Hackaday Links: February 26, 2023

February 26, 2023 by Dan Maloney 32 Comments

It’s probably safe to say that most of us have had enough of the Great Balloon Follies to last the rest of 2023 and well beyond. It’s been a week or two since anything untoward was spotted over the US and subsequently blasted into shrapnel, at least that we know of, so we can probably put this whole thing behind us.

But as a parting gift, we present what has to be the best selfie of the year — a photo by the pilot of a U-2 spy plane of the balloon that started it all. Assuming no manipulation or trickery, the photo is remarkable; not only does it capture the U-2 pilot doing a high-altitude flyby of the balloon, but it shows the shadow cast by the spy plane on the surface of the balloon.

The photo also illustrates the enormity of this thing; someone with better math skills than us could probably figure out the exact size of the balloon from the apparent size of the U-2 shadow, in fact.

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RIP John Birkett, Parts Vendor Extraordinaire

May 20, 2022 by Jenny List 42 Comments

It is with sadness that we note the passing of John Birkett, proprietor of the legendary eponymous surplus radio and electronics store on an unassuming street in the British city of Lincoln, at the age of 93. He has been a fantastic source of esoteric parts and electronic assemblies for many decades, and though many of you from beyond where this is being written may never have heard of him the chances are that if you follow electronics enthusiasts from the UK you will have unwittingly seen parts which passed through his hands.

A typical Birkett advert from 1986 — Gateway to a world of wonders: a typical Birkett advert from 1986.

There was a time when surplus stores were a relatively common sight, given their window of opportunity by the huge quantity of post-war and Cold War military gear at knock-down prices. My town had one when I was a kid, but though it sold its share of electronic goodies it was more of a place for sturdy olive green outdoor wear or all the 1930s British military uniform items you might ever need. J. Birkett was different, as a purely electronics store the shop rapidly became the go-to place for both the most necessary and the most unexpected of parts.

His motto was “Not a piece of junk in sight”, and though as with much surplus equipment there is plenty of junk to be found it was his eye in managing to stock the junk which was most interesting and useful that made his selection special. Such was its reach that most of his customers including me never made it to Lincoln and the store itself, instead we came to him through his mail-order business and attendance at radio rallies. I fondly remember the anticipation of receiving a Birkett parcel, and I still have plenty of parts that came from him. An FM tuner converted for use as a 2 meter receiver is still in a box somewhere, and I’m pretty certain my storage unit still holds a pair of Pye Cambridge VHF transceivers he supplied.

According to Google the shop remains open, and we hope that state of affairs will continue. Surplus may not be what it once was, but we thank John Birkett for what he gave to generations of British hardware hackers. May he rest in peace.

Header image: Oliver Mills, (CC BY-SA 2.0).

Mystery Box Gives Up Its Patented Secrets

January 31, 2021 by Al Williams 21 Comments

[CuriousMarc] likes to go to surplus stores even though there are fewer of them around. On a recent trip, he found a box that had some parts he thought would work for a temperature controller project. It was marked Dial-A-Level and proudly proclaimed that it had a patent pending. The box was from the 1970s and [Marc] was wondering what the device was meant to do.

The device was a bit of a puzzle since it had three oddly-marked probe inputs. A search through the patent database revealed the device was a “capacitance probe for detecting moisture with very long cables.” The idea was to create a capacitor at the end of the cable and use the liquid as a dielectric. The sensor creates a 10 kHz sine wave it uses to excite the probe and an op amp measures the relative capacitive reactance of the probe versus a reference capacitor. The rest of the circuit is a comparator that reacts when the level is at a threshold.

We love seeing the old hand-drawn boards from that era. Component designations are in copper and there’s no solder mask visible. There was a clever application of a silicon controlled rectifiers and a relay to create a type of flip flop, that [Marc] explains.

Interestingly, the company that made the device, Expo Instruments, is still around and [Marc] contacted them. The actual patent holder replied and was amazed that [Marc] had possession of this antique. You can only wonder if anything you build today will wind up on whatever passes for YouTube three or four decades from now.

Capacitive sensing is quite versatile. Of course, there are many other ways to sense liquid level, too.

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Rolling Your Own LED Matrix Driver, With Copper Foil Tape To The Rescue

May 30, 2020 by Donald Papp 1 Comment

It all started when [Damien Walsh] got his hands on some surplus LED boards. Each panel contained 100 mini-PCBs hosting a single bright LED that were meant to be to be snapped apart as needed. [Damien] had a much better idea: leave them in their 20×5 array and design a driver allowing each LED to be controlled over WiFi. He was successful (a brief demo video is embedded down below after the break) and had a few interesting tips to share about the process of making it from scratch.

The first hurdle he ran into was something most of us can relate to; it’s difficult to research something when one doesn’t know the correct terms. In [Damien]’s case, his searches led him to a cornucopia of LED drivers intended to be used for room lighting or backlights. These devices make a large array of smaller LEDs act like a single larger light source, but he wanted to be able to individually address each LED.

Eventually he came across the IS32FL3738 6×8 Dot Matrix LED Driver IC from ISSI which hit all the right bases. Three of these would be enough to control the 100-LED panel; it offered I2C control and even had the ability to synchronize the PWM of the LEDs across multiple chips, so there would be no mismatched flicker between LEDs on different drivers. As for micontroller and WiFi connectivity, we all have our favorites and [Damien] is a big fan of Espressif’s ESP32 series, and used the ESP32-WROOM to head it all up.

LED pads bridged to copper tape, with Kapton (polyimide) tape insulating any crossovers.

The other issue that needed attention was wiring. Each of the LEDs is on its own little PCB with handy exposed soldering pads, but soldering up 100 LEDs is the kind of job where a little planning goes a long way. [Damien] settled on a clever system of using strips of copper tape, insulated by Kapton (a super handy material with a sadly tragic history.) One tip [Damien] has for soldering to copper tape: make sure to have a fume extractor fan running because it’s a much smokier process than soldering to wires.

A 3D-printed baffle using tracing paper to diffuse the light rounds out the device, yielding a 20 x 5 matrix of individually-controlled rectangles that light up smoothly and evenly. The end result looks fantastic, and you can see it in action in the short video embedded below.

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Psst – Wanna Buy A Control Panel From A Nuclear Power Station?

May 28, 2020 by Jenny List 73 Comments

Doing the rounds today is an interesting lot in an otherwise unexciting industrial dispersal auction in Lincolnshire, UK. On sale is an “Ex nuclear plant reactor control/monitoring system“, at the time of writing attracting the low low bid of £220 ($270), but we guess it will rise. Everyone who has watched Chernobyl (or maybe The Simpsons) is now gazing awestruck at a crescent of metal consoles covered in screens, buttons, and joysticks just waiting for a staff of white-coated technicians to pore over them.

Chernobyl Unit 3 control room (still active). [Source: IAEA Imagebank on Flickr CC-SA 2.0]

It’s a very cool lot indeed, but it raises more questions than it answers. The auction house has very little information indeed, so we’re left guessing, where did it come from? From this image showing the unit 3 control room at Chernobyl it’s obvious didn’t come from there (/s). Since it is for sale in the UK, and the country has decommissioned the majority of its first-generation reactors by now, so there is no shortage of candidates. But that intriguing possibility raises another question. Is it even a reactor control panel in the first place?

British civilian nuclear plants have tight security but they are hardly a secret, so plenty of photos are online showing their interiors. And in studying those we hit a problem, this panel doesn’t resemble any of the control panel images we can find. The first generation of Magnox (Magnetic Oxide Magnesium Non Oxidising) plants had panels covered in analogue dials and chart recorders so it’s unlikely to be one of those. The second-generation AGR (Advanced Gas-cooled Reactor) stations had similarly complex panels, and it’s evidently not one of them.

Looking closely at the photos it becomes apparent that there are a lot of camera controls and monitors, and even what looks like a uMatic video recorder. It’s definitely nuclear-related and the 1980s look of it suggests maybe it could have come from an Advanced Gas-Cooled Reactor (AGR) station, but could it be a little closer to Sector 7G than the centre of the action? Is it a video monitoring console used to keep a physical eye on its operation?

Be careful if you bid, you could end up with a rather cool but absurdly large 1980s CCTV system. Can any of our readers shed any light on the matter?

Thanks [Gregg “Cabe” Bond] for the tip.

Hackaday Links: March 15, 2020

March 15, 2020 by Dan Maloney 21 Comments

Just a few weeks ago in the Links article, we ran a story about Tanner Electronics, the Dallas-area surplus store that was a mainstay of the hacker and maker scene in the area. At the time, Tanner’s owners were actively looking for a new, downsized space to move into, and they were optimistic that they’d be able to find something. But it appears not to be, as we got word this week from James Tanner that the store would be shutting its doors after 40 years in business. We’re sad to see anyone who’s supported the hardware hacking scene be unable to make a go of it, especially after four decades of service. But as we pointed out in “The Death of Surplus”, the center of gravity of electronics manufacturing has shifted dramatically in that time, and that’s changed the surplus market forever. We wish the Tanner’s the best of luck, and ask those in the area to stop by and perhaps help them sell off some of their inventory before they close the doors on May 31.

Feel like getting your inner Gollum on video but don’t know where to begin? Open source motion capture might be the place to start, and Chordata will soon be here to help. We saw Chordata as an entry in the 2018 Hackaday Prize; they’ve come a long way since then and are just about to open up their Kickstarter. Check out the video for an overview of what Chordata can do.

Another big name in the open-source movement has been forced out of the organization he co-founded. Eric S. Raymond, author of The Cathedral and the Bazaar and co-founder and former president of the Open Source Initiative has been removed from mailing lists and banned from communicating with the group. Raymond, known simply as ESR, reports that this was in response to “being too rhetorically forceful” in his dissent from proposed changes to OSD, the core documents that OSI uses to determine if software is truly open source. Nobody seems to be saying much about the behavior that started the fracas.

COVID-19, the respiratory disease caused by the newly emerged SARS-CoV-2 virus, has been spreading across the globe, causing panic and claiming lives. It’s not without its second-order effects either, of course, as everything from global supply chains to conferences and meetings have been disrupted. And now, coronavirus can be blamed for delaying the ESA/Russian joint ExoMars mission. The mission is to include a Russian-built surface platform for meteorological and biochemical surveys, plus the ESA’s Rosalind Franklin rover. Program scientists are no longer able to travel and meet with their counterparts to sort out issues, severely crimping productivity and forcing the delay. Social distancing and working from home can only take you so far, especially when you’re trying to get to Mars. We wonder if NASA’s Perseverance will suffer a similar fate.

Speaking of social distancing, if you’ve already decided to lock the doors and hunker down to wait out COVID-19, you’ll need something to keep you from going stir crazy. One suggestion: learn a new skill, like PCB design. TeachMePCB is offering a free rigid PCB design course starting March 28. If you’re a newbie, or even if you’ve had some ad hoc design experience, this could be a great way to productively while away some time. And if that doesn’t work for you, check out Bartosz Ciechanowski’s Gears page. It’s an interactive lesson on why gears look like they do, and the math behind power transmission. Ever wonder why gear teeth have an involute shape? Bartosz will fix you up.

Stay safe out there, everyone. And wash those hands!

Hackaday Links: February 2, 2020

February 2, 2020 by Dan Maloney 17 Comments

Is it just me or did January seem to last for about three months this year? A lot has happened since the turn of the decade 31 days ago, both in the normie world and in our space. But one of the biggest pieces of news in the hacker community is something that won’t even happen for four more months: Hackaday Belgrade. The annual conference in Hackaday’s home-away-from-home in Serbia was announced, and as usual, one had to be a very early bird to score discount tickets. Regular tickets are still on sale, but I suspect that won’t last long. The call for proposals for talks went out earlier in the month, and you should really consider standing up and telling the world what you know. Or tell them what you don’t know and want to find out – there’s no better way to make connections in this community, and no better place to do it.

Someone dropped a tip this week about the possible closing of Tanner Electronics, the venerable surplus dealer located in Carrollton, Texas, outside of Dallas and right around the corner from Dallas Makerspace. The report from someone visiting the store is that the owner has to either move the store or close it down. I spoke to someone at the store who didn’t identify herself, but she confirmed that they need to either downsize or close. She said they’re actively working with a realtor and are optimistic that they’ll find a space that fits their needs, but the clock is ticking – they only have until May to make the change. We covered Tanner’s in a 2015 article on “The Death of Surplus”. It would be sad to lose yet another surplus store; as much as we appreciate being able to buy anything and everything online, nothing beats the serendipity that can strike walking up and down aisles filled with old stuff. We wish them the best of luck.

Are you finding that the smartphone in your pocket is more soul-crushing than empowering? You’re not alone, and more and more people are trying a “digital detox” to free themselves from the constant stimulation. And there’s no better way to go about this than by turning your smartphone into a not-so-smart phone. Envelope, a paper cocoon for your phone, completely masks the screen, replacing it with a simple printed keypad. A companion app allows you to take and make phone calls or use the camera, plus provides a rudimentary clock, but that’s it. The app keeps track of how long you can go before unwrapping your phone and starting those sweet, sweet dopamine hits again. It reminds us a bit of the story we also saw this week about phone separation anxiety in school kids, and the steps schools are taking to mitigate that problem.

We saw a lot of articles this week on a LoRaWAN security vulnerability. The popular IoT network protocol has been billed as “secure by default”, but a white paper released by cybersecurity firm IOActive found a host of potential attack vectors. Their main beef seems to be that client devices which are physically accessible can be reverse engineered to reveal their encryption keys. They also point out the obvious step of taking the QR code off of client devices so an attacker can’t generate session keys for the device.

And finally, the mummy speaks! If you ever wondered what the voice of someone who lived 3,000 years ago sounded like, wonder no more. Using computed tomography (CT) data, scientists in the UK and Germany have recreated the vocal tract of Nesyamun, an Egyptian scribe and priest from the time of pharaoh Rameses XI. He died in his mid-50s, and his mummified remains have been studied since the 1800s. CT data was used to 3D-print Nesyamun’s larynx and nasopharynx, which was then placed atop a “Vocal Tract Organ”, possibly the strangest musical instrument in existence. The resulting vowel-like utterance is brief, to say the least, but it’s clear and strong, and it’s pretty impressive that we can recreate the voice of someone who lived and died three millennia ago.