Hackaday Prize Entry: The Strength Of 3D Printed Parts

[Sam Barrett] is doing something that is sorely needed. He’s doing real materials research on FDM parts.

There’s nothing wrong with the rough experiments like hanging a 1 L bottle of water from the end of a rectangular test print to compare strengths. We also have our rules-of-thumb, like expecting the print to perform at 30% of injection molded strength. But these experiments are primitive and the guidelines are based on hearsay. Like early metallurgy or engineering; 3D printing is full of made-up stuff.

What [Sam] has done here is really amazing. He’s produced a model of a printed ABS part and experimentally verified it to behave close enough to the real thing. He’s also set a method for testing and proposed a new set of questions. If it couldn’t be better, he also included his full research notebook. Make sure to read the FDMProperties-report (PDF) in the files section of Hackaday.io.

Sam finally answered a question we've had of what it looks like when the printer over extrudes.
Sam finally answered a question we’ve had of what it looks like when the printer over extrudes.

If research like this is being done elsewhere, it’s either internal to a large 3D printer manufacturer, or it’s behind a paywall so thorough only the Russians can help a regular peasant get through to them. Anyone with access to a materials testing lab can continue the work (looking at you every single engineering student who reads this site) and begin to help everyone achieve an understanding of 3D printed parts that could lead to some really cool stuff one day.

Squirrel Café To Predict The Weather From Customer Data

Physicist and squirrel gastronomer [Carsten Dannat] is trying to correlate two critical social economical factors: how many summer days do we have left, and when will we run out of nuts. His research project, the Squirrel Café, invites squirrels to grab some free nuts and collects interesting bits of customer data in return.

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JumpRoaCH is Kind Of Cute, Kind Of Creepy

There’s a theory that the fear of scurrying things is genetic. Likewise, a similar theory arose about the tendency for humans to find helpless things cute. After all, our useless babies do best in a pest free environment. This all could explain why we found this robotic roach to be both a little cute and a little creepy.

The university sponsored project, JumpRoaCH, is a collaboration between South Korea’s SNU Biorobotics Lab and Berkeley’s Biomimetic Millisystems Lab. Imitating insects has been a popular avenue for robotic research, and often results in very interesting experiments.

This robot looks like a ladybug going through its rebellious teen phase. It runs on six hook shaped legs which allow it to traverse a wider array of surfaces than wheels would, at the expense of speed and higher vibrations. The robot does a very convincing, if wobbly, scurry across the surface of its test table.

It also has a secret attack in the form of a single Rockem Sockem Robot arm located on its belly. With a powerful burst, the arm can launch the robot up a few feet to a higher surface. If the robot lands on its wheels the researchers high-five. If the robot lands on its back, it can use its ,”wings,” to flip itself right-side-up again.

The resulting paper (PDF file) has a nice description of the robot and its clever jumping mechanism. At least if these start multiplying like roaches, hackers will never short for tiny motors for their projects. Video after the break.

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Highlights From Robotic Shipwreck Exploration

DIY Research Vessel in use, while ROV is busy below. [Source: NYT]
DIY Research Vessel in use, while ROV is busy below. [Source: NYT]
OpenROV shared the results of their June 2016 underwater expedition to locate and robotically explore the wreck of the S.S. Tahoe, currently sitting at a depth of 150m in Lake Tahoe. Back in 1940 the ship was intentionally scuttled in shallow water, but unexpectedly slid to a much deeper depth. OpenROV used a modified version of their new Trident design to dive all the way down to the wreck and take a good look at things, streaming it over the internet in the process.

We previously covered the DIY research vessel that was designed and created as a floating base station for the ROV while it located and explored the wreck, and now the results are in! The video highlights of the expedition are below, as is a video tour of the ROV used and the modifications required to enable it to operate at 150m.

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Your Quadcopter Has Three Propellers Too Many

While studying failure modes for quadcopters, and how to get them safely to the ground with less than a full quad of propellers, a group of researchers at the Institute for Dynamic Systems and Control at ETH Zurich came up with a great idea: a mode of flight that’s like the controlled spinning descent of a maple seed.

The Monospinner runs on the absolute minimum number of moving parts. Namely, one. Even a normal helicopter has a swash plate for adjustable blade pitch, and a tail rotor to keep it from spinning. Give up the idea that you want to keep it from spinning, and you can achieve controlled flight with a lot less. Well, one motor and a whole lot of math and simulation.

The Monospinner is carefully weighted so that it’s as stable as possible while spinning, but so far it’s unable to spin itself up from a standstill. In initial tests, they attached it to a pivot to help. The best part of the video (below) is when the researcher throws it, spinning, into the air and it eventually stabilizes. Very cool.

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Teslaphoresis: Tesla Coil Causes Self-Assembly In Carbon Nanotubes

teslaphoresis_strings_1

This significant discovery in nanotechnology could also be the first practical use of a Tesla coil in modern times that goes beyond fun and education. A self-funded research team at Rice University has found that unordered heaps of carbon nanotubes will self-assemble into conductive wires when exposed to the electric field of a strong Tesla coil. The related paper by lead author and graduate student [Lindsey R. Bornhoeft], introduces the phenomenon as “Teslaphoresis”. Continue reading “Teslaphoresis: Tesla Coil Causes Self-Assembly In Carbon Nanotubes”

Reverse-Engineering debugWire

Has this ever happened to you? You start out on a reverse-engineering project, start digging in, and then get stumped. Then you go looking on the Internet for help, and stumble across someone who’s already done exactly what you’re trying to do?

[Geekabit] wrote us with a version of this tale of woe. In his case, the protocol to be reversed was Atmel’s debugWire protocol for debugging on low-pin-count parts. There are a number of websites claiming it’s “secret” or whatever, but it actually looks like it’s just poorly documented. Anyway, [RikusW] seems to have captured all of the signals way back in 2011. Good job!

The best part of [geekabit]’s story is that he had created the Wikipedia page on debugWire himself to inspire collaboration on reverse-engineering the protocol, and someone linked in [RiskusW]’s work. When [geekabit] picked up the problem again a bit later, he did a bit of web research and found it solved — on the page that he started.

Maybe it’s not a tale of woe after all, but a tale of unintentional collaboration. Anyway, it serves as a reminder that if you’re interested in the destination more than the voyage of discovery, it never hurts to do your research beforehand. And now we all know about the low-level details of the debugWire protocol. Anyone written up a driver yet?

Thanks [geekabit] for the tip and the story! Image from ATmega32-AVR, which explains nicely how to use the Dragon in debugWire mode.