Keeping Track Of The Night Sky With Discrete Logic Chips

February 9, 2024 by 11 Comments

As hobbies go, stargazing has a pretty low barrier to entry. All you really need is a pair of Mark 1 eyeballs and maybe a little caffeine to help you stay up late enough. Astronomy, on the other hand, takes quite a bit more equipment, not least of which is a telescope and a way to get it pointed in the right direction at the right time, and to make up for the pesky fact that we’re on a moving, spinning ball of rock.

Yes, most of the equipment needed for real astronomy is commercially available, but [Mitsuru Yamada] decided to go his own way with this homebrew retro-style telescope motor controller. Dubbed MCT-6, the controller teams up with his dual-6502 PERSEUS-9 computer to keep his scope on target. There are a lot of literally moving parts to this build, including the equatorial mount which is made from machined aluminum and powered by a pair of off-the-shelf stepper-powered rotary stages for declination and right ascension. The controller that runs the motors is built completely from discrete 74HCxx logic chips that divide down a 7.0097-MHz crystal oscillator signal to drive the steppers precisely at one revolution per diurnal day. The pulse stream can also be sped up for rapid slewing, to aim the telescope at new targets using a hand controller.

As impressive as all this is, the real star (sorry) of the show here is the fit and finish. In typical [Yamada-san] fashion, the impeccably wire-wrapped mainboard fits in a robust die-cast aluminum case that fits the retro aesthetic of the whole project. The PERSEUS-9 is used mainly as a display and control terminal, running custom software to show where the telescope is pointed and calculate the coordinates of various heavenly bodies. As a bonus, the 40×7 alphanumeric red LED display should be easy on dark-adapted eyes.

Hats off to [Mitsuru Yamada] on another fabulous build. If you haven’t had enough of his build style yet, be sure to check out his PERSEUS-8 or even his foray into the analog world.

Continue reading “Keeping Track Of The Night Sky With Discrete Logic Chips” →

A Tube Tester Laid Bare

February 8, 2024 by 13 Comments

There’s still a mystique around vacuum tubes long after they were rendered obsolete by solid state devices, and many continue to experiment with them. They can be bought new, but most of us still come to them through the countless old tubes that still litter our junk boxes. But how to know whether your find is any good? [Rob’s Fixit Shop] took a look at a tube tester, once a fairly ubiquitous item, but now a rare sight.

To look at it’s a box with an array of tube sockets, a meter, and a set of switches to set the pinout for the tube under test. We expected it to use a common-cathode circuit, but instead it measures leakage between the grid and the other electrodes, a measure of how good the vacuum in the device is. In a worrying turn this instrument can deliver an electric shock, something he traces to a faulty indicator light leading to the chassis. We are however still inclined to see it as anything but safe, because the lack of mains isolation still exposes the grid to unwary fingers.

All in all though it’s an interesting introduction to an unusual instrument, and given a suitable isolating transformer we wouldn’t mind the chance to have one ourselves. If you need to test a tube and don’t have one of these, don’t worry. It’s possible to roll your own.

Continue reading “A Tube Tester Laid Bare” →

Friendly Flexible Circuits: The Cables

February 7, 2024 by 18 Comments

Flexible cables and flex PCBs are wonderful. You could choose to carefully make a cable bundle out of ten wires and try to squish them to have a thin footprint – or you could put an FFC connector onto your board and save yourself a world of trouble. If you want to have a lot of components within a cramped non-flat area, you could carefully design a multitude of stuff FR4 boards and connect them together – or you could make an FPC.

Flexible cables in particular can be pretty wonderful for all sorts of moving parts. They transfer power and data to the scanner head in your flat-bed scanner, for instance.  But they’re in fixed parts too.  If you have a laptop or a widescreen TV, chances are, there’s an flexible cable connecting the motherboard with one or multiple daughterboards – or even a custom-made flexible PCB. Remember all the cool keypad and phones we used to have, the ones that would have the keyboard fold out or slide out, or even folding Nokia phones that had two screens and did cool things with those? All thanks to flexible circuits! Let’s learn a little more about what we’re working with here.

FFC and FPC, how are these two different? FFC (Flexible Flat Cable) is a pre-made cable. You’ve typically seen them as white plastic cables with blue pieces on both ends, they’re found in a large number of devices that you could disassemble, and many things use them, like the Raspberry Pi Camera. They are pretty simple to produce – all in all, they’re just flat straight conductors packaged nicely into a very thin cable, and that’s why you can buy them pre-made in tons of different pin pitches and sizes. If you need one board to interface with another board, putting an FFC connector on your board is a pretty good idea.

Continue reading “Friendly Flexible Circuits: The Cables” →

Biomedical Engineering Hack Chat

February 5, 2024 by No comments

Join us on Wednesday, February 7 at noon Pacific for the Biomedical Engineering Hack Chat with Nyeli Kratz!

Although medical doctors and engineers generally work in completely different domains, there’s a fair amount of overlap between the disciplines. At the end of the day, they both solve problems, and while doctors clearly focus on the biological aspects of disease, there just might come a point where the problem has to be addressed with engineering principles. From the intricate design of an artificial hip to the electrical interface between an amputee’s nervous system and a prosthetic limb, biomedical engineers can make a tremendous contribution to positive patient outcomes.

join-hack-chatNyeli Kratz, a recent biomedical engineering grad, has worked on quite a few engineering solutions to diseases. Many of her projects, like this stand-up mobility aid or a wheelchair attachment that lets a tetraplegic father interact with his newborn child, seem aimed at making it easier for patients to interact with the world. She’ll stop by the Hack Chat to talk about these projects in particular as well as what the engineer brings to the table when it’s time to design hardware that heals.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, February 7 at 12:00 PM Pacific time. If time zones have you tied up, we have a handy time zone converter.

Arctic Adventures With A Data General Nova II — The Equipment

February 5, 2024 by 50 Comments

As I walked into the huge high bay that was to be my part-time office for the next couple of years, I was greeted by all manner of abandoned equipment haphazardly scattered around the room. As I later learned, this place was a graveyard for old research projects, cast aside to be later gutted for parts or forgotten entirely. This was my first day on the job as a co-op student at the Georgia Tech Engineering Experiment Station (EES, since renamed to GTRI). The engineer who gave me the orientation tour that day pointed to a dusty electronic rack in one corner of the room. Steve said my job would be to bring that old minicomputer back to life. Once running, I would operate it as directed by the radar researchers and scientists in our group. Thus began a journey that resulted in an Arctic adventure two years later.

The Equipment

The computer in question was a Data General (DG) mini computer. DG was founded by former Digital Equipment Corporation (DEC) employees in the 1960s. They introduced the 16-bit Nova computer in 1969 to compete with DEC’s PDP-8. I was gawking at a fully-equipped Nova 2 system which had been introduced in 1975. This machine and its accessories occupied two full racks, with an adjacent printer and a table with a terminal and pen plotter. There was little to no documentation. Just to turn it on, I had to pester engineers until I found one who could teach me the necessary front-panel switch incantation to boot it up. Continue reading “Arctic Adventures With A Data General Nova II — The Equipment” →

Avocado-Shaped Robot Makes Its Way Through The Rainforest

February 3, 2024 by 12 Comments

When you think of a robot getting around, you probably think of something on wheels or tracks. Maybe you think about a bipedal walking robot, more common in science fiction than our daily lives. In any case, researchers went way outside the norm when they built an avocado-shaped robot for exploring the rainforest.

The robot is the work of doctoral students at ETH Zurich, working with the Swiss Federal Institute for Forest, Snow, and Landscape research. The design is optimized for navigating the canopy of the rainforest, where a lot of the action is. Traditional methods of locomotion are largely useless up high in the trees, so another method was needed.

The avocado robot is instead tethered to a cable which is affixed to a high branch on a tree, or even potentially a drone flying above. The robot then uses a winch to move up and down as needed.  A pair of ducted fans built into the body provide the thrust necessary to rotate and pivot around branches or other obstacles as it descends. It also packs a camera onboard to help it navigate the environment autonomously.

It’s an oddball design, but it’s easy to see how this design makes sense for navigating the difficult environment of a dense forest canopy. Sometimes, intractable problems require creative solutions. Continue reading “Avocado-Shaped Robot Makes Its Way Through The Rainforest” →

Navigate Burning Man With Ease With This Custom Tool

February 1, 2024 by 7 Comments

When setting up a city in the desert, the team behind Burning Man does its best to lay things out in an ordered fashion. Even still, getting around at ground level can be a challenge at times, and it’s easy to get lost. To help get around easier, [Zach] developed a nifty GPS device built specifically for navigating the ephemeral clock-like city.

The device is built for a few simple purposes. It shows where you are, it helps you navigate somewhere you’ve been before, and it helps you navigate to portable toilets. It’s set up to be usable both on bike and on foot, the typical ways of getting around the playa. Since Black Rock City is fairly simple, it uses an arrow to point to a desired waypoint, and is capable of storing up to five points of interest. It’s built using a cheap GNSS receiver and transflective LCD screen, and a Pi Pico is the brains of the operation.

The value of the device is obvious, particularly when exploring deeper areas of the playa, or after the road signs have been removed or structures have been taken down or burnt to ashes. We’ve seen some other great projects from the desert festival before, too. If you’ve got your own playa-spec hacks, don’t hesitate to let us know!