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At Hackaday, we’re tapped into Hacker Culture. This goes far beyond a choice of operating system (Arch Linux, or more correctly, ‘Arch GNU/Linux’, or as I’ve recently taken to calling it, ‘Arch GNU plus Linux’). This culture infects every fiber of our soul, from music (DEF CON’s station on Soma FM), our choice in outerwear (black hoodies, duh), and our choice in laptops (covered in stickers). We all wear uniforms, although a gaggle of computer science and electronics nerds all wearing black t-shirts won’t tell you that. We all conform, whether we’re aware of it or not.
Despite a standardized uniform for this subculture, one small detail of this Hacker Uniform has remained unresolved for decades. Are one-hole or three-hole balaclavas best for hacking? Which balaclava is best for stealing bank accounts and hacking into NASA computers? What offers the best protection from precipitating ones and zeros in a real-life Matrix screensaver?
I have a bit of a love/hate relationship with the Arduino. But if I had two serious gripes about the original offering it was the 8-bit CPU and the lack of proper debugging support. Now there’s plenty of 32-bit support in the Arduino IDE, so that takes care of the first big issue. Taking care of having a real debugger, though, is a bit trickier. I recently set out to use one of the cheap “blue pill” STM32 ARM boards. These are available for just a few bucks from the usual Chinese sources. I picked mine up for about $6 because I wanted it in a week instead of a month. That’s still pretty inexpensive. The chip has a lot of great debugging features. Can we unlock them? You can, if you have the right approach.
The Part
For a few bucks, you can’t complain about the hardware. The STM32F103C8T6 onboard is a Cortex-M3 processor that runs at 72 MHz. There’s 64K of flash and 20K of RAM. There’s a minimicro-USB that can act as a programming port (but not at first). There’s also many 5 V-tolerant pins, even though this a 3.3 V part.
You can find a lot more information on this wiki. The board is a clone–more or less–of a Maple Mini. In fact, that’s one way you can use these. You can use the serial or ST-Link port to program the Maple bootloader (all open source) and use it like a Maple. That is, you can program it via the USB cable.
From my point of view, though, I don’t want to try to debugging over the serial port and if I have the ST-Link port already set up, I don’t care about a bootloader. You can get hardware that acts as a USB to ST-Link device inexpensively, but I happen to have an STM32VLDISCOVER board hanging around. Most of the STM32 demo boards have an ST-Link programmer onboard that is made to use without the original target hardware. On some of the older boards, you had to cut traces, but most of the new ones just have two jumpers you remove when you want to use the programmer to drive another device.
The “blue pill” designation is just a common nickname referring to the Matrix, not the pharmaceuticals you see on TV ads. The board has four pins at one edge to accommodate the ST-Link interface. The pin ordering didn’t match up with the four pins on the STM32VLDISCOVER, so you can’t just use a straight four-pin cable. You also need to bring power over to the board since it will have to power the programmer, too. I took the power from the STM32VLDISCOVER board (which is getting its power from USB) and jumpered it to my breadboard since that was handy.
Join [Jørgen Kragh Jakobsen], Analog/digital Design Engineer at Merus-Audio, for this week’s Hack Chat.
Every week, we find a few interesting people making the things that make the things that make all the things, sit them down in front of a computer, and get them to spill the beans on how modern manufacturing and technology actually happens. This is the Hack Chat, and it’s happening this Friday, March 31, at noon PDT (20:00 UTC).
Jørgen’s company has developed a line of multi level Class D amplifiers that focus on power reduction to save battery life in mobile application without losing audio quality.
There are a lot of tricks to bring down power consumption, some on core technologies on transistor switching, others based on input level where modulation type and frequency is dynamically changed to fit everything from background audio level to party mode.
Here’s How To Take Part:
Our Hack Chats are live community events on the Hackaday.io Hack Chat group messaging.
Log into Hackaday.io, visit that page, and look for the ‘Join this Project’ Button. Once you’re part of the project, the button will change to ‘Team Messaging’, which takes you directly to the Hack Chat.
You don’t have to wait until Friday; join whenever you want and you can see what the community is talking about.
Upcoming Hack Chats
We’ve got a lot on the table when it comes to our Hack Chats. On April 7th, our host will be [Samy Kamkar], hacker extraordinaire, to talk reverse engineering.
In the last edition of Don’t Fear the Filter, we built up two examples of the simplest and most-used active filter of all time: the two-pole Sallen-Key lowpass. This time, we’re going to put two of these basic filter blocks in a row, and end up with a much sharper lowpass filter as well as a bandpass filter. For the bandpass, we’ll need to build up a quick highpass filter as well. Bonus!
I claimed last time that the Sallen-Key lowpass would cover something like 80% of your filtering needs. (And 72.4% of all statistics are totally made up!) These two will probably get you through another 10% or so. Honestly, I’ve never built a standalone active highpass, for reasons we’ll see below, but the active bandpass filter that we’re building it for is a great tool to have in your belt, especially for anything audio.
The 20th century saw some amazing technological developments. We went from airplanes to the moon. We went from slide rules to digital computers. Crank telephones to cell phones. But two of the most amazing feats of that era were ones that non-technical people probably hardly think about. The transformation of radio and TV from mono and black and white, to stereo and color. What was interesting about both of these is that engineers managed to find a way to push the new better result into the same form as the old version and — this is the amazing part — do it in such a way that the old technology still worked. Maybe it is the rate that new technology moves today, but we aren’t doing that today. Digital TV required all-new everything: transmitters, receivers, frequencies, and recording gear. Good luck trying to play the latest video game on your 25-year-old PC.
It is hard to remember when stores were full of all sorts of audio and video media. We’ve noticed that all forms of media are starting to vanish. Everything audio and video are all streamed or downloaded these days. Records, 8-tracks, cassettes, and even CDs and DVDs are vanishing. However, vinyl records have made a come back in the last few years for their novelty or nostalgic value.
The VCF East is the largest gathering of retrocomputing aficionados on the east coast. It’s three days of talks, exhibits, a flea market, and a pow-wow of the greatest minds buried under obsolete technology. No VCF is complete without a few talks, and this year is shaping up to be great. Keynotes will include [Bjarne Stroustrup], designer / implementor / inventor of C++. Computer historian [Bill Degnan] will give a review of 40 years of ‘appliance computers’, and [Tom Perera], Ph.D. will be giving a talk on the Enigma machine.
The exhibits at VCF are always the star of the show, and this year is no different. Highlights include mechanical computers, the finest from Silicon Graphics, and a version of Unix published by Microsoft. The individual exhibits are always great; last year the world’s first digital camera made an appearance. If you’re in the area, this isn’t an event to miss. VCF is going down at InfoAge, a science center at the former Camp Evans — a military installation that is best described as, ‘DARPA before World War II’.
Hackaday is proud to once again sponsor VCF East. This has been going on for a couple of years now and our Art Director, [Joe Kim] has created some incredible art as part of the sponsorship. Click on the thumbnail of this year’s art to embiggen. The VCF West art from last year is a stunning take on the Macintosh and last year’s VCF East art reflected the retro hackathon we sponsored.
The nuclear age changed steel, and for decades we had to pay the price for it. The first tests of the atomic bomb were a milestone in many ways, and have left a mark in history and in the surface of the Earth. The level of background radiation in the air increased, and this had an effect on the production of steel, so that steel produced since 1945 has had elevated levels of radioactivity. This can be a problem for sensitive instruments, so there was a demand for steel called low background steel, which was made before the trinity tests.
The Bessemer process pumps air through the iron to remove impurities. shropshirehistory.com
The production of steel is done with the Bessemer process, which takes the molten pig iron and blasts air through it. By pumping air through the steel, the oxygen reacts with impurities and oxidizes, and the impurities are drawn out either as gas or slag, which is then skimmed off. The problem is that the atmospheric air has radioactive impurities of its own, which are deposited into the steel, yielding a slightly radioactive material. Since the late 1960s steel production uses a slightly modified technique called the BOS, or Basic Oxygen Steelmaking, in which pure oxygen is pumped through the iron. This is better, but radioactive material can still slip through. In particular, we’re interested in cobalt, which dissolves very easily in steel, so it isn’t as affected by the Bessemer or BOS methods. Sometimes cobalt is intentionally added to steel, though not the radioactive isotope, and only for very specialized purposes.
Recycling is another reason that modern steel stays radioactive. We’ve been great about recycling steel, but the downside is that some of those impurities stick around.
Why Do We Need Low Background Steel?
Imagine you have a sensor that needs to be extremely sensitive to low levels of radiation. This could be Geiger counters, medical devices, or vehicles destined for space exploration. If they have a container that is slightly radioactive it creates an unacceptable noise floor. That’s where Low Background Steel comes in.
A person is placed into a low background steel container with sensitive equipment to measure the radioactivity of the body, which may be near the background level. Photo from orau.org
So where do you get steel, which is a man-made material, that was made before 1945? Primarily from the ocean, in sunken ships from WWII. They weren’t exposed to the atomic age air when they were made, and haven’t been recycled and mixed with newer radioactive steel. We literally cut the ships apart underwater, scrape off the barnacles, and reuse the steel.
Fortunately, this is a problem that’s going away on its own, so the headline is really only appropriate as a great reference to a popular movie. After 1975, testing moved underground, reducing, but not eliminating, the amount of radiation pumped into the air. Since various treaties ending the testing of nuclear weapons, and thanks to the short half-life of some of the radioactive isotopes, the background radiation in the air has been decreasing. Cobalt-60 has a half-life of 5.26 years, which means that steel is getting less and less radioactive on its own (Cobalt-60 from 1945 would now be at .008% of original levels). The newer BOS technique exposes the steel to fewer impurities from the air, too. Eventually the need for special low background steel will be just a memory.
Oddly enough, steel isn’t the only thing that we’ve dragged from the bottom of the ocean. Ancient Roman lead has also had a part in modern sensing.
Fortunately, this is a problem that’s going away on its own, so the headline is really only appropriate as a great reference to a 
