Sneakers: A Love-Fest

“A TURNIP CURES ELVIS” begins the opening credits, an intriguing beginning to a smart and still timely film that was released around 25 years ago. If you’ve never seen the movie, I’m about to spoil the hell out of it.

Sneakers features the title characters, hackers who work the 1992 gig economy as freelance penetration testers. They work for Martin Bishop, a hippie hacker Obi Wan who works San Francisco’s gray market, doing good deeds and helping banks improve their security.

While there is a fair amount of cheese in Sneakers, a lot of the problems the characters face — physical security and cryptography come to mind — remain the problems of today. Securing our digital business? Check. Surveillance? Check? Gray operators? Absolutely. At the same time, the movie does a good job of exploring different categories of hacker. The various characters seem to offer glimpses of people I see all the time at the hackerspace. Bigger than life, certainly, but they are in a Hollywood movie, after all.

Finally, the movie is just smart. Those opening credits offer a preview: the anagrams that begin the movie (“A TURNIP KILLS ELVIS” translates to Universal Pictures) are not just some art director’s conceit for the opening credits. The anagrams end up being important later on in the film, where there is a key clue hidden but if you think about it, shuffling letters on your Scrabble tray could be taken as a metaphor for hacker thinking — taking the same information as everyone else but looking at it in a different way.

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Piezomagnetic Trick Shrinks 2.5 GHz Antennas

To a ham radio operator used to “short”-wave antennas with lengths listed in tens of meters, the tiny antennas used in the gigahertz bands barely even register. But if your goal is making radio electronics that’s small enough to swallow, an antenna of a few centimeters is too big. Physics determines plausible antenna sizes, and there’s no way around that, but a large group of researchers and engineers have found a way of side-stepping the problem: resonating a nano-antenna acoustically instead of electromagnetically.

Normal antennas are tuned to some extent to the frequency that you want to pick up. Since the wavelength of a 2.5 GHz electromagnetic wave in free space is 120 cm mm, most practical antennas need a wire in the 12-60 cm mm range to bounce signals back and forth. The trick in the paper is to use a special piezomagnetic material as the antenna. Incoming radio waves get quickly turned into acoustic waves — physical movement in the nano-crystals. Since these sound waves travel a lot slower than the speed of light, they resonate off the walls of the crystal over a much shorter distance. A piezoelectric film layer turns these vibrations back into electrical signals.

Ceramic chip antennas use a similar trick. There, electromagnetic waves are slowed down inside the high-permittivity ceramic. But chip antennas are just slowing down EM waves, whereas the research demonstrated here is converting the EM to sound waves, which travel many orders of magnitude slower. Nice trick.

Granted, significant material science derring-do makes this possible, and you’re not going to be fabricating your own nanoscale piezomagnetic antennas any time soon, but with everything but the antenna getting nano-ified, it’s exciting to think of a future where the antennas can be baked directly into the IC.

Thanks [Ostracus] for the tip in the comments of this post on antenna basics. Via [Science Magazine].

The 1980s Called – Asking For The Z80 Membership Card

The ’80’s and early ’90’s saw a huge proliferation of “personal” computers, spawning an army of hacker kids who would go on to hone their computing chops on 8-bit and 16-bit computers from brands such as Sinclair, Commodore, Acorn, Apple, Atari, Tandy/RadioShack and Texas Instruments. Fast forward to 2017, and Raspberry-Pi, BeagleBone and micro:bit computers reign supreme. But the old 8-bit and 16-bit computer systems can still teach us a lot.

[Lee Hart] has built the amazing Z80 Membership Card — a Z80 computer that fits in an Altoids tin. His design uses generic through hole parts mounted on a PCB with large pads, thick tracks and lots of track clearances, making assembly easy. Add to this his detailed documentation, where he weaves some amazing story telling, and it makes for a really enjoyable, nostalgic build. It makes you want to get under the hood and learn about computers all over again. The Z80 Membership Card features a Zilog Z80 microprocessor running at 4 MHz with 32k RAM and 32K EPROM, loaded with BASIC interpreter and monitor programs. A pair of 30-pin headers provide connections to power, I/O pins, data, address and control signals.

To accompany this board, he’s built a couple of companion “shield” boards. The Front Panel Card has a 16-key hex pad, 7-digit 7-segment LED display and Serial port. [Lee] has packed in a ton of features on the custom monitor ROM for the front panel card making it a versatile, two board, 8-bit system. Recently, he finished testing a third board in this series — a Serial/SD-Card/RAM shield which adds bank-switchable RAM and SD-card interface to provide “disk” storage. He’s managed to run a full CP/M-80 operating system on it using 64k of RAM. The two-board stack fits nicely in a regular Altoids tin. A fellow hacker who built the three-board sandwich found it too tall for the Altoids tin, and shared the design for a 3D printable enclosure.

[Lee] provides detailed documentation about the project on his blog with schematics, assembly instructions and code. He’s happy to answer questions from anyone who wants help building this computer. Do check out all of his other projects, a couple of which we’ve covered in the past. Check out Lee Hart’s Membership Card — a similar Altoids tin sized tribute to the 1802 CMOS chip and how he’s Anthropomorphizing Microprocessors.

Finally, we have to stress this once again — check out his Assembly Manuals [PDF, exhibit #1] — they are amazingly entertaining.

Thanks to [Matthew Kelley] who grabbed one of [Lee]’s kits and then tipped us off.