3D Printing Antennas With Dielectric Resin

February 21, 2023 by 14 Comments

[Machining and Microwaves] has long wanted to use a 3D printer to print RF components for antennas and microwave lenses. He heard that Rogers — the company known for making PCB substrates, among other things — had a dielectric resin available and asked them if he could try some. They agreed, with some stipulations, including that he had to visit their facility and show his designs in a video. Because of that, the video seems a little bit like a commercial, but we think he is genuinely excited about the possibility of the resin.

Since he was in their facility, he was able to interview several of the people behind the resin, and they had some interesting observations about keeping resin consistent during printing and how the moonbounce feed he wanted to print would work.

Some of the exotic RF test equipment was interesting to see, too. The microwave lenses look like some kind of modern art. According to the Roger’s website:

Radix Printable Dielectric materials are a ceramic-filled, UV-curable polymer designed for use with photopolymer 3D-printing processes like sterolithography (SLA) and digital light processing (DLP) printing. These materials and printing processes enable the use of high-resolution, scalable 3D-printing for complex RF dielectric components such as gradient index (GRIN) lenses or three-dimensional circuits. The 2.8Dk printable dielectric is designed to have low loss characteristics through millimeter wave (mmWave) frequencies and low moisture absorption for end-use applications.

It isn’t clear to us that you could use this resin in your own printers, but they did look pretty similar to what we have hanging around except, perhaps, for the continuous circulation of the resin pool. We figured the resin wasn’t inexpensive. In fact, we found a liter online for $1,863. We don’t know if that’s the suggested retail price or not, but we also suppose if you need this material, you won’t be that surprised at the cost.

If you don’t need microwave frequencies, you might be able to get by with some easier techniques. Or, you can even do something slightly more difficult but probably a lot cheaper.

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SUPERCON 2022: Kuba Tyszko Cracks Encrypted Software

February 21, 2023 by 5 Comments

[Kuba Tyszko] like many of us, has been hacking things from a young age. An early attempt at hacking around with grandpa’s tractor might have been swiftly quashed by his father, but likely this was not the last such incident. With a more recent interest in cracking encrypted applications, [Kuba] gives us some insights into some of the tools at your disposal for reading out the encrypted secrets of applications that have something worth hiding.  (Slides here, PDF.)

There may be all sorts of reasons for such applications to have an encrypted portion, and that’s not really the focus. One such application that [Kuba] describes was a pre-trained machine-learning model written in the R scripting language. If you’re not familiar with R, it is commonly used for ‘data science’ type tasks and has a big fan base. It’s worth checking out. Anyway, the application binary took two command line arguments, one was the encrypted blob of the model, and the second was the path to the test data set for model verification.

The first thing [Kuba] suggests is to disable network access, just in case the application wants to ‘dial home.’ We don’t want that. The application was intended for Linux, so the first port of call was to see what libraries it was linked against using the ldd command. This indicated that it was linked against OpenSSL, so that was a likely candidate for encryption support. Next up, running objdump gave some clues as to the various components of the binary. It was determined that it was doing something with 256-bit AES encryption. Now after applying a little experience (or educated guesswork, if you prefer), the likely scenario is that the binary yanks the private key from somewhere within itself reads the encrypted blob file, and passes this over to libssl. Then the plaintext R script is passed off to the R runtime, the model executes against the test data, and results are collated.

[Kuba]’s first attack method was to grab the OpenSSL source code and drop in some strategic printf() function calls into the target functions. Next, using the LD_PRELOAD ‘trick’ the standard system OpenSSL library was substituted with the ‘fake’ version with the trojan printfs. The result of this was the decryption function gleefully sending the plaintext R script direct to the terminal. No need to even locate the private key!

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New Product: The Raspberry Pi Debug Probe

February 21, 2023 by 35 Comments

It’s fair to say that among the new product launches we see all the time, anything new from the folks at Raspberry Pi claims our attention. It’s not that their signature Linux single-board computers (SBCs) are necessarily the best or the fastest hardware on paper, but that they’re the ones with meaningful decade-plus support. Add to that their RP2040 microcontroller and its associated Pico boards, and they’re the one to watch.

Today we’ve got news of a new Pi, not a general purpose computer, but useful nevertheless. The Raspberry Pi Debug Probe is a small RP2040-based board that provides a SWD interface for debugging any ARM microcontroller as well as a more generic USB to UART interface.

The article sums up nicely what this board does — it’s for bare metal ARM coders, and it uses ARM’s built-in debugging infrastructure. It’s something that away from Hackaday we’ve seen friends using the 2040 for as one of the few readily available chips in the shortage, and it’s thus extremely convenient to have readily available as a product.

So if you’re a high level programmer it’s not essential, but if you’re really getting down to the nuts-and-bolts of an ARM microcontroller then you’ll want one of these. Of course, it’s by no means the first SWD interface we’ve seen, here’s one using an ESP32.

Exploring The History Of EPROM In The Soviet Union

February 21, 2023 by 17 Comments

An article on the history of EPROMs in the Soviet Union by [Vladimir Yakovlev] over at The CPU Shack Museum caught our attention. It is part one of a series on the topic, and walks you through the earliest Soviet EPROMs families.

Early EPROM programmer using punched paper tape (Intel, Electronics Magazine 1971)

The first of which, from the 1970s, is the K505RR1 developed and manufactured in Kyiv, equivalent to the first-generation Intel 1702A. It could hold 2048 bits, organized as 256×8, and offered a whopping 20 reprogramming cycles and data retention of 5000 hours.

The narrative proceeds to introduce several subsequent generations, design facilities, manufacturing techniques, and representative chip examples. A few tidbits — unlike Western EPROMs, the Soviets managed to put quartz windows in plastic packages (see the KP573 family).

In addition to the common gray or white, they also used different terracotta colored ceramic packages. An odd ceramic flat-pack EPROM is shown, and also some EPROMs whose dies have been painted over and re-badged as OTP chips.

Intel began producing EPROMs in 1971 as reported by the inventor, Intel’s Dov Frohman-Bentchkowsky, in Electronics Magazine’s 10 May edition (pg 91). We learned, amongst other things, that the 1701 did not have a quartz window, but could still be erased by exposure to X-rays. A friendly word of warning — browsing electronics advertisements from 50 years ago can easily consume your entire morning.

Once the package is sealed, information can still be erased by exposing it to X radiation in excess of 5×104 rads, a dose which is easily attainable with commercial X-ray generators.

To dig deeper, check out the CPU Shack’s write-up on the history of EPROMs in general, and a piece we wrote in 2014 about the history of home computers behind the Iron Curtain.

Tidy Breadboard Uses Banana Bread

February 20, 2023 by 21 Comments

Self-described passionate maker in the electronics and 3D printing world, [Jakob], aka [testudor], was getting frustrated trying to connect banana plugs to solderless breadboards. Project Banana Bread was born — small banana jack adaptors and a companion tray with pockets to hold up to six modules.

The base in the photo is made from 5083 aluminum, machined on a homemade CNC router. But design files for a yet-to-be-tested 3D printer version are available as well. As can happen, he strayed from the original goal of solving the banana jack issue, and also cranked out a USB-serial port and a blank template module for any custom interfaces folks may want to implement.

If it is only power connections you are interested in, we covered the Open Power project back in 2019. And also don’t forget the mother of all breadboards, this 1960s behemoth we wrote about last year. What kinds of breadboard interface modules do you find most useful? Let us know in the comments below.

 

Digital Library Of Amateur Radio And Communications Is A Treasure Trove

February 20, 2023 by 24 Comments

Having a big bookshelf of ham radio books and magazines used to be a point of bragging right for hams. These days, you are more likely to just browse the internet for information. But you can still have, virtually, that big shelf of old ham books, thanks to the DLARC — the digital library of Amateur Radio and Communications.

A grant from a private foundation has enable the Internet Archive to scan and index a trove of ham radio publications, including the old Callbooks, 73 Magazine, several ham radio group’s newsletters from around the globe, Radio Craft, and manuals from Icom, Kenwood, Yaesu, and others.

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Clear PLA Diffuses LEDs

February 20, 2023 by 11 Comments

[Chuck] often prints up interesting 3D prints. But we enjoyed his enhancement to a cheap LED Christmas tree kit. The original kit was simply a few green PCBs in the shape of a tree. Cute, but not really something a non-nerd would appreciate. What [Chuck] did, though, is printed a clear PLA overcoat for it and it came out great. You can see how great in the video below.

You might think transparent PLA would be really clear, but because of the layers, it is more translucent than transparent. For an LED diffuser, though, it works great. There are a few things to consider when printing for this purpose. First, you’d think vase mode would be perfect for this, but he found out it didn’t work well — possibly due to something in the model, which was a download from Thingiverse.

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