a part number, the Zeloof Z1.

For ease of manufacture he’s opted for a PMOS process, and he is using four masks which he lists as the active/doped area, gate oxide, contact window, and top metal. He takes us through 66 different processes that he performs over the twelve hours of a full production run, with comprehensive descriptions that make for a fascinating run-down of semiconductor manufacture for those of us who will never build a chip of our own but are still interested to learn how it is done. The chip’s oblong dimensions are dictated by the constraints of an off-the-shelf Kyocera ceramic chip carrier, though without a wire bonding machine he’s unable to do any more than test it with probes.

You can read our reporting of his first announcement, but don’t go away thinking that will be all. We’re certain [Sam] will be back with more devices, and can’t wait to see the Z2.

Playing Jedi Mind-Tricks On Your TV

May 3, 2018 by 4 Comments

Gesture-enabled controls mean you get to live out your fantasy of wielding force powers. It does, however, take a bit of hacking to make that possible. Directly from the team at [circuito.io] comes a hand gesture controller for Jedi mind-trick manipulation of your devices!

The star of the show here is the APDS-9960 RGB and gesture sensor, with an Arduino Pro Mini 328 doing the thinking and an IR transmitter LED putting that to good use. The Arduino Sketch is a chimera of two code examples for IR LEDs and the gesture sensor — courtesy of the always estimable Ken Shirriff, and SparkFun respectively.

Of course, you can have the output trigger different devices, but since this particular build is meant to control a TV the team had to use a separate Arduino and IR receiver to discover the codes for the commands they wanted  to use. Once they were added to the Sketch, moving your hand above the sensor in X, Y or Z-axes executes the command. Voila! — Jedi powers.

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Raspberry Pi Is Up Up And Away

May 2, 2018 by 3 Comments

BACAR — Balloon Carrying Amateur Radio — is just what it sounds like. A high-altitude balloon carries experiments and communicates via amateur radio. [ZR6AIC] decided to fly a payload in a local BACAR experiment. The module would send its GPS position via the APRS network and also send a Morse code beacon every seven minutes. It also sends other data such as temperature, and has an optional camera fitted.

The hardware used was the ubiquitous Raspberry Pi along with an associated daughterboard for transmitting on the 2 meter ham band. An RTL dongle took care of the receive portion and another dongle provided GPS. A DS18B20 temperature sensor provides the temperature data.

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Soda Can Art

May 2, 2018 by 37 Comments

A can of soda costs about half a dollar, and once you’re done with the sugary syrup, most cans end up in the trash headed for recycling. Some folks re-use them for other purposes, but we’re guessing no one up-cycles them quite like artist [Noah Deledda] does. He turns them into pieces of Soda Can art that sell for anywhere between $2000 to $3000 a pop.

Don’t be fooled by that smashing hit in the GIF. It’s just some trick photography that [Noah] did to impress people. If you looked at the end product without the back story first, you’d think the cans were manipulated in to contorted shapes using some kind of mechanical assistance, at the very least, or probably a purpose-built machine.

But [Noah Deledda] does it with bare hands. This is the bare-metal version of Origami. While on a road trip many years ago, he was bereft of electronic devices to keep him busy. Playing with an empty can of soda, he started denting and squeezing the thin metal in to an abstract shape. That’s when the artist in him realized that he was playing with an exciting new medium. After making some abstract art pieces out of empty cans of a vermillion bovine energy drink, he figured it would look much more awesome if he could remove all the paint from the cans and give them a smooth, polished, natural finish. He made a little machine that rotates the cans so he can strip the paint and bring the cans to a high polish. The technique is simple but requires a lot of patience, practice, time and skill, not to mention that it will cause a lot of pain in the thumb.

If you’ve ever been to Japan and drank a can of Kirin Hyoketsu, you’d notice the un-opened can is smooth, but immediately changes to a pattern of indented diamonds once you open it. That design was created by Kyoro Miura, well-known for the Miura Fold that lets you fold and unfold large sheets of paper in one smooth movement. Like that discarded map in the glove box of the car you’re riding in, while playing with an empty can of soda.

If you want to hone some ambidextrous skills, this would be a good way to do it while on your next road, plane or train trip. Check out the two videos embedded below. In the second one, you can see snapshots of the design process.

Thanks, [Keith O], for this tip.

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Oddball Mercury Vapor Rectifier Is A Tube Geek’s Delight

May 2, 2018 by 29 Comments

Even if you aren’t a tube aficionado, you can’t help but be mesmerized by the blue glow inside a mercury vapor rectifier when it operates. It looks less like early 20th century tech and more like something that belongs on a Star Trek set. [Uniservo] acquired an 866 rectifier that was interesting due to the markings, which he explains in detail in the video below. Most people though will probably want to skip to closer to its end to see that distinctive blue glow. The exact hue depends on the mercury vapor pressure and usually contains a fair amount of ultraviolet light.

These tubes have an interesting history dating back to 1901, the year [Peter Cooper Hewitt] developed a mercury vapor light which was much more efficient than conventional bulbs. They had two main problems, they required some special process to get the mercury inside to vaporize when you turned them on, but worse still, the light was blue-green which isn’t really appropriate for home and office lighting. In 1902 though, [Hewitt] realized the tube would act as a rectifier. Electrons could readily flow out of the mercury vapor that was the cathode, while the carbon anodes didn’t give up electrons as readily. This was important because up until then, there wasn’t an easy way to convert AC to DC. The usual method was to use an AC motor coupled to a DC generator or a similar mechanical arrangement known as a rotary converter.

In later decades the mercury vapor lamp would wind up with a phosphor coating that converted the ultraviolet light to cool white light and became the fluorescent bulb, so while the rectifier mostly gave way to more efficient methods, [Hewitt’s] bulb has been in use for many years.

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The Incredible Shrinking Rework Station

May 2, 2018 by 18 Comments

Anyone who’s ever tried setting up a workbench in a tight space knows the struggle: you want to have all your test equipment and tools out and within arm’s reach, but you just don’t have enough surface area. If you fill the whole bench with your tools, there’s not going to be anywhere left to work. So you either have a bench full of tools that’s uncomfortable to use, or you’re forced to choose what stays out and what gets packed away. Neither is conducive to actually getting work done, which is why you are trying to set up a proper bench in the first place. It’s a vicious cycle.

When faced with that very problem recently, [EEpromChip] decided to take the nuclear option. His Kendal 853D was already a great choice for a small-scale work area since it’s not just a hot air rework station but also offers a soldering iron and bench power supply in one unit. But it was still just a little too long for his bench. The solution? Just run the thing through the bandsaw and cut it in half. Seriously.

Upon opening the 853D up, [EEpromChip] realized the internal layout wasn’t terribly efficient. There was plenty of extra room inside the case to begin with, but if the transformer was removed from the bottom of the case and mounted to the rear it would really cut down the device’s footprint.

After making sure he documented where everything connected, he took all the electronics out of the sheet metal case and cut it down to size on a bandsaw. He then reinstalled circuit boards, and this time mounted the beefy transformer so it hangs over the board rather than sits next to it. The end result is a version of the Kendal 853D which is several inches shorter than before with no impact on functionality.

Turning closets small spaces into dens of Hackerdom has been a topic we’ve discussed previously. Saving every inch is important if you ever hope to move into a grain silo or CNC’d plywood house.