Vintage Pro Audio Hack Chat

May 23, 2022 by 5 Comments

Join us on Wednesday, May 25 at noon Pacific for the Vintage Audio Hack Chat with Frank Olson!

There was a time, and not all that long ago on the cosmic scale, that if you wanted to hear music, you either needed to make it yourself or hire someone to do it for you. For most of history, music was very much a here and now thing, and when the song was over, that was it.

Thankfully, those days are long gone, and for better or worse, we have instant access to whatever music we’re in the mood for. The Spotify client in your pocket is a far cry from the iPod of a few years back, or the Walkman of the 80s, or even a mid-century transistor radio. But no matter how you listen to your music, it all starts with getting the live music recorded, and that’s where we’ll be going with this Hack Chat.

join-hack-chatHooking up the preamps, mixers, mics, and recorders that make modern music possible is what Frank Olson is all about. You’ll probably recognize Frank’s name from his unique niche as a maker of wooden microphones, but dig a little deeper and he’s got a lot of experience with vintage pro audio gear. As both a musician and an audio engineer, Frank brings an enthusiast’s passion for recording gear to the Hack Chat, and we’re looking forward to picking his brain on the unique ways he’s found to turn sounds into music and to get to all down on tape.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, May 25 at 12:00 PM Pacific time. If time zones have you tied up, we have a handy time zone converter.

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An Illuminating Look At A Wolf 5151 Light Source

May 23, 2022 by 6 Comments

While originally designed to put light where the sun don’t shine for medical purposes, [Nava Whiteford] says the Wolf 5151 Xenon endoscopic light source also works well for microscopy and general optical experiments, especially since you can get them fairly cheap on the second hand market. His cost just $50 USD, which is a steal when you consider a replacement for its 300 watt Olympus-made bulb will run you about 200 bucks alone.

That said, [Nava] recently moved on to a more compact light source, and figured that was a good enough excuse to crack open the Wolf 5151 and see what makes it tick. In this particular post he’s just looking at the optical side of things, which is arguably the most interesting aspect of the device. Helpfully, the whole assembly is mounted to its own sled of sorts that can be pulled from the light source for a closer examination.

A Steampunk dimmer switch.

Beyond that expensive bulb we mentioned earlier, there’s a thick piece of what appears to be standard plate glass being used as an IR and UV filter. [Nava] suspects this component is responsible for keeping the rest of the optics from overheating, which is backed up by the fact that the metal plate its mounted to appears to feature a K-type thermocouple to keep an eye on its operating temperature. Forward of that is a unique aspheric lens that features a rough spot to presumably scatter the light at the center of the beam.

Our vote for the most fascinating component has to go to the Neutral Density (ND) filter, which is used to control the intensity of the light. In a more pedestrian light source you could just dim the bulb, but in this case, the Wolf 5151 uses a metal disk with an array of holes drilled into it. By rotating the disc with a DC motor, the lens can be variably occluded to reduce the amount of light that reaches the aperture, which connects to the fiber cable.

While it’s perhaps no surprise the build quality of this medical gear is considerably beyond the commercial gadgets most of us get to play with, it still doesn’t hold a candle (no pun intended) to the laser module pulled from a Tornado jet fighter.

Knowing Your Place: The Implications Of GPS Spoofing And Jamming

May 23, 2022 by 26 Comments

Artificial satellites have transformed the world in many ways, not only in terms of relaying communication and for observing the planet in ways previously inconceivable, but also to enable incredibly accurate navigation. A so-called global navigation satellite system (GNSS), or satnav for short, uses the data provided by satellites to pin-point a position on the surface to within a few centimeters.

The US Global Positioning System (GPS) was the first GNSS, with satellites launched in 1978, albeit only available to civilians in a degraded accuracy mode. When full accuracy GPS was released to the public under the 1990s Clinton administration, it caused a surge in the uptake of satnav by the public, from fishing boats and merchant ships, to today’s navigation using nothing but a smartphone with its built-in GPS receiver.

Even so, there is a dark side to GNSS that expands beyond its military usage of guiding cruise missiles and kin to their target. This comes in the form of jamming and spoofing GNSS signals, which can hide illicit activities from monitoring systems and disrupt or disable an enemy’s systems during a war. Along with other forms of electronic warfare (EW), disrupting GNSS signals form a potent weapon that can render the most modern avionics and drone technology useless.

With this in mind, how significant is the threat from GNSS spoofing in particular, and what are the ways that this can be detected or counteracted?

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A fusion splicer being used to repair an optical fiber

Using A Fusion Splicer To Repair A Samsung TV’s Cable

May 23, 2022 by 28 Comments

Some Samsung TVs come with a system called One Connect, where all external cabling is connected to a separate box so that only one small signal cable goes to the TV. In some versions, the cable linking the TV with its Connect Box is a pure fiber optic cable that’s nearly transparent and therefore easy to hide.

Thin fiber optic cables are fragile however; when [Elecami Wolf] got one of these TVs for a very low price it turned out that this was because its One Connect cable had snapped. Replacement cables are quite expensive, so [Elecami Wolf] went on to investigate the inner workings of the fiber optic cable and figured out how to repair a broken one.

The cable consists of four pairs of plastic-coated glass fibers, which are attached to receivers and transmitters inside the thick connectors on either end. Repairing the cable required two things: figuring out which fibers should connect to each other, and a reliable way of connecting them together.

The first was difficult enough: a simple 1:1 connection didn’t work, so it took a bit of work to figure out the correct connection setup. One clever trick was pointing a camera at a working cable and comparing the flashing lights at each end; this helped to identify the right order for two of the four pairs. For the other two, a combination of reverse-engineering the electronic circuits and some systematic trial-and-error yielded a complete wiring diagram.

For the second part, [Elecami Wolf] called on a fiber optic expert who lent him a fusion splicer. This is a rather neat piece of equipment that semi-automatically brings two pieces of fiber together and welds them with an electric arc. Once this was complete, it was a matter of covering the splices to protect them from sharp bends, and the fancy TV was working again.

Although not everyone will have access to a multi-mode fusion splicer machine, [Elecami Wolf]’s videos provide fascinating insights into the workings of modern fiber-optic based consumer electronics. This might be the first fiber-optic splicing attempt we’ve seen; but if you’re trying to hook up an optical fiber to your circuit, this ball lens setup is a neat trick.

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Lotus 123 For Linux Is Like A Digital Treasure Hunt

May 23, 2022 by 49 Comments

Ever hear of Lotus 123? It is an old spreadsheet program that dominated the early PC market, taking the crown from incumbent Visicalc. [Tavis Ormandy] has managed to get the old software running natively under Linux — quite a feat for software that is around 40 years old and was meant for a different operating system. You can see the results in glorious green text on a black screen in the video below.

If you are a recent convert to Linux, you might not remember what a pain it was “in the old days” to install software. But in this case, it is even worse since the software isn’t even for Linux. The whole adventure started with [Tavis] wanting to find the API kit used to add plugins to Lotus. In theory, you could use it to add modern features to the venerable spreadsheet program.

The $395 software development kit wasn’t very common and there was also a Unix version of Lotus 123, but no one seemed to have a copy of that. [Tavis] eventually found someone who ran a circa-1990 BBS and had the data on tape. Turned out there was a hot copy of the SDK that he was able to use. But he noticed something else in the BBS’s list of files: the long-lost Unix version of Lotus!

An investigation found the installer used TD0 files which took some research. Luckily, a utility exists that can convert these to raw disk images. Inside was a very large object file. Apparently, in the days without dynamic loading, that object would be linked with plug in modules to install them.

The object file had all of its debugging information intact which shed a lot of light on the program’s internal operations. The old executables used COFF format but it is possible to relink it to an ELF file. Of course, it isn’t just that easy. [Tavis] wrote a small program to remove the old-style Unix system calls so they could be rerouted to Linux system calls. Some calls just pass through, but others need some translation due to differences in things like structure layout, sizes, and alignment.

In the end, it all worked but didn’t have a valid license. However, [Tavis] felt like since he did have a license and the software is abandoned, he was within his rights to crack the license check.

We are well-known abusers of spreadsheets around here. Of course, we aren’t the only ones.

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Do Flat Tyres Make Your Speedo Lie?

May 22, 2022 by 41 Comments

There are some engineering questions that may not have huge importance in the world, but which become the subject of intense idle speculation. A good example is the question of whether a lower tyre pressure on a motor vehicle would make a difference to the indicated speed. There are several contrasting intuitive theories as to what should happen, so [mechatronicsguy] has taken the time for a bit of experimentation in order to find out what really happens.

At stake were the change in effective radius from a flattened portion of the tyre, the so-called tank tracks effect in which the entire circumference of the tyre is still traversed, and the prospect of a change in circumference due to the different pressure. The test wheels were made from foam, and were found to give a different reading when compressed. This might solve toe problem, but of course real car wheels have radial wires to give them stiffness. When these were simulated on the foam wheels with packing tape, the difference evaporated. Later this was confirmed by GPS-measuring a real car with deflated wheels.

All this makes for a fascinating read, because after all, there’s sometimes no substitute for a real-world test.

Header image: Gerlach, Public domain.

Truly Giant Telescope Could Image Exoplanets

May 22, 2022 by 19 Comments

Have you ever wished we could peek at all these exoplanets that have been recently discovered? We aren’t likely to visit anytime soon, but it would be possible to build a truly giant telescope that could take a look at something like that. At least according to [SciShow Space] in a recent video you can see below.

The idea put forth in a recent scientific paper is to deliberately create the conditions that naturally form gravitational lenses. If you recall, scientists have used these naturally-occurring lenses to image the oldest star ever observed. These natural super-telescopes have paid off many times, but you can’t pick what you want to look at. It is all a function of the distance to the star creating the lens and the direction a line between us points.

But what if you could create your own gravity lens? Granted, we probably aren’t going to do that in our garages. However, a recent paper talks about launching an optical detector that you could maneuver so that it was on a line that would pass through the object you want to see and our own sun. We clearly have the technology to do this. After all, we have several nice space telescopes, and several probes operating far away from the sun.

That is one of the biggest catches, though. This new telescope will need to be some 550 AU from the sun to get good results. For the record, the Earth is 1 AU (about 8 light minutes) out. Pluto — maybe not a planet anymore, but still a signpost on the way out of the solar system — is a scant 39 AU out. Voyager I, which has been racing away from the sun since 1977 is only about 156 AU out.

Because the craft would be so far out, it would be practically a one-shot mission. You also have to have something reliable enough to go the 17 years it would take with today’s technology to get in place. You also need a way to get the data back over that distance. All doable, but non-trivial.

The paper simulates what the Earth would look like using this technique from a nearby star. The images are shockingly good, especially after a bit of post-processing. Meanwhile, we may have to settle for more modest images. You might not see detail, but it is possible to find exoplanets with reasonably modest equipment.

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