Theremin’s Bug: How The Soviet Union Spied On The US Embassy For 7 Years

December 8, 2015 by Adam Fabio 175 Comments

The man leaned over his creation, carefully assembling the tiny pieces. This was the hardest part, placing a thin silver plated diaphragm over the internal chamber. The diaphragm had to be strong enough to support itself, yet flexible enough to be affected by the slightest sound. One false move, and the device would be ruined. To fail meant a return to the road work detail, quite possibly a death sentence. Finally, the job was done. The man leaned back to admire his work.

The man in this semi-fictional vignette was Lev Sergeyevich Termen, better known in the western world as Léon Theremin. You know Theremin for the musical instrument which bears his name. In the spy business though, he is known as the creator of one of the most successful clandestine listening devices ever used against the American government.

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The Death Of Surplus

December 7, 2015 by Brandon Dunson 148 Comments

I thought the surplus electronics market in Dallas was a byproduct of local manufacturing, after all we have some heavy hitters in our back yard: Texas Instruments, Maxim (Dallas Semiconductor), ST Micro (at one time), Diodes Incorporated. If we widen our radius to include Austin (3 hours down the road) we can make a much more impressive list by including: National Instruments, Freescale Semiconductor, better yet I’ll just insert the graphic I’m pulling data from right here:

texas_companies_map — Texas Electronics Map Source: Texas.gov

Granted, not all of these are companies that manufacture silicon, or even have manufacturing facilities here in Texas. That doesn’t necessarily matter for surplus to exist. Back to my point of where surplus originated. While I wasn’t completely wrong (these companies certainly have helped contribute to the surplus electronics market) the beginnings of surplus storefronts date back to World War II. Did anyone see that coming? Neither did I. However it does make sense, the US government would have had a large stock of “stuff” to get rid of at the end of the war.

Enter the sale of government surplus all over the nation, usually near air force bases. So this is how the more generalized concept of a surplus shop came to be in existence; mix in the domestic manufacturing of electronics in the 1970’s and we have electronics surplus shops aplenty.

My First Hand Experience

I didn’t really appreciate how valuable my local electronics shop was until watching Beers in Bunnie’s Workshop – Workshop Video #36. If you haven’t seen the video you only need to know that [Ian] of Dangerous Prototypes and [bunnie] of Andrew [bunnie] Huang are standing in [bunnie]s work-space in Singapore drinking beer and talking about the lab that is [bunnie]s life. You with me now? Okay, there is a point in the video where the two discuss the ability to run down the street and buy a connector as something only available in Singapore or Shenzhen. Let me briefly pause here to clarify that I’m not comparing my local electronics shop to the Shenzhen market or Sim Lim Tower in Singapore, only stating that I too can hold parts in-hand before purchasing them. I’m also not [brandon] of Dangerous Prototypes or Andrew [brandon] Huang, clearly.

I do however have an electronics selection at my disposal that is unmatched until you get to the west coast shops. I went on a bit of an adventure with the owner [Jim Tanner] of my local shop [Tanner Electronics] to take some pictures of the retail floor and a few behind the scenes (warehouse) shots that you can check out after the break.

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Experiences In Developing An Electronics Kit

December 5, 2015 by Brian Benchoff 12 Comments

This year’s Hackaday Prize included a category for the Best Product, and there is perhaps no project that has inspired more people to throw money at their computer screens than [Oscar Vermeulen]’s PiDP-8/I. It’s a replica of the PDP-8/I from 1968. Instead of discrete electronics driving the blinkenlights and switches on the front of this computer, [Oscar]’s version uses a Raspberry Pi and the incredible SIMH emulator for dozens of old mainframes and minicomputers. It is, for all intents and purposes, a miniaturized version of a 50 year old computer that will fit on your desk and is powered by a phone charger.

Check out the video of [Oscar]’s talk below then join us after the break for more discussion of his work.

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A Teensy Logic Analyzer For A 6502

December 4, 2015 by Brian Benchoff 11 Comments

[John] has an interesting, if old piece of tech sitting on his workbench. It’s an Ohio Scientific C3-8P computer from the late 70s by way of a few garages, basements, and attics. As with most tech of this vintage, there are some problems, and [John] found debugging a little frustrating without the ability to trace and watch the programs. He needed a logic analyzer, and found one in an unlikely piece of hardware. [John] built one using a Teensy microcontroller, and further refinement of this project could turn it into a full in-system emulator.

The old Ohio Scientific computer [John] is trying to bring back from the dead is based on the 6502 CPU. That’s sixteen address lines to monitor, eight data lines, and four control lines. These were wired directly to a Teensy 3.1.

Reading and controlling all the signals from a 6502 is a task that falls to Linux. A command line program controls the Teensy and is capable of reading memory, setting trigger addresses, dumping the entire address space to a file, or just recording the last 5,000 clock cycles. This kind of tech existed back in the late 70s and early 80s. It also cost a fortune. Now, with a $20 Teensy and probably another $30 in ribbon cables and test clips, anyone can build a logic analyser for a very old computer system.

Videos below.

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Retrocomputing On A Chip

December 3, 2015 by Mike Szczys 10 Comments

New electrical components enable us to reconstruct old wiring more efficiently. Especially, the accessible and cheap FPGA kits which offer the possibility to put together wiring of many old computers as an “on-a-chip” solution.

When I managed to get a hold of an old bubble LED display and a pretty mechanical matrix keyboard, I decided to build a replica of an old single board computer. Logical options seemed to be to build either KIM-1 or Heathkit ET-3400. Replicas of KIM-1 already exist, even for Arduino, so my task would be reduced to connect the keyboard and display. But then I told myself that I would use the fact that my bubble display has 9 positions as an excuse to build the legendary Czechoslovak Single Board Computer PMI-80 which used the same display. My replica is an FPGA, or rather an FPGA emulator of this very computer.

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Nuts About Volts

December 3, 2015 by Nava Whiteford 30 Comments

Among multimeters one instrument stands far and above the rest. An object desired for its accuracy, resolution and shear engineering beauty. I speak of course of the HP 3458A. That’s right, not Keysight, not even Agilent (though of course it goes by those brands too). The 3458A was released in 1989, when HP was still… well… HP. An elegant meter from a more civilized age. As the HP Journal documents, the 3458A was a significant engineering feat and has remained in production (and largely unchallenged) for the last 26 years.

But what, you might ask, makes the 3458A such a significant and desirable instrument? It’s all in the digits. The 3458A is one of the few 8.5 digit multimeters available. It is therefore sensitive to microvolt deflections on 10 volt measurements. It is this ability to distinguished tiny changes on large signals that sets high precision multimeters apart. Imagine weighing an elephant and being able to count the number of flies that land on its back by the change in weight. The 3458A accomplishes a similar feat.

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Sit ‘n Spin For Big Kids

November 28, 2015 by Adam Fabio 16 Comments

Humans seem to have a strange love affair with testing their limits, especially when it comes to spinning. Perhaps they ride the Gravitron while dreaming they’re in NASA’s 20 g test centrifuge. When carnival rides aren’t enough though, a few intrepid hackers bust out the welders and take matters into their own hands. This is a hack that goes by many names, though “The Redneck Spin Chair” will bring up plenty of hits on YouTube.

The design is dead simple. Take a rear differential and axle assembly out of an old car or truck. Rotate it 90 degrees, so the diff is now pointing up. Weld a chair on. Finally, weld on a couple of tow bars. Pulling the whole mess will cause the wheels to spin, which transmits power through the differential and rotates the chair. The ride doesn’t have be pulled very fast, as automotive differentials generally have reduction between 3:1 and 5:1. We’re running things in reverse, so that reduction becomes a multiplier. The result, which can be seen in the video below is a very dizzy rider.

The earliest incarnation of this ride we could find was created at Eagle Mountain in Burtrum, Minnesota. We’re betting this particular hack has been around for decades longer though. The closest in our recent memory is North Street Labs’ Centrifury. Do you know of an earlier incarnation? Let us know in the comments!

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