Smallest Discrete Transistor 555 Timer

May 11, 2021 by Chris Lott 28 Comments

Over at Tiny Transistor labs, [Robo] took it upon himself to reproduce the classic 555 timer in discrete transistor form. For bonus points, he also managed to put it in a package that’s the same basic size, pin compatible with, and a plug-in replacement for the original. The first task was deciding which 555 circuit to implement. He examined a handful of different implementations — and by examined, we mean dissected them and studied the die circuitry under a microscope. In the end, he went with Hans Camenzind’s original circuit, both as a tribute and because it used the fewest transistors — a point which helped manage the final size, which is only a little bit bigger than the IC!

Speaking of sizes, have you ever soldered an EIA 01005 resistor? We agree with [mbedded.ninja] who wrote on a post about standard chip resistor sizes, the 01005 is a “ridiculously small chip package that can barely be seen by the naked eye.” It is 16 thou x 8 thou (0.4 mm x 0.2 mm) in size, and despite its name and placement in the Imperial series, it is not half the size of an 0201. The transistors are your standard 2N3904 / 2N3906, but purchased in a not-so-standard DFN (Dual Flat Pack, No Leads). We might think a 1.0 x 0.6 mm component as small, but compared to its neighboring resistors in this circuit, it’s huge.

[Robo] has done this kind of project before, most recently making a discrete recreation of of the classic 741 op-amp. We covered a similar, but larger, discrete 555 timer project back in 2011. If you want to go really big-scale with your own reproduction project, check out the MOnSter 6502 from five years ago for further inspiration. Thanks to [Lucas] for the tip.

A Soyuz Space Clock Replica

March 8, 2021 by Chris Lott 16 Comments

If you like the retro look of old Soviet space hardware, then this replica of the model 774H Soyuz digital clock by [David Whitty] might be the perfect accessory for your desk. Forgoing the original stack of ten jam-packed circuit boards, [David] used an Arduino, a GPS receiver, and a handful of other common parts to create a convincing reproduction.

He also made some functional changes to make it better suited as an ordinary clock for us earthbound folk. If you want to take on this project yourself, be prepared for some real metalwork. No 3D printing filament was harmed in building this project. It’s based on a pair of heavily modified Hammond cast aluminum enclosures, with over 1 kg of lead ballast added to give it the appropriate heft of the original. The GPS patch antenna is cleverly hidden on the rear interface connector, but a discrete hole for a USB connector gives away the secret that this isn’t an original. The software (free for non-commercial use) and build notes are available on his GitHub repository.

We covered [Ken Shirriff]’s fascinating dive into the guts of a real Soyuz digital clock back in January. If old space hardware is your thing, you should definitely check out this teardown by [CuriousMarc] of the 653B, the 1960s-era electro-mechanical predecessor to the 774H. Thanks to [CuriousMarc] for bringing this project to our attention.

Continue reading “A Soyuz Space Clock Replica” →

Reproduction 1960s Computer Trainer Really Pushes Our Buttons

June 28, 2020 by Dan Maloney 13 Comments

If you were selling computers in the early 1960s you faced a few problems, chief among them was convincing people to buy the fantastically expensive machines. But you also needed to develop an engineering force to build and maintain said machines. And in a world where most of the electrical engineers had cut their teeth on analog circuits built with vacuum tubes, that was no easy feat.

To ease the transition and develop some talent, Digital Equipment Corporation went all out with devices like the DEC H-500 Computer Lab, which retrocomputing wizard [Michael Gardi] is currently building a reproduction of. DEC’s idea was to provide a selection of logic gates, flip flops, and other elements of digital electronics that could be hooked together into more complicated circuits. We can practically see the young engineers in their white short-sleeve shirts and skinny ties laboring over the H-500 in a lab somewhere.

[Mike] is fortunate enough to ~~have~~ have access to an original H-500, but he wants anyone to be able to build one. His project page and the Instructables post go into great detail on how he made everything from the front panel to the banana plug jacks; almost everything in the build aside from the wood frame is custom 3D printed to mimic the original as much as possible. But the pièce de résistance is those delicious, butterscotch-colored DEC rocker switches. Taking some cues from custom switches he had previously built, he used reed switches and magnets to outfit the 3D printed rockers and make them look and feel like the originals. We can’t wait for the full PDP build.

Hats off to [Mike] for another stunning reproduction from the early years of the computer age. Be sure to check out his MiniVac 601 trainer, the Digi-Comp 1 mechanical computer, and the paperclip computer. If you’d like to pick [Mike’s] brain about this or any of his other incredible projects, he’ll be joining us for a Hack Chat in August.

Thanks to [Granzeier] for the tip!

What Does Your Necklace Say?

February 17, 2020 by Brian McEvoy 2 Comments

If we write about sound reproduction, there is a good chance we found a home-made amplifier or an upcycled speaker system. In this case, you don’t use your ears to appreciate the sound; you use your hands or eyes. [ElatisEagles] converted an amplitude sound graph into a wearable bead. Even without much background it should be immediately recognizable for what it is. Presumably, they converted a sound wave to vectors, then used the “Revolve” function in Rhino, their software of choice. Sometimes this is called a “lathe” function. Resin printers should be able to build these without supports and with incredible fidelity.

Some tattoos put a sound wave on the skin, and use an app to play it back, but if you want to wear a sound bite from your favorite show and not get branded as the “Pickle Rick” gal/guy at the office, maybe swap out the color and sound wave before it goes stale. We would wear a bead that says, “drop a link in our tip line,” but you can probably think of something more clever.

We have other high-tech ornamentation that leverages motion instead of sound, or how about a necklace that listens instead.

Continue reading “What Does Your Necklace Say?” →

Antique Lighthouse Lens Via CNC

May 11, 2018 by Bryan Cockfield 22 Comments

Before the invention of the high-powered LED, and even really before the widespread adoption of electric lights in general, lighthouses still had the obligation of warning ships of dangers while guiding them into various safe harbors. They did this with gas lights and impressive glass lenses known as Fresnel lenses which helped point all available light in the correct direction while reducing weight and material that would otherwise be used in a conventional lens.

Now, a company in Florida is using acrylic in reproductions of antique Fresnel lenses. At first glance, it seems like acrylic might not be the best substitute for glass, but the company is able to achieve extreme precision using a CNC machine and then polishing and baking the acrylic which makes it transparent and excellent for use in lighthouse lenses like this. The reproduction lenses are built out of brass, and the lens elements are glued in place with a special adhesive. It’s a convincing replication worthy of use in any lighthouse.

Be sure to check out the video below to see how these lenses are built, and although we’re not entirely sure what exactly is being sprayed on the lenses when they are being polished, perhaps someone in the comments section can illuminate that for us. Of course, there are other uses for Fresnel lenses than in lighthouses, and we’ve seen some great examples of them put to use for many different applications.

Continue reading “Antique Lighthouse Lens Via CNC” →

Bantam-sized Jukebox Reproduction Tops The Fabrication Charts

February 4, 2017 by Dan Maloney 2 Comments

Restoring a genuine vintage jukebox is a fun project, but finding suitable candidates can be a difficult proposition. Not only can a full-size machine take a huge bite out of your wallet, it can take up a lot of room, too. So a replica miniature jukebox might be just the thing.

We have to admit, at first glance [Allan_D_Murray]’s project seemed like just another juke upgrade. It was only after diving into his very detailed build log that we realized this classic-looking juke is only about 30″ (80 cm) tall. It’s not exactly diminutive, but certainly more compact than the original Wurlitzer 1015 from which it draws its inspiration. But it sure looks like the real thing. Everything is custom made, from the round-top case to the 3D-printed trim pieces, which are painted to look like chrome-plated castings. The guts of the juke are pretty much what you’d expect these days — a PC playing MP3s. But an LCD monitor occupies the place where vinyl records would have lived in the original and displays playlists of the albums available. There’s an original-looking control panel on the front, and there are even bubblers in the lighted pilasters and arches.

Hats off to [Allan] for such a detailed and authentic tribute to a mid-century classic. But if a reproduction just won’t cut it for you, check out this full-size juke with the original electronics.

Continue reading “Bantam-sized Jukebox Reproduction Tops The Fabrication Charts” →

Reproducing A DSKY

February 3, 2015 by Brian Benchoff 32 Comments

This is a project that is about a year and a half in the making, but [Fran] is finally digging into the most iconic part of the Apollo Guidance Computer and building the most accurate reproduction DSKY ever.

The Apollo Guidance Computer was a masterpiece of engineering and is frequently cited as the beginning of the computer revolution, but it didn’t really look that interesting – it looks like a vastly overbuilt server blade, really. When everyone thinks about the Apollo Guidance Computer, they think about the DSKY, the glowey keypad interface seen in the blockbuster hit Apollo 13 and the oddly accurate disappointment of Apollo 18. It’s the part of the Apollo Guidance Computer the Apollo astronauts actually interacted with, and has become the icon of the strange, early digital computers developed for NASA in the 60s.

There are a few modern DSKY replicas, but all of them are exceedingly anachronistic; all of these reproductions use seven-segment LEDs, something that didn’t exist in the 1960s. A true reproduction DSKY would use custom electroluminescent displays. These EL segments are powered by AC, and transistors back then were terrible, leading to another design choice – those EL segments were turned on and off by relays. It’s all completely crazy, and aerospace equipment to boot.

Because of the custom design and engineering choices that seem insane to the modern eye, there isn’t much in the way of documentation when it comes to making a reproduction DSKY. This is where [Fran] tapped a few of the contacts her historical deconstruction cred earned when she reverse engineered a Saturn V Launch Vehicle Digital Computer to call upon anyone who would have access to a real Apollo-era DSKY.

The first contact was the Kansas Cosmosphere who was kind enough to send extremely detailed photographs of the DSKYs in their archives. It would have been extremely nice to have old documentation made when the DSKYs were rolling off the assembly line, but that information is locked away in a file cabinet owned by Raytheon.

[Fran] got a break when she was contacted by curators at the National Air and Space Museum’s Garber facility who invited her down to DC. She was given the grand tour, including the most elusive aircraft in the museum’s collection, the Ho 229, the dual-turbojet Nazi flying wing. At the Garber facility, [Fran] received permission to take apart two DSKYs.

The main focus of [Fran]’s expedition to the Air and Space Museum was to figure out how the EL displays were constructed. The EL displays that exist today are completely transparent when turned off because of the development of transparent conductors.

The EL displays in the DSKY were based on earlier night lights manufactured by Sylvania. After looking at a few interesting items that included Gemini hardware and early DSKYs, this sort of construction was confirmed.

With a lot of pictures, a lot of measurements, a lot of CAD work, and some extremely tedious work, [Fran] was able to create the definitive reference for DSKY display elements. There are 154 separate switchable element in the display, all controlled by relays. These elements are not multiplexed; every element can be turned on and off individually.

Figuring out how the elements were put together was only one part of [Fran]’s research. Another goal was to figure out the electrical connections between the display and the rest of the DSKY. There, [Fran] found 160 gold pins in a custom socket. It’s bizarre, and more like a PGA socket than like the backplane connector [Fran] found in the Saturn V computer.

Even though [Fran]’s research was mostly on the EL panel inside the display, she did get a few more insights with her time with the DSKYs. The buttons are fantastic, and the best keys she’d ever used. This is just part one of what will be an incredibly involved project, and we’re looking forward to what [Fran] looks into next.