Ask Hackaday: Is PLA Biodegradable?

The most popular plastic for 3D printers is PLA – polylactic acid – a plastic that’s either derived from corn starch, inedible plant detritus, or sugar cane, depending where in the world it was manufactured. Being derived from natural materials, PLA is marketed as being biodegradable. You don’t need to worry about low-poly Pokemon and other plastic trinkets filling landfills when you’re printing with PLA, all these plastic baubles will return to the Earth from whence it came.

3D printers have been around for a few years now, and now objects printed in PLA have been around the sun a few times. A few of these objects have been completely forgotten. How’s that claim of being biodegradable holding up? The results are mixed, and as always, more data is needed.

A few weeks ago, [LazyGecko] found one of his first experiments in 3D printing. In 2012, he was experimenting with tie dying PLA prints by putting his prints in a jar filled with water and blue dye. This jar was then placed in the back of his cupboard and quickly forgotten. 3.5 years later, [LazyGecko] remembered his experiment. Absolutely nothing happened, save for a little bit of blue dye turning the print a pastel baby blue. The print looks and feels exactly like the day it came off the printer.

[LazyGecko]’s blog post was noticed by [Bill Waters], and he has one datum that points to PLA being biodegradable. In 2015, [Bill] printed a filter basket for his fish tank. The first filter basket worked well, but made a small design change a week later, printed out another, and put the first print in storage. He now has two nearly identical prints, one in constant use in a biologically interesting environment, the other sitting on a shelf for a year.

[Bill]’s inadvertent experiment is very close to the best possible experimental design to make the case for PLA biodegradability. The 3D printed filter basket in constant use for a year suffered significant breakdown, and the honeycomb walls are starting to crumble. The ‘inert’ printed filter basket looks like it just came off the build plate.

If that’s not confusing enough, [Bill] also has another print that has spent a year in a fish tank. This end cap for a filter spray bar didn’t see any degradation, despite being underwater in a biologically active environment. The environment is a little different from a filter basket, though; an aquarium filter is designed to break down organics.

To answer the question, ‘is PLA biodegradable,’ the most accurate answer is, ‘maybe’. Three data points in uncontrolled environments isn’t enough to draw any conclusions. There are, undoubtedly, more forgotten 3D prints out there, and more data to back up the claim of PLA being biodegradable.

This is where you come in. Do you have some forgotten prints out there? Your input is needed, the fruits of your labors are evidence, your prints might be decaying and we want to know about it below.

Wall-E Goes Corporate, Offering Telepresence Service

I guess if you are going to build a robot to do something boring like telepresence, you might as well make it cute. That’s obviously what [Andrew Maurer] was thinking when he built a telepresence robot using a Wall-E toy. The result is kind of adorable: Wall-E is holding the 5-inch HDMI screen that shows the video, and can scoot around in true Pixar fashion under remote control.

It’s also a neat build on the inside, using a Raspberry Pi for the brains and an Adafruit MotorHat to control the motors. The original toy didn’t have motors, so he added a new RC gearbox and motors to drive the little fella around. Installed behind Wall-Es eye is a USB webcam. Running behind the scenes is a mumble server that does the audio, a copy of Chromium that shows the video, and an Apache server that feeds the captured video to the other end of the conversation. The whole thing is tied together by a few scripts that kick things off appropriately and allow the user to remotely control Wall-E. It’s a cute build, and hopefully Wall-E can still find his EVE while performing his new corporate duties.

[via reddit]

Geodesic Dome Build At Rev Space Den Haag

[Morphje] has always wanted to build a geodesic dome. The shape and design, and the possibility of building one with basic materials interest him. So with the help of a few friends to erect the finished dome, he set about realising his ambition by building a 9.1 metre diameter structure.

The action took place at Rev Space (Dutch language site), the hackspace in The Hague, Netherlands. [Morphje] first had to create a huge number of wooden struts, each with a piece of tube hammered down to a flat lug set in each end, and with a collar on the outside of the strut to prevent it from splitting. The action of flattening the ends of hundreds of pieces of tube is a fairly simple process if you own a hefty fly press with the correct tooling set up in it, but [Morphje] didn’t have that luxury, and had to hammer each one flat by hand.

The struts are then bolted together by those flattened tube lugs into triangular sections, and those triangles are further bolted together into the final dome. Or that’s the theory. In the video below you can see they make an aborted start assembling the dome from the outside inwards, before changing tack to assemble it from the roof downwards.

This project is still a work-in-progress, [Morphje] has only assembled the frame of the dome and it has no covering or door as yet. But it’s still a build worth following, and we look forward to seeing the finished dome at one or other of the European maker events in the summer.

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Monitor A Serial Port From Anywhere

This simple WiFi serial port monitor would have saved us a lot of trouble. We can’t count how many times where being hooked into an Arduino with USB just to get the serial out has nearly been more trouble than it’s worth. Times where we sat cross-legged on the floor and could choose comfort or accidentally shifting the set-up and ruining everything, but not both.

[Frenky]’s set-up is simple and clever. The Ardunio’s serial out is hooked to an ESP8266. The Arduino spams serial out to the ESP8266 in its usual way. The ESP8266 then pipes all that out to a simple JavaScript webpage. Connect to the ESP8266’s IP with any device in your house, and get a live stream of all the serial data. Neat.

As simple as this technique is, we can see ourselves making a neat little box with TX, RX, GND, and VCC screw terminals to free us from the nightmare of tethering on concrete floors just for a simple test. Video after the break.

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Tiny Open Source Robot

We watched the video introduction for this little open source robot, and while we’re not 100% sure we want tiny glowing eyes watching us while we sleep, it does seem to be a nice little platform for hacking. The robot is a side project of [Matthew], who’s studying for a degree in Information Science.

The robot has little actuated grippy arms for holding a cell phone in the front. When it’t not holding a cellphone it can use its two little ultrasonic senors to run around without bumping into things. We like the passive balancing used on the robot. Rather than having a complicated self-balancing set-up, the robot just uses little ball casters to provide the other righting points of contact.

The head of the robot has plenty of space for whatever flavor of Arduino you prefer. A few hours of 3D printing and some vitamins is all you need to have a little robot shadow lurking in your room. Video after the break.

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Breadboard Colecovision

The Colecovision was a state-of-the-art game console back in 1983. Based around the Z-80, it was almost a personal computer (and, with the Adam add-on, it could serve that function, complete with a daisy wheel printer for output). [Kernelcrash] set out to recreate the Colecovision on a breadboard and kept notes of the process.

His earlier project was building a Funvision (a rebranded VTech Creativision) on a breadboard, so he started with the parts he had from that project. He did make some design changes (for example, generating separate clocks instead of using the original design’s method for producing the different frequencies needed).

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It’s Time The Software People And Mechanical People Sat Down And Had A Talk.

With the advances in rapid prototyping, there’s been a huge influx of people in the physical realm of hacking. While my overall view of this development is positive, I’ve noticed a schism forming in the community. I’m going to have to call a group out. I think it stems from a fundamental refusal of software folks to change their ways of thinking to some of the real aspects of working in the physical realm, so-to-speak. The problem, I think, comes down to three things: dismissal of cost, favoring modularity over understanding, and a resulting insistence that there’s nothing to learn.

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