Author: Al Williams

4339 Articles

PETamentor2 Is Latest To Turn Bottles Into Filament

October 16, 2022 by 24 Comments

[Ondřej Šraitr] has several videos, including the one you can watch below, about his PETamentor2 — a machine for turning PET bottles into printable filament. You can grab the files on Thingiverse, and there aren’t many parts you have to buy.

The device looks good, and from the videos, it appears to work well. A blade slices the bottle into a strip that feeds what is essentially a hot end that pushes out the filament. The blade is adjustable to set the amount of plastic fed at any given time which is important because you need enough to create a solid piece of filament but not any more than that.

Surprisingly, the bill of materials doesn’t include any sort of microcontroller. There is a PWM speed control module to drive the 7 RPM motor and a temperature controller. Of course, you need a power supply, a heater block and a heater. The nozzle is, oddly enough, a standard 0.4 mm nozzle. You drill it out to 1.5 mm and die swell takes care of getting to the final 1.75 mm size.

It takes about 45 minutes to eat up what looks like a 1-liter bottle. The filament produced looks good in the video. We aren’t sure, but we think that was a roll of solder used as a ballast weight on top of the bottle keeping it moving in a downward direction. Bottles imply wetness, of course, so after producing the filament, it needs to be dried.

This is the second version of the machine and we were a bit surprised that we never saw a video of the filament in use. But it looks like it would work and it isn’t like we haven’t seen this technique used before. In fact, we’ve seen it several times. We can’t remember any that looked as stylish as the PETamentor2, though, and we are interested to hear about anyone’s results with the resulting filament.

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Fourteen-Legged Cell Carries Nature’s Tiny Computer

October 16, 2022 by 12 Comments

Computers are, after all, frighteningly complex state machines. Quite of bit of the software we write can be modeled as a state machine, too. A great technological achievement by humans? Turns out, state machines exist in some of nature’s tiniest natural computers, according to biologists studying Euplotes eurystomus, a kind of water-dwelling eukaryote. This single-cell organism uses fourteen protolegs known as cirri that move in a particular gait, in response to certain stimuli.

As you might expect, a single-celled organism doesn’t have the infrastructure to support a brain, so scientists wondered what could control the way the beast walks using the cirri. The answer was fibers made of bundles of microtubles that acted as a mechanical state machine.

While we are used to state machines using bi-stable electronic elements, older machines often used cams and microswitches along with a timing motor. For example, a phone answering machine might have a three-minute motor. One cam would depress a micro switch to run the outgoing message for 15 seconds. Then another cam would depress a microswitch to start recording, and a final switch and cam would keep the motor running until the very end. To start the process, a ringing phone would goose the motor so that that last cam engaged. Simple and no computer needed. The “brain fibers” of the Euplotes seem to work in a similar way. They enforce which states can be reached from what other states and react to outside stimuli, as well.

Is any of this practical? Maybe not, although we often see technology mimic biological systems. But we can’t help but wonder if future microscopic-scale machines might not need this same sort of mechanical state machine for many purposes, including locomotion.

You can apparently make single-cell organisms your servants, more or less. We’ve covered state machines many times if you need a refresher.

Laser Engraving, Up Close

October 15, 2022 by 11 Comments

You know you aren’t supposed to watch your laser while it is cutting or engraving. But [Alex] hosted Wired in his studio and showed them how lasers engrave metal with a fiber laser. You can see the video below.

If you haven’t used a fiber laser, you might be surprised that while a 60 W model can burn metal, it does absolutely nothing to [Alex’s] hand. We wouldn’t try that, by the way, with the common diode lasers you see in most hacker’s labs these days. The video isn’t terribly technical, but it is interesting to see different metals succumb to the powerful laser. There are a few tips about marking different metals in different ways and how to deal with thermal expansion and other effects.

Fiber lasers aren’t as common as diode engravers in private shops, but we assume it is just a matter of time before they get cheaper. Not to mention their widespread use commercially means surplus units might become available, too.

If you are interested in lasers, [Alex’s] YouTube channel has quite a few interesting videos to check out. If you need more power, how’s 200 kW? Then again, even 20 W will get you something useful.

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Publish Or Perish: Data Storage And Civilization

October 13, 2022 by 120 Comments

Who do you think of when you think of ancient civilizations? Romans? Greeks? Chinese? India? Egyptians?  What about the Scythians, the Muisca, Gana, or the Kerma? You might not recognize that second group as readily because they all didn’t have writing systems. The same goes, to a lesser extent, for the Etruscans, the Minoans, or the inhabitants of Easter Island where they wrote, but no one remembers how to read their writing. Even the Egyptians were mysterious until the discovery of the Rosetta stone. We imagine that an author writing in Etruscan didn’t think that no one would be able to read the writing in the future–they probably thought they were recording their thoughts for all eternity. Hubris? Maybe, but what about our documents that are increasingly stored as bits somewhere?

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Tiny Thin Client Is Small But Compatible

October 13, 2022 by 10 Comments

We were impressed with [moononournation’s] tiny thin client project. It claims to use an Arduino, but as you might guess it is using the Arduino software along with a network-enabled microcontroller like an ESP32. The impressive part is that it is standards-compliant and implements VNC’s RFB protocol.

The original coding for RFB on Arduino is from [Links2004] and armed with that, the thin client is probably easier to create than you would guess. However, this project wanted to use a larger screen and found that it led to certain problems. In particular, the original code had a 320×240 display. This project was to use an 800×480 display, but with the limits on the ESP32, the frame rate possible would be under 7 frames per second. The answer was to combine a 16-bit parallel interface with better compression back to the VNC server.

The little keyboard is probably not very practical, but it is compact. That would be another easy thing to modify. Currently, the keyboard uses I2C, but it would be straightforward to change things up. This would be a worthy base to build a bigger project on top. A 3D printed enclosure would be nice, too.

We’ve seen a number of projects built around commercial thin clients. Some from defunct businesses are good sources for obscure parts, too.

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Watermelon CNC Uses Lazy Susan

October 12, 2022 by 27 Comments

It is the time of year when a lot of people in certain parts of the world carve pumpkins. [Gonkee] is carving a watermelon, which we assume is similar. He decided to make a CNC machine to do the carving for him. The unusual part is the use of two lazy Susans to make a rotary carving machine. You can see the result in the video below.

The hardware is clever and there is software that lets you do drawings, although we were hoping for something that would process gcode or slice STL. That would be a worthy add-on project. There were a few iterations required before the Melon Carver 3000 worked satisfactorily. Seeing a carving tool operating on two circles gives us a lot of ideas. We aren’t sure how sturdy the mounts are, so don’t plan on carving aluminum without some changes, but we suspect it is possible.

Then again, a laser head mounted on the frame would have probably made short work of the melon, and wouldn’t require much mechanical stiffness. It would, however, take a little effort to keep it in focus. So many ideas to try!

Watermelon is a popular hacking medium, apparently. There’s even one that holds a GameBoy.

ARM Programming By Example

October 11, 2022 by 40 Comments

The ARM processor is popping up everywhere. From Raspberry Pis, to phones, to Blue Pill Arduino-like boards, you don’t have to go far to find an ARM processor these days. If you program in C, you probably don’t care much or even think about it. But do you know ARM assembly language? Well, if you look at it one way, it can’t be too hard. The CPU only has about 30 distinct operations — that’s why it is called RISC. Of course, sometimes fewer instructions actually make things more difficult. But you can get a great starting tutorial with the 21 programs on the ARM Assembly by Example website.

You need a 32-bit ARMv6 or better — so Raspberry Pi will work here. The compiler, of course, is gcc and all the associated tools. if you have the right hardware, there are sections on using the floating point unit and the NEON co-processor, too.

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