Visible Light CT Scanner Does Double Duty

March 17, 2018 by Dan Maloney 21 Comments

If you’ve ever experienced the heartbreak of finding a seed in your supposedly seedless navel orange, you’ll be glad to hear that with a little work, you can protect yourself with an optical computed tomography scanner to peer inside that slice before popping it into your mouth.

We have to admit to reading this one with a skeptical eye at first. It’s not that we doubt that a DIY CT scanner is possible; after all, we’ve seen examples at least a couple of times before. The prominent DSLR mounted to the scanning chamber betrays the use of visible light rather than X-rays in this scanner — but really, X-ray is just another wavelength of light. If you choose optically translucent test subjects, the principles are all the same. [Jbumstead]’s optical CT scanner is therefore limited to peeking inside things like slices of tomatoes or oranges to look at the internal structure, which it does with impressive resolution.

This scanner also has a decided advantage over X-ray CT scanners in that it can image the outside of an object in the visible spectrum, which makes it a handy 3D-scanner in addition to its use in diagnosing Gummi Bear diseases. In either transmissive or reflective mode, the DSLR is fitted with a telecentric lens and has its shutter synchronized to the stepper-driven specimen stage. Scan images are sent to Matlab for reconstruction of CT scans or to Photoscan for 3D scans.

The results are impressive, although it’s arguably more useful as a scanner. Looking to turn a 3D-scan into a 3D-print? Photogrammetry is where it’s at.

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Capacitive And Resistive Touch Sensors For Wearables

March 17, 2018 by Brian Benchoff 5 Comments

When you look at switching solutions for electronic wearables, your options are limited. With a clever application of conductive fabric and thread, you can cobble together a simple switch, but the vast array of switch solutions is much more than that. This one is different. The zPatch from [Paul Strohmeier], [Jarrod Knibbe], [Sebastian Boring], and [Kasper Hornæk] at the Human-Centred Computing Section at the University of Copenhagen gives eTextiles capacitive and resistive input. It’s a force sensor, a pressure sensor, and a switch, all made completely out of fabric.

The design of this fabric touch sensor is based around a non-woven resistive fabric made by Eeonyx. This fabric is piezo-resistive when compressed. This material is sandwiched between two layers of silver-plated polyamide fabric, which is then connected to the analog input of a microcontroller. On top of all this is a polyester mesh, with everything held together with iron-on sheets.

Reading this sensor with a microcontroller is extremely similar to a capacitive touch sensor made out of copper and FR4. All the code is available in a repo, and all the materials to reproduce this work can be found in the various links provided by the team. That last point — reproducibility — is huge for an academic work. Not only did the team manage to come up with something interesting, they actually provided enough documentation to reproduce their build.

In the video below, you can see how this sensor can be used to sense a hand hovering, a light touch, a hard press, or anything in between. Only two analog pins are required for each sensor, making the routing and layout of this eTextile should be relatively easy to integrate into clothing. It’s a great build, and we can’t wait to see the community pick up on these really cool sensors.

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3D Printed Stethoscope Makes The Grade

March 17, 2018 by Tom Nardi 22 Comments

On the off chance that initiatives like the Hackaday Prize didn’t make it abundantly clear, we believe strongly that open designs can change the world. Putting technology into the hands of the people is a very powerful thing, and depending on where you are or your station in life, can quite literally mean the difference between life and death. So when we saw that not only had a team of researchers developed a 3D printable stethoscope, but released everything as open source on GitHub, it’s fair to say we were pretty interested.

The stethoscope has been in development for several years now, but has just recently completed a round of testing that clinically validated its performance against premium brand models. Not only does this 3D printed stethoscope work, it works well: tests showed its acoustic performance to be on par with the gold standard in medical stethoscopes, the Littmann Cardiology III. Not bad for something the researchers estimate can be manufactured for as little as $3 each.

All of the 3D printed parts were designed in OpenSCAD (in addition to a Ruby framework called CrystalSCAD), which means the design can be evaluated, modified, and compiled into STLs with completely free and open source tools. A huge advantage for underfunded institutions, and in many ways the benchmark by which other open source 3D-printable projects should be measured. As for the non-printed parts, there’s a complete Bill of Materials which even includes links to where you can purchase each item.

The documentation for the project is also exceptional. It not only breaks down exactly how to print and assemble the stethoscope, it even includes multi-lingual instructions which can be printed out and distributed with kits so they can be assembled in the field by those who need them most.

From low-cost ultrasounds to truly personalized prosthetics, the future of open source medical devices is looking exceptionally bright.

[Thanks to Qes for the tip]

Balloons And Bubbles Make For Kid-Friendly Robot Deathmatch

March 17, 2018 by Dan Maloney 6 Comments

Because nothing says “fun for kids” like barbed wire and hypodermic needles, here’s an interactive real-world game that everyone can enjoy. Think of it as a kinder, gentler version of Robot Wars, where the object of the game is to pop the balloon on the other player’s robot before yours get popped. Sounds simple, but the simple games are often the most engaging, and that sure seems to be the case here.

The current incarnation of “Bubble Blast” stems from a project [Niklas Roy] undertook for a festival in Tunisia in 2017. That first version used heavily hacked toy RC cars controlled with arcade joysticks. It was a big hit with the crowd, so [Niklas] built a second version for another festival, and incorporated lessons learned from version 1.0. The new robots are built from scratch from 3D-printed parts. Two motors drive each bot, with remote control provided by a 433-MHz transceiver module. The UI was greatly improved with big trackballs, also scratch built. The game field was expanded and extra obstacles were added, including a barbed wire border as a hazard to the festooned bots. And just for fun, [Niklas] added a bubble machine, also built from scratch.

The game looks like a ton of fun, and seems like one of those things you’ve got to shoo the adults away from so the kids can enjoy it too. But if you need more gore from your robot deathmatch than a limp balloon, here’s a tabletop robot war that’s sure to please.

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Lockheed Shares Satellite Connectivity Options

March 17, 2018 by Kerry Scharfglass 12 Comments

In an unusual turn of events, Lockheed Martin has released technical “payload accommodation information” for three of their satellite busses. In layperson’s terms, if you wanted to build a satellite and weren’t sure what guidelines to follow these documents may help you learn if Lockheed Martin has a platform to help you build it.

An opportunity to check out once-confidential information about satellites sounds like a perfect excuse to dig through some juicy documentation, though unfortunately this may not be the bonanza of technical tidbits the Hackaday reader is looking for. Past the slick diagrams of typical satellites in rocket fairings, the three documents in question primarily provide broad guidance. There are notes about maximum power ratings, mass and volume guidelines, available orbits, and the like. Communication bus options are varied; there aren’t 1000BASE-T Ethernet drops but multiply redundant MIL-STD-1553B might come standard, plus telemetry options for analog, serial, and other data sources up to 100 Mbps. Somewhat more usual (compared to your average PIC32 datasheet) are specifications for radiation shielding and it’s effectiveness.

In the press release EVP [Rick Ambrose] says “we’re sharing details about the kinds of payloads we can fly…” and that’s exactly what these documents give us. Physical ballpark and general guidelines about what general types of thing Lockheed has capability to build launch. Hopefully the spirit of openness will lead to the hoped-for increase in space utilization.

If you take Lockheed up on their offer of satellite development, don’t forget to drop us a tip!

[Via the Washington Post]

Google Builds A Synthesizer With Neural Nets And Raspberry Pis.

March 16, 2018 by Brian Benchoff 16 Comments

AI is the new hotness! It’s 1965 or 1985 all over again! We’re in the AI Rennisance Mk. 2, and Google, in an attempt to showcase how AI can allow creators to be more… creative has released a synthesizer built around neural networks.

The NSynth Super is an experimental physical interface from Magenta, a research group within the Big G that explores how machine learning tools can create art and music in new ways. The NSynth Super does this by mashing together a Kaoss Pad, samples that sound like General MIDI patches, and a neural network.

Here’s how the NSynth works: The NSynth hardware accepts MIDI signals from a keyboard, DAW, or whatever. These MIDI commands are fed into an openFrameworks app that uses pre-compiled (with Machine Learning™!) samples from various instruments. This openFrameworks app combines and mixes these samples in relation to whatever the user inputs via the NSynth controller. If you’ve ever wanted to hear what the combination of a snare drum and a bassoon sounds like, this does it. Basically, you’re looking at a Kaoss pad controlling rompler that takes four samples and combines them, with the power of Neural Networks. The project comes with a set of pre-compiled and neural networked samples, but you can use this interface to mix your own samples, provided you have a beefy computer with an expensive GPU.

Not to undermine the work that went into this project, but thousands of synth heads will be disappointed by this project. The creation of new audio samples requires training with a GPU; the hardest and most computationally expensive part of neural networks is the training, not the performance. Without a nice graphics card, you’re limited to whatever samples Google has provided here.

Since this is Open Source, all the files are available, and it’s a project that uses a Raspberry Pi with a laser-cut enclosure, there is a huge demand for this machine learning Kaoss pad. The good news is that there’s a group buy on Hackaday.io, and there’s already a seller on Tindie should you want a bare PCB. You can, of course, roll your own, and the Digikey cart for all the SMD parts comes to about $40 USD. This doesn’t include the OLED ($2 from China), the Raspberry Pi, or the laser cut enclosure, but it’s a start. Of course, for those of you who haven’t passed the 0805 SMD solder test, it looks like a few people will be selling assembled versions (less Pi) for $50-$60.

Is it cool? Yes, but a basement-bound producer that wants to add this to a track will quickly learn that training machine learning algorithms cost far more than playing with machine algorithms. The hardware is neat, but brace yourself for disappointment. Just like AI suffered in the late 60s and the late 80s. We’re in the AI Renaissance Mk. 2, after all.

Continue reading “Google Builds A Synthesizer With Neural Nets And Raspberry Pis.” →

3D Printed Antenna Is Broadband

March 16, 2018 by Al Williams 20 Comments

Antennas are a tricky thing, most of them have a fairly narrow range of frequencies where they work well. But there are a few designs that can be very broadband, such as the discone antenna. If you haven’t seen one before, the antenna looks like — well — a disk and a cone. There are lots of ways to make one, but [mkarliner] used a 3D printer and some aluminum tape to create one and was nice enough to share the plans with the Internet.

As built, the antenna works from 400 MHz and up, so it can cover some ham bands and ADS-B frequencies. The plastic parts act as an anchor and allow for coax routing. In addition, the printed parts can hold a one-inch mast for mounting.

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