Author: Dan Maloney

3372 Articles

Old Dot-Matrix Displays Give Up Their Serial Secrets

June 4, 2024 by 11 Comments

If there’s one thing we like better around here than old, obscure displays, it’s old, obscure displays with no documentation that need a healthy dose of reverse engineering before they can be put to use. These Plessey dot-matrix displays are a perfect example of that.

We’re not sure where [Michael] scored these displays, but they look fantastic. Each 8-pin DIP has two 5×7-matrix, high-visibility LED displays. They bear date codes from the late 80s under the part number, GPD340, but sadly, precious little data about them could be dredged up from the Interwebz. With 70 pixels and only six pins after accounting for power and ground, [Michael] figured there would be a serial protocol involved, but which pins?

He decided to brute-force the process of locating them, using a Pico to sequentially drive every combination while monitoring the current used with a current sensor. This paid off after only a few minutes, revealing that each character of the display has its own clock and data pins. The protocol is simple: pull the clock and data pins high then send 35 bits, which the display sorts out and lights the corresponding pixels. The video below shows a 12-character scrolling display in action.

Plessey made a lot of displays for military hardware, and these chunky little modules certainly have a martial air about them. Given that and the date code, these might have come from a Cold War-era bit of military hardware, like this Howitzer data display which sports another Plessey-made display.

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Hackaday Links: June 2, 2024

June 2, 2024 by 6 Comments

So you say you missed the Great Solar Storm of 2024 along with its attendant aurora? We feel you on that; the light pollution here was too much for decent viewing, and it had been too long a day to make a drive into the deep dark of the countryside survivable. But fear not — the sunspot that raised all the ruckus back at the beginning of May has survived the trip across the far side of the sun and will reappear in early June, mostly intact and ready for business. At least sunspot AR3664 seems like it’s still a force to be reckoned with, having cooked off an X-class flare last Tuesday just as it was coming around from the other side of the Sun. Whether 3664 will be able to stir up another G5 geomagnetic storm remains to be seen, but since it fired off an X-12 flare while it was around the backside, you never know. Your best bet to stay informed in these trying times is the indispensable Dr. Tamitha Skov.

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Inside A Mystery Aerospace Computer With [Ken Shirriff]

June 1, 2024 by 10 Comments

When life hands you a mysterious bit of vintage avionics, your best bet to identifying it might just be to get it in front of the biggest bunch of hardware hounds on the planet. After doing a teardown and some of your own investigation first, of course.

The literal black box in question came into [Ken Shirriff]’s custody courtesy of [David] from Usagi Electric, better known for his vacuum tube computer builds and his loving restoration of a Centurion minicomputer. The unit bears little in the way of identifying markings, but [Ken] was able to glean a little by inspecting the exterior. The keypad is a big giveaway; its chunky buttons seem optimized for use with the gloved hands of a pressure suit, and the ordinal compass points hint at a navigational function. The layout of the keypad is similar to the Apollo DSKY, which might make it a NASA artifact. Possibly contradicting all of that is the oddball but very cool electromechanical display, which uses reels of digits and a stepper-like motor to drive them.

Inside, more mysteries — and more clues — await. Unlike a recent flight computer [Ken] looked at, most of the guts are strictly electronic. The instrument is absolutely stuffed with PCBs, most of which are four-layer boards. Date codes on the hundreds of chips all seem to be in the 1967 range, dating the unit to the late 60s or early 70s. The weirdest bit is the core memory buried deep inside the stacks of logic and analog boards. [Ken] found 20 planes with the core, hinting at a 20-bit processor.

In the end, [Ken] was unable to come to any firm conclusion as to what this thing is, who made it, or what its purpose was. We doubt that his analysis will end there, though, and we look forward to the reverse engineering effort on this piece of retro magic.

A Look Inside The Geochron Clock

May 31, 2024 by 6 Comments

There are plenty of cool clocks out there, and maps by their very essence are cool, too. But a map that’s also a clock — or is it a clock that’s also a map? — has to be the coolest thing ever.

Of course we’re talking about the Geochron, a world clock that makes the relationship between the Earth and the Sun clear and has graced the offices of executives who want to impress visitors with the global nature of their importance for decades. [Attoparsec] has long coveted one of these electromechanical beauties, and when a used one popped up online for a pittance, at least compared to what they cost new, he jumped at the chance.

The Geochron he ended up with was in need of some TLC, but surprisingly little considering its mid-1980s vintage. The real treat in the video below is getting to see how these wonderful devices work. They’re basically simple slide projectors. While we here in the future would simply do everything in software on a nice flat-screen display, the base map, night-day terminators, and calendar are all contained on transparent elements that move under the power of a synchronous motor across a lighted platen. The analemma display is particularly cool; an indicator tracks the Sun’s position over the Earth with a cam that encodes the equation of time in its shape, moving through its familiar bi-lobed loop as the seasons progress.

Any clock that comes with a set of blueprints for installation purposes is alright in our book, and kudos to [Attoparsec] for landing this prize and getting it back in shape. His description of it as “the greatest clock of all time” is apt, but perhaps with a little competition. Or maybe a lot.

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Tiny Orrery Is A Watchmaker’s Tour De Force

May 30, 2024 by 3 Comments

Six tiny gears, a few fancy pins, and some clever casting are what it takes to build this tiny orrery. And patience — a lot of patience, too.

As model solar systems go, this one is exceptionally small. Its maker, [Mike] from Chronova Engineering, says it measures about 20 mm across and qualifies as the smallest orrery around. We can’t officiate that claim, but we’re not going to argue with it either. It’s limited to the Sun-Earth-Moon system, and while not as complete as some other models we’ve seen, it’s still exquisitely detailed. The gears that keep the Moon rotating 12.4 times around the Earth for each rotation of our home planet around the Sun are tiny, and take an abundance of watchmaking skill to pull off.

The video below shows the whole process, which is absolutely entrancing to watch. There are some neat tricks on display, from milling out the arms of the main wheel using a powered tailstock spindle to casting the Sun from resin in a silicone mold. The final model, with the model Earth and Moon spinning around the Sun on delicate brass wheels, is a visual treat.

We’ve seen some interesting stuff from Chronova Engineering lately, including this bimetallic tea timer.

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An Improved Spectrometer, No Lasers Required

May 27, 2024 by 23 Comments

Here at Hackaday, we love it when someone picks up the ball from a previous project and runs with it. That’s what we’re all about, really — putting out cool projects that just might stimulate someone else to extend and enhance it, or even head off in an entirely new direction. That’s how the state of the art keeps moving.

This DIY spectrometer project is a fantastic example of that ethos. It comes to us from [Michael Prasthofer], who was inspired by [Les Wright]’s PySpectrometer, a simple device cobbled together from a pocket spectroscope and a PiCam. As we noted at the time, [Les] put a lot of the complexity of his instrument in the software, but that doesn’t mean there wasn’t room for improvement.

[Michael]’s goals were to make his spectrometer a little easier to build, and to improve the calibration process and overall accuracy. To help with the former, he went with software correction of the color filter array on his Fuji X-T2. This has the advantage of not requiring a high-power laser and precision micropositioner to ablate the CFA, and avoids potentially destroying an expensive camera. For the latter, [Michael] delved deep into the theory behind spectroscopy and camera optics to develop a process for correlating the intensity of light along the spectrum with the specific wavelength at that location. He also worked a little machine learning into the process, training a network to optimize the response functions.

The result is pretty accurate spectra with no lasers required for calibration. The video below goes into a lot of detail and ends up being a good introduction to some of the basics of spectroscopy, along with the not-so-basics.

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Camera And Lens Repair Hack Chat

May 27, 2024 by 13 Comments

Join us on Wednesday, May 29 at noon Pacific for the Camera and Lens Repair Hack Chat with Anthony Kouttron!

Unlike the normies, most of us are pretty comfortable looking under the hood of just about anything electronic or mechanical. Whether it’s to effect a repair, make a modification, or just to take a look around, voiding warranties is what we do. A lot of us have hard limits, though, and will shy away from certain types of equipment. High voltages and radiation come to mind, as well as machines with lots of spinny bits that can devour your hands in a trice. One mustn’t be foolhardy, after all.

But one place that we’ve always feared to tread for some reason is camera equipment. Perhaps it has to do with all those impossibly tiny screws with subtly different lengths and the knowledge that putting the wrong screw in the wrong hole could have disastrous results. Or maybe it’s just the general fear that messing around with the insides of lenses could knock something slightly off-kilter and ruin the optics.

join-hack-chatWe’re certainly glad that Anthony Kouttron doesn’t share this trepidation. We recently featured a lens repair that he accomplished that was packed with tips and tricks for optical repairs. It turns out that Anthony has been repairing cameras for leisure since 2010, and has serviced both consumer and high-end cinema equipment — so he’s seen his fair share of broken camera bits. We’ve asked him to drop by the Hack Chat, so if you’ve been hesitant to dive into optical fixes, now might be your chance to learn about the dos and don’ts of camera and lens repair.

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 29 at 12:00 PM Pacific time. If time zones have you tied up, we have a handy time zone converter.