The Light Guide Hiding In Your Extrusion

There should be a line of jokes that start “A physicist and an engineer walk into a bar…”. In my case I’m an engineer and my housemate is a physicist, so random conversations sometimes take interesting turns. Take the other day for example, as one does when talking she picked up a piece of aluminium extrusion that was sitting on our coffee table and turned it over in her hands. It has a hole down its centre and it’s natural to peer down it, at which point her attention was caught by the appearance of a series of concentric rings of light. Our conversation turned to the mechanism which might be causing this, and along the way took us into cameras, waveguides, and optical fibres.

The light reaching us after traveling along a straight narrow tube should at a cursory glance be traveling in a straight line, and indeed when I point the extrusion out of my window and look down it I can see a small segment of the tree in the distance I’ve pointed it at. It didn’t take us long to conclude that the concentric rings were successive reflections of the light coming into the end hole from off-centre angles.

In effect, the extrusion is a pinhole camera in which the image is projected onto the inside of a cylinder stretching away from the pinhole rather than onto a flat piece of film, and we were seeing the successive reflections of the resulting distorted image as they bounced to and fro down the tube towards us. It’s likely the imperfect mirror formed by the aluminium wall allowed us to see each image, as light was being diffused in our direction. Adding a piece of tape with a small pinhole at the end accentuated this effect, with the circles becoming much more sharply defined as the projected image became less blurry. Continue reading “The Light Guide Hiding In Your Extrusion”

Screenshot of a 1988 news report on the Morris Worm computer virus

Retrotechtacular: Cheesy 1980s News Report On Early Internet Virus

It was a cold autumn night in 1988. The people of Cambridge, Massachusetts lay asleep in their beds unaware of the future horror about to be unleashed from the labs of the nearby college. It was a virus, but not just any virus. This virus was a computer program whose only mission was to infect every machine it could come in contact with. Just a few deft keystrokes is all that separated law abiding citizens from the…over the top reporting in this throwback news reel posted by [Kahvowa].

Computer History Museum exhibit of the floppy disk used to distribute the Morris worm computer virus.
Computer History Museum exhibit featuring the original floppy disk used to distribute the Morris Worm computer virus.

To be fair, the concept of a computer virus certainly warranted a bit of explanation for folks in the era of Miami Vice. The only places where people would likely run into multiple computers all hooked together was a bank or a college campus. MIT was the campus in question for this news report as it served as ground zero for the Morris Worm virus.

Named after its creator, Robert Tappan Morris, the Morris Worm was one of the first programs to replicate itself via vulnerabilities in networked computer systems. Its author intended the program to be a benign method of pointing out holes, however, it ended up copying itself onto systems multiple times to the point of crashing. Removing the virus from an infected machine often took multiple days, and the total damage of the virus was estimated to be in the millions of dollars.

In an attempt to anonymize himself, Morris initially launched his worm program from a computer lab at MIT as he was studying at Cornell at the time. It didn’t work. Morris would go onto to be the first person to receive a felony conviction under the 1986 Computer Fraud and Abuse Act. After the appeals process, he received a sentence a community service and a fine. After college Morris co-founded the online web store software company Viaweb that Yahoo! would acquire in 1998 for 49 million dollars. Years later in an ironic twist, Morris would return to academia as a professor at MIT’s department of Electrical Engineering and Computer Science.

Interested in some info on viruses of a different nature? Check out this brief history on viruses from last year.
Continue reading “Retrotechtacular: Cheesy 1980s News Report On Early Internet Virus”

Top side of the VL670 breakout board, with two USB connectors and the VL670 chip in the center.

A Chip To Bridge The USB 2 – USB 3 Divide

On Twitter, [whitequark] has  found and highlighted an intriguing design – a breakout board for the VL670, accompanied by an extensive yet very easy to digest write-up about its usefulness and inner workings. The VL670 is a chip that addresses a surprising problem – converting USB 2.0 signals into USB 3.0.

If you have a USB 2.0 device and a host with only USB 3.0 signals available, this chip is for you. It might be puzzling – why is this even needed? It’s about the little-known dark secret of USB3, that anyone can deduce if they ever have to deal with a 9-pin USB 3.0 connector where one of the three differential pairs doesn’t quite make contact.

When you see a blue “3.0” port, it’s actually USB 2 and USB 3 — two separate interfaces joined into a single connector. USB 3 uses two single-directional differential pairs, akin to PCI-E, whereas USB 2 uses a single bidirectional one, and the two interfaces on a blue connector operate basically independently of each other. There’s many implications to this that are counterintuitive if you simply take “USB 3.0” for “faster backwards-compatible USB”, and they have painful consequences.

For instance, USB 3 hub ICs have two separate hub entities inside – one for USB 3 and one for USB 2. Even if you have a USB 3 hub plugged into a USB 3 port, multiple USB 2 devices plugged into it still cannot break through the USB 2 uplink limit of 480 MBps. If you ever thought that a faster hub with a faster uplink would fix your USB 2 device speed problems – USB-IF engineers, apparently, thought differently; and you might have to find a workaround for your “many cheap SDRs and Pi 4 in a box” setup. Continue reading “A Chip To Bridge The USB 2 – USB 3 Divide”

Metal 3D Printing Hack Chat

Join us on Wednesday, March 9 at noon Pacific for the Metal 3D Printing Hack Chat with Agustin Cruz!

3D printing has been an enabling technology, and the ability to create parts that never existed anywhere before has been a real game-changer. But the cheap and readily accessible FDM and SLA printers we’ve come to depend on are not without their drawbacks, chief among which is that they only make plastic parts. Wouldn’t it be great if we home-gamers had the ability to print metal parts just like they do in industry? Agustin Cruz thinks so, and he’s been hard at work on an electron-beam sintering printer to make that dream come true. Dealing with the technical challenges of such a printer hasn’t been easy, but then again, squeezing out melted plastic wasn’t easy at first either.

join-hack-chatAgustin has agreed to take a little time out of his project to talk to us about his progress, and to share what he has learned about electron-beam printing. Along the way, we’ll talk about metal printing in general, and perhaps even take a look at where the whole field is going and how — and when — it’ll penetrate the hobby printing market.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, March 9 at 12:00 PM Pacific time. If time zones have you tied up, we have a handy time zone converter.
Continue reading “Metal 3D Printing Hack Chat”

Hackaday Links Column Banner

Hackaday Links: March 6, 2022

As if the war in Ukraine weren’t bad enough right here on Earth, it threatens knock-on effects that could be felt as far away as Mars. One victim of the deteriorating relationships between nations is the next phase of the ExoMars project, a joint ESA-Roscosmos mission that includes the Rosalind Franklin rover. The long-delayed mission was most recently set for launch in October 2022, but the ESA says that hitting the narrow launch window is now “very unlikely.” That’s a shame, since the orbital dynamics of Earth and Mars will mean that it’ll be 2024 before another Hohmann Transfer window opens. There are also going to be repercussions throughout the launch industry due to Russia pulling the Soyuz launch team out of the ESA’s spaceport in Guiana. And things have to be mighty tense aboard the ISS right about now, since the station requires periodic orbital boosting with Russian Progress rockets.

Continue reading “Hackaday Links: March 6, 2022”

Al Williams Tells All In The Logic Simulation Hack Chat

The list of requirements for hosting one of our weekly Hack Chats is pretty short: you’ve got to be knowledgeable, passionate, and above all else, willing to put those two quantities on display for a group of like-minded strangers. Beyond that, we’re not too picky. From industry insider to weekend hobbyist, high school dropout to double doctorate, if you’ve got something interesting to talk about, we’re ready to listen.

But in casting a such a wide net, we occasionally forget that we’ve got a considerable collection of potential hosts within our own worldwide roster of contributors. Among this cast of characters, few can boast the same incredible body of knowledge as Al Williams, who was able to pencil in some time this week to host the Logic Simulation Hack Chat.

Or at least, that was the idea. In reality the Chat covered a wide range of topics, and was peppered with fascinating anecdotes pulled from Al’s decades of experience in the field. Though to be fair, we expected no less. He was building hardware before many of us were born, and can take credit for designs that have been at the bottom of the ocean as well as launched into orbit. He’s been writing about it just as long too, with articles of his appearing in iconic print magazines such as Dr. Dobb’s Journal.

Al has seen and done so much that he still surprises us with the occasional nugget, and we’ve been working with him for years. It was only a week or two back that he started a story with “Back when I used to manage a gas pipeline…” in the middle of a conversation about utility metering.

Of course, that’s not to say some technical discussion didn’t sneak in there from time to time. Sure Al’s  recollection of how they used to literally crawl over the schematics for the 68000 back at Motorola might stick out as a particular high point, but he also explains his personal preference for vendor-specific software tools over their more generic open source counterparts. He also draws comparisons between hardware description languages (HDLs) like Verilog and parametric CAD tools such as OpenSCAD in the way that they help model complex relationships in ways that can’t be easily done by more traditional means.

At one point the conversation lingers on the design and production of application-specific integrated circuits (ASICs), and how they compare to field-programmable gate arrays (FPGAs). Traditionally ASICs have been out of reach for the hobbyist, but with the recent collaboration between Google and SkyWater Technology to create an open source process design kit (PDK), they’re now within the capabilities of a dedicated individual. Matt Venn spoke on the topic during Remoticon 2021, and it’s good to see more folks in the community openly discussing the possibilities of custom silicon designed by hackers.

From there, things start really getting wild. From dreaming of virtual reality circuit simulators that let you fly amongst your creations like in Tron, to salivating over high-end technologies such as reflective memory, this Chat really runs the gamut. But then, that’s sort of why we hold them in the first place. Whether you actively participate or are just along for the ride, the Hack Chat gives everyone in the community a chance to gather around a virtual water cooler with fascinating characters that you won’t find anywhere else.


The Hack Chat is a weekly online chat session hosted by leading experts from all corners of the hardware hacking universe. It’s a great way for hackers connect in a fun and informal way, but if you can’t make it live, these overview posts as well as the transcripts posted to Hackaday.io make sure you don’t miss out.

Hackaday Podcast 158: Phased Array Physics, CRTs Two Ways, A Micro Microcontroller, And A Surgically Implanted Red Herring

Join Editor-in-Chief Elliot Williams and Staff Writer Dan Maloney as they take a look at the week’s top stories, taken straight off the pages of Hackaday. What happens when you stuff modern parts into a 90’s novelty PC case? Nothing good, but everything awesome! Is there any way to prevent PCB soil moisture sensors from being destroyed by, you know, soil moisture? How small is too small for a microcontroller, and who needs documentation anyway? We also cast a jaundiced eye — err, ear — at an electronic cheating scandal, and if you’ve ever wondered how phased arrays and beam steering work, gazing into a pan of water might just answer your questions. We also share all our soldering war stories, and hey — what’s with all these CRT projects anyway?

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct Download (52 MB, but sounds like at least 58 MB!)

Continue reading “Hackaday Podcast 158: Phased Array Physics, CRTs Two Ways, A Micro Microcontroller, And A Surgically Implanted Red Herring”