A Look Inside A Vintage Aircraft Altimeter

May 10, 2023 by Dan Maloney 21 Comments

There’s a strange synchronicity in the projects we see here at Hackaday, where different people come up with strikingly similar stuff at nearly the same time. We’re not sure why this is, but it’s easily observable, with this vintage altimeter teardown and repair by our good friend [CuriousMarc] as the latest example.

The altimeter that [Marc] dissects in the video below was made by Kollsman, which is what prompted us to recall this recent project that turned a jet engine tachometer into a CPU utilization gauge. That instrument was also manufactured by Kollsman, but was electrically driven. [Marc]’s project required an all-mechanical altimeter, so he ordered a couple from eBay.

Unfortunately, thanks to rough handling in transit they arrived in less than working condition, necessitating the look inside. For which we’re thankful, of course, because the guts of these aneroid altimeters are quite impressive. The mechanism is all mechanical, with parts that look like something [Click Spring] would make for a fine timepiece. [Marc]’s inspection revealed the problem: a broken pivot screw keeping the expansion and contraction of the aneroid diaphragms from transmitting force to the gear train that moves the needles. The repair was a little improvisational, with 0.5-mm steel balls used to stand in for the borked piece. It may not be flight ready, but it worked well enough to get the instrument back in action.

We suspect that [Marc] won’t be able to leave well enough alone on this one, so we’ll be on the lookout for a proper repair. In the meantime, he’ll be able to use this altimeter in the test setup he’s building to test a Bendix air data computer from a 1950s-era jet fighter. Continue reading “A Look Inside A Vintage Aircraft Altimeter” →

PC Classics, Right In Your Browser With EmuOS

May 6, 2023 by Donald Papp 11 Comments

[Emupedia]’s work to preserve computer history by way of making classic and abandoned games and software as accessible as possible is being done in a handy way: right in your browser with EmuOS.

A few moments of BIOS startup kicks off EmuOS right in a browser window.

Doing things this way has powerful “Just Works” energy. Visit that link in a modern browser and in no time at all you’ll be looking at a Windows 95 (or Windows 98, or Windows ME) desktop, filled with a ton of shortcuts to pre-installed and ready-to-run classic software. Heck, you can even keep it simple and be playing the original Microsoft Solitaire in no time flat. There is also a whole ton of DOS software waiting to be fired up, just double-click the DOSBox icon, and browse a huge list. The project is still in development, so not everything works, but the stuff that does is awfully slick.

Here’s some additional background that goes into more detail about the project and its capabilities, but if you’d prefer to just click around to explore, here’s the main link again (and here’s a list of mirrors.)

If OS emulation is your thing, don’t miss emulating the IBM PC on an ESP32 microcontroller. And if you’re more into lesser-known vintage operating systems, how about re-inventing PalmOS to run on x86 architecture?

Hackaday Links: April 30, 2023

April 30, 2023 by Dan Maloney 17 Comments

Cloudy with a chance of concrete? The “success” of last week’s brief but eventful Starship launch has apparently raised some regulatory eyebrows, with the Federal Aviation Administration launching an investigation into the destruction wrought by the mighty rocket. And it’s not just the hapless Dodge Caravan that they’re concerned with — although we found some fantastic POV footage that shows the kill shot as well as close-ups of the results — but also the damage rained down upon residents around the Boca Chica launch complex. Tons of concrete and rebar were excavated by the 33 Raptor engines during the launch and sent in all directions, reportedly landing up to 6 miles (10 kilometers) from the pad. What’s worse, a lot of debris ended up on beaches that are home to endangered species, which has the Sierra Club also taking an interest. The FAA has apparently nixed any launches from the Texas facility until they complete their investigation.

Continue reading “Hackaday Links: April 30, 2023” →

Modded See ‘N Say Teaches The Sounds Of City Life

March 13, 2023 by Tom Nardi 19 Comments

The Fisher-Price See ‘n Say was introduced back in 1964, and since then has helped teach countless children the different sounds made by farm animals. But what about our urban youth? If they’re going to navigate a concrete jungle, why not prepare them to identify the sound of a jackhammer or the chime that plays before an announcement goes out over the subway’s PA system?

That’s the idea behind this hacked See ‘n Say [John Park] put together for Adafruit. Now we should note up front that no vintage toys were sacrificed during the production of this gadget — it seems Fisher-Price (predictably) dropped the tiny record player these toys used to use for a cheap electronic board sometime in the 90s. A quick check with everyone’s favorite A-to-Z megacorp shows you can pick up one of these new-school models for around $25 USD.

The modern electronic version of the toy is easy to mod.

Cracking open the electronic version of the See ‘n Say reveals a circular PCB with a series of membrane buttons that are pressed by the mechanics of the spinning pointer. As it so happens, there are handy test points next to each of these buttons, which makes it simple to wire up to a microcontroller.

In this case, it’s Adafruit’s KB2040, which is connected to a MAX98357A amplifier board over I2S. A small boost converter module is used to wring 5 volts out of the toy’s pair of AA batteries. The original speaker is repurposed, though [John] adds a physical power switch to keep the boost converter from flattening the alkaline batteries when not in use.

On the software side, all you’ve got to do is load the MCU with your sounds and write a bit of code that associates them with the button being pressed on the PCB. [John] gets his city sounds from Freesound, a community-maintained database of Creative Commons Licensed sounds, and provides the CircuitPython code necessary to tie everything together.

The last step is the artwork. For this project, [Brian Kesinger] provided some swanky vintage-looking imagery that perfectly fits the See ‘n Say style. The art is available under the NonCommercial-ShareAlike Creative Commons license, so you’re free to use it in your own version. Though naturally, that assumes you’ve decided to use the same sounds as [John] — the beauty of this project is that you could easily load it up with whatever sounds you’d like Hacker Junior to learn. Possibly a well-known Australian YouTuber?

If anyone feels inclined to build a Hackaday-themed See ‘n Say based on this project, we’ve love to see it.

Continue reading “Modded See ‘N Say Teaches The Sounds Of City Life” →

Retro Gadgets: Make Your Scope Dual Channel

February 21, 2023 by Al Williams 32 Comments

We live in a time when having an oscilloscope is only a minor luxury. But for many decades, a good scope was a major expense, and almost no hobbyist had a brand new one unless it was of very poor quality. Scopes were big and heavy and, at the price most people were willing to pay, only had a single channel. Granted, having one channel is better than having nothing. But if the relative benefit of having a single channel scope is 10 points, the benefit of having two channels is easily at least 100 points. So what was a poor hacker to do when a dual-trace or higher scope cost too much? Why, hack, of course. There were many designs that would convert a single trace scope into a poor-quality multichannel scope. Heathkit made several of these over the years like the ID-22, the ID-101, and the ID-4101. They called them “electronic switches.” The S-2 and S-3 were even earlier models, but the idea wasn’t unique to Heathkit and had been around for some time.

For $25, you could change your scope to dual trace!

There were two common approaches. With alternative or alt mode, you could trigger a sync pulse and draw one trace. Then trigger again and draw the second trace with a fixed voltage offset. If you do this fast enough, it looks like there are two traces on the screen at one time. The other way is to rapidly switch between voltages during the sweep and use the scope’s Z input to blank the trace when it is between signals. This requires a Z input, of course, and a fast switching clock. This is sometimes called “chopper mode” or, simply, chop. This wasn’t just the realm of adapters, though. Even “real” analog scopes that did dual channels used the same methods, although generally with the benefit of being integrated with the scope’s electronics.

Continue reading “Retro Gadgets: Make Your Scope Dual Channel” →

RCA’s Clear Plastic TV Wowed Crowds In 1939

February 12, 2023 by Donald Papp 25 Comments

In the United States in 1939, television sets still had a long way to go before they pretty much sold themselves. Efforts to do just that are what led to RCA’s Lucite Phantom Telereceiver, which aimed to show people a new way to receive broadcast media.

Created for the 1939 World’s Fair, the TRK-12 Lucite Phantom Telereceiver introduced people to the concept of television. Production models were housed in contemporary wood cabinets, but the clear acrylic (itself also a relatively new thing) units allowed curious potential customers to gaze within, and see what was inside these devices.

One interesting feature is the vertically-mounted cathode ray tube, which reflects off a mirror in the top cover of the cabinet for viewing. This meant that much of the bulk of the TRK-12 could be vertical instead of horizontal. Important, because the TRK-12 was just over a meter tall and weighed 91 kilograms (or just over 200 lbs.)

Clearly a luxury item, the TRK-12 sold for $600 which was an eye-watering sum for the time. But it was a glimpse of the future, and as usual, the future is made available a few ticks early to those who can afford the cost.

Want to see one in person? You might be in luck, because an original resides at the MZTV Museum of Television in Toronto, Canada.

One-Size-Fits-All Wrench Points To A Nut Job

January 17, 2023 by Anool Mahidharia 37 Comments

When [Hand Tool Rescue] came across a 1919 patent for a one size fits all wrench, he couldn’t help but recreate it. Described in the patent as “a new, original, ornamental design for a wrench”, the wrench had a slot for possibly every fastener that the inventor could think of. Not only did it have slots for several hexagonal fasteners, but many others for octagonal, square and even a pentagonal fastener.

[Hand Tool Rescue] reckons there are 47 slots for various sizes and types of fasteners, not counting the ones whose purpose he could not fathom. Just in case he missed any fastener sizes, the original designer decided to add an alligator wrench at the other end of the handle, potentially negating the need for any of the other slots. The tool even features a sharp edge along one of the sides, possibly for use as a scraper of some kind.

Why such a crazy design was patented, or what were the functions of some of its slots are questions that will likely remain unanswered. At best, we can all take guesses at solving the mystery of this tool. [Hand Tool Rescue] scales the original drawing such that one of the slots has a width of 1 inch, and then uses that as a template to recreate the wrench. He starts with a slab of 3/8th inch thick, grade 4140 steel, which has a high strength to weight ratio and can be case hardened after machining, making it suitable for this ornamental project.

He then embarks on his journey of excessive milling, drilling, filing, band sawing and shaping (using a slotting attachment), totaling about 11 hours worth of drudgery. Of course, one could argue that it would have been much easier, and accurate, to have used modern machining methods. And we are spoilt for choices here among laser cutting, water jet cutting or even EDM machining, any of which would have done the job faster, cleaner and more precisely. But we guess [Hand Tool Rescue] wanted to stick to traditional methods as would have been available in 1919 to an inventor who wanted to make a prototype of his awesome, all in one wrench.

If you can help explain the overall function of this wrench, or identify some of the more vague slots in it, then [Hand Tool Rescue] would be happy to get the feedback. And talking about less desirable wrenches, check out how this Sliding Wrench Leaves a Little to be Desired.

Continue reading “One-Size-Fits-All Wrench Points To A Nut Job” →