OpenScan 3D Scans All Of The (Small) Things

April 25, 2020 by Donald Papp 22 Comments

The OpenScan project has been updated quite a bit since its inception. OpenScan is an open source, Arduino or Raspberry Pi-based 3D scanner for small objects that uses 3D printed hardware and some common electronic components to create 3D scans using photogrammetry; a process by which a series of still images from different angles are used to create a 3D point cloud of an object, which can then be used to generate a 3D model.

Feature visualization overlays detected features onto the camera preview to help judge quality. Broadly speaking, green is good.

Photogrammetry is a somewhat involved process that relies on consistent conditions, so going through the whole process only to find out the results aren’t up to snuff can be tiresome. Happily, OpenScan offers some interesting new functions such as feature visualization via the web interface, which helps a user judge scan quality and make changes to optimize results without having to blindly cross their fingers quite so much. OpenScan remains a one-person project by [Thomas], who is clearly motivated to improve his design and we’re delighted to see it getting updates.

Embedded below is a video that walks through the installation and web interface. It’s a fairly long and comprehensive, but if you like you can skip directly to [Thomas] demonstrating the interface around the 8:22 mark, or watch it below. Interested in your own unit? [Thomas] has an e-shop for parts and the GitHub repository is right here; the project also has its own subreddit.

Continue reading “OpenScan 3D Scans All Of The (Small) Things” →

You Need More Weird

April 25, 2020 by Elliot Williams 61 Comments

What do you do when you need to solve a problem creatively? Me, I go for a walk, preferably in the woods. It’s about as far away from the desk and computer as possible, and somehow getting outside of the box that is my office helps me to think outside of the metaphorical box as well. Maybe it’s the fresh air, maybe it’s the exercise. Or maybe, it’s putting my physical head in a different (head)space that helps me to think differently.

Psychologists are finding that being outside, being an outsider, or even just being exposed to the straight-up strange can help you think weirder, that is, more creatively. That artists, authors, and other hyper-creative folks are often a little bit odd is almost a cliche. Think of the artists who did their best work while under the influence of drugs, mental illness, or drastic dislocations.

The good news is that you might not have to go so far. Psychologists are able to measure increases in creative problem solving simply by exposing people to weirdness. And you don’t have to go on a magic-mushroom trip to get there either. In one study, this was playing in an upside-down VR world before answering a questionnaire, for instance. Ray Wilson meant it tongue-in-cheek when he suggested that building a silly synthesizer would help you think, but who’s laughing now that science is backing him up?

So if you find yourself, as I do, stuck inside the same four walls, make sure that you break out of the box from time to time. Expose your brain to weird, for your own creativity’s sake. Make some time for a completely wacky project. And of course, read more Hackaday! (We’ve got weird.)

Signal The End Of A Print With MIDI Of Your Choice

April 25, 2020 by Danie Conradie 6 Comments

The end of every 3D print should be a triumphant moment, and deserves a theme song. [FuseBox2R] decided to make it a reality, and wrote tool for converting MIDI tracks to G-code that uses the buzzer on your 3D printer.

The tool is up on GitHub, and uses the M300 speaker command that is available in Marlin and some other 3D printer firmware packages. It takes the form of a static HTML page with in-line JavaScript that converts a midi track to series of speaker commands with the appropriate frequency and duration parameters, using the Tone.js framework. Simply add to your slicer G-code to add a bit of spice to your prints. You can also build a MIDI jukebox using the RAMPS board and LCD you probably have gathering dust somewhere. See the video after the break for a demonstration, including a rendition of the DOOM theme song, and off course Mario Bros.

For more quarantine projects, you can also play MIDI using the stepper motors on your printer, or build a day clock if time is becoming too much of a blur.

Continue reading “Signal The End Of A Print With MIDI Of Your Choice” →

In-Depth Design Of A Flyback Converter

April 25, 2020 by Jenny List 13 Comments

It is tempting to think of analogue and digital domains as entirely distinct, never to touch each other except like a cold war Checkpoint Charlie, through the medium of an ADC or DAC. In reality there are plenty of analogue effects upon digital circuitry which designers must be aware of, but there is one field in which the analogue and the digital are intricately meshed. Switch mode power supplies use digital techniques to exploit the analogue properties of components such as inductors and capacitors, and can be astoundingly clever in the way they do this to extract the last fraction of a percent efficiency from their conversion. Thus their design can be something of a Dark Art, so it’s always interesting to have a good read explaining some of the intricacies. [James Wilson] has built a flyback step-up converter to power Nixie tubes, and his write-up follows the whole process in great depth.

This type of converter seems at first glance to be a simple step-up design with a transformer that has a primary and secondary, where in fact it relies on the collapse in magnetic field during the off period of its duty cycle to provide a spike in voltage and thus a step-up beyond that you’d expect from the transformer alone. The write-up takes us through all this starting from a theoretical perspective, and then goes further into the realm of component selection and the effects of component properties on the waveforms involved. If you have ever battled ringing in a switch mode power supply you may recognise some of this.

If this field interests you, then there is probably no better place to send you for a start than Jim Williams’ 1987 app note 25 for Linear Technology: “Switching Regulators for Poets“.

Raspberry Pi Cluster Shows You The Ropes

April 24, 2020 by Bryan Cockfield 28 Comments

Raspberry Pi clusters are a common enough project, but a lot of the builds we see focus on the hardware side of the cluster. Once it’s up and running, though, what comes next? Raspberry Pis aren’t very powerful devices, but they can still be a great project for learning how to interact with a cluster of computers or for experimental test setups. In this project from [Dino], four Pis are networked together and then loaded with a basic set of software for cluster computing.

The first thing to set up, after the hardware and OS, is the network configuration. Each Pi needs a static IP in order to communicate properly. In this case, [Dino] makes extensive use of SSH. From there, he gets to work installing Prometheus and Grafana to use as monitoring software which can track system resources and operating temperature. After that, the final step is to install Ansible which is monitoring software specifically meant for clusters, which allows all of the computers to be administered more as a unit than as four separate devices.

This was only part 1 of [Dino]’s dive into cluster computing, and we hope there’s more to come. There’s a lot to do with a computer cluster, and once you learn the ropes with a Raspberry Pi setup like this it will be a lot easier to move on to a more powerful (and expensive) setup that can power through some serious work.

Odd Crosley Radios From The 1920s

April 24, 2020 by Al Williams 37 Comments

You may sometimes see the Crosley name today on cheap record players, but from what we can tell that company isn’t connected with the Crosley Radio company that was a powerhouse in the field from 1921 to 1956. [Uniservo] looks at two of the very early entries from Crosley: the model VIII and the XJ. You can see the video of both radios, below.

The company started by making car parts but grew rapidly and entered the radio business very successfully in 1921. We can only imagine what a non-technical person thought of these radios with all the knobs and switches, for some it must have been very intimidating.

Continue reading “Odd Crosley Radios From The 1920s” →

GPU Turned Into Radio Transmitter To Defeat Air-Gapped PC

April 24, 2020 by Dan Maloney 31 Comments

Another week, another exploit against an air-gapped computer. And this time, the attack is particularly clever and pernicious: turning a GPU into a radio transmitter.

The first part of [Mikhail Davidov] and [Baron Oldenburg]’s article is a review of some of the basics of exploring the RF emissions of computers using software-defined radio (SDR) dongles. Most readers can safely skip ahead a bit to section 9, which gets into the process they used to sniff for potentially compromising RF leaks from an air-gapped test computer. After finding a few weak signals in the gigahertz range and dismissing them as attack vectors due to their limited penetration potential, they settled in on the GPU card, a Radeon Pro WX3100, and specifically on the power management features of its ATI chipset.

With a GPU benchmarking program running, they switched the graphics card shader clock between its two lowest power settings, which produced a strong signal on the SDR waterfall at 428 MHz. They were able to receive this signal up to 50 feet (15 meters) away, perhaps to the annoyance of nearby hams as this is plunk in the middle of the 70-cm band. This is theoretically enough to exfiltrate data, but at a painfully low bitrate. So they improved the exploit by forcing the CPU driver to vary the shader clock frequency in one megahertz steps, allowing them to implement higher throughput encoding schemes. You can hear the change in signal caused by different graphics being displayed in the video below; one doesn’t need much imagination to see how malware could leverage this to exfiltrate pretty much anything on the computer.

It’s a fascinating hack, and hats off to [Davidov] and [Oldenburg] for revealing this weakness. We’ll have to throw this on the pile with all the other side-channel attacks [Samy Kamkar] covered in his 2019 Supercon talk.

Continue reading “GPU Turned Into Radio Transmitter To Defeat Air-Gapped PC” →