It is good advice to change batteries in your fire alarms at least once a year. Even our low-power LCD calculators need new batteries from time to time. But at the University of Oxford, they have an electric bell that has been ringing essentially non-stop on one set of batteries for about 178 years! Is the energy crisis solved then? Perhaps not. The bells require a high voltage but very little current and the pair of batteries — piles in the parlance of 1840 — have kept the charge flowing for about 10 billion rings. As you can see in the video below, though, the ringing isn’t very vigorous.
How does it work? When you think of converting electrical power to mechanical motion you probably think of a motor, even though there are plenty of other transducers like speakers, muscle wires, and solenoids. Arguably the first device was electrostatic bells that were invented by a Scot named [Andrew Gordon] around 1742. [Ben Franklin] made them famous, though, so they are often called Franklin bells.
FranLab is closing down! Fran is one of the hardware greats, and she’s being evicted. If you’ve got 2000sqft of workshop space in Philly you’d like to spare, you know who to talk to. There will, probably, be a crowdfunding thing going up shortly, and we’ll post a link when it’s up.
The Parallax Propeller is probably one of the most architecturally interesting microcontrollers out there. It’s somewhat famous for being a multi-core chip, and is commonly used in VGA generation, reading keyboards, and other tasks where you need to do multiple real-time operations simultaneously. The Parallax Propeller 2, the next version of this chip, is in the works, and now there’s real silicon. Everything is working as expected, and we might see this out in the wild real soon.
Thought artistic PCBs were just a con thing? Not anymore, I guess. There has been a lot of activity on Tindie with the Shitty Add-Ons with [TwinkleTwinkie] and [Potato Nightmare] releasing a host of very cool badges for your badges. Most of these are Shitty Add-Ons, and there will be an update to the Shitty Add-On spec shortly. It’s going to be backwards-comparable, so don’t worry.
Unnecessary drama!?! In my 3D printing community?!? Yes, it’s true, there was a small tiff over the Midwest RepRap Festival this week. Here’s what went down. You got three guys. John, Sonny, and Steve. Steve owns SeeMeCNC, based in Goshen, Indiana. John worked for SeeMeCNC until this year, and has been the ‘community manager’ for MRRF along with Sonny. Seeing as how the RepRap Festival is the only thing that ever happens in Goshen, Steve wanted to get the ball rolling for next year’s MRRF, so he sent out an email, sending the community into chaos. No, there’s not some gigantic fracture in the 3D printing community, John and Sonny, ‘were just slacking’ (it’s five months out, dudes. plenty of time.), and Steve wanted to get everything rolling. No problem here, just a bunch of unnecessary drama in the 3D printing community. As usual.
We live in a world where anyone can build a CT machine. Yes, anyone. It’s made of laser-cut plywood and it looks like a Stargate. Anyone can build an MRI machine. Of course, these machines aren’t really good enough for medical diagnosis, or good enough to image anything that’s alive for that matter. This project for the Hackaday Prize is something else, though. It’s biomedical imaging put into a package that is just good enough to image your lungs while they’re still in your body.
The idea behind Spectra is to attach two electrodes to the body (a chest cavity, your gut, or a simulator that’s basically a towel wrapped around the inside of a beaker). One of these electrodes emits an AC signal, and the second electrode measures the impedance and phase. Next, move the electrodes and measure again. Do this a few times, and you’ll be able to perform a tomographic reconstruction of the inside of a chest cavity (or beaker simulator).
Hardware-wise, Spectra uses more than two electrodes, thirty-two on the biggest version built so far. All of these electrodes are hooked up to a PCB that’s just under 2″ square, and everything is measured with 16-bit resolution at a 160 kSPS sample rate. To image something, each electrode sends out an AC current. Different tissues have different resistances, and the path taken through the body will have different outputs. After doing this through many electrodes, you can use the usual tomographic techniques to ‘see’ inside the body.
This is a remarkably inexpensive way to image the interior of the human body. No, it doesn’t have the same resolution as an MRI, but then again you don’t need superconducting electromagnets either. We’re really excited to see where this project will go, and we’re looking forward to the inevitable project updates.
Those who were around for the pre-floppy days of computer mass storage were likely to have made the mistake of slipping a cassette tape containing data into a stereo tape deck. Instead of hearing the expected Awesome Mix, the speakers gave off an annoying bleat, warbling between two discordant tones and no doubt spoiling the mood.
What you likely heard was the Kansas City standard, an early attempt to provide the budding microcomputer industry with a mass-storage standard. It was successful enough that you can still find KCS tapes in need of decoding to this day. That job would be a snap with a microcontroller, which is exactly why [matseng] chose to do it the hard way and built a KCS decoder with nothing but discrete components.
The goal was to decode the frequency-shift-keyed (FSK) signal into an 8-bit parallel output, and maybe drive a seven-segment display as the characters came off the tape at a screaming 300 baud. Not an IC is in sight in the schematics; as [matseng] says, it’s nothing but “Qs, Rs, and Cs.” All the amps, flip-flops, and counters needed are built from a forest of transistors, and even the seven-segment display is a DIY affair of LEDs in a 3D-printed and hot-glue frame. The video below shows the display doing its best to show the alphanumeric characters encoded on the audio tape. And for who absolutely need a dose of Arduino, [matseng] used one along with a dead-bug low-pass filter to emulate KCS signals, for easier development.
We always appreciate hackers who take the road less traveled to arrive at a solution, but if you’re pressed for time to decode some KCS tapes, fear not – all you need is a PC and Audacity.
When featuring cool hacks repurposing one thing for something else, we prefer to focus on what we could get our hands on and replicate for ourselves. Not this one, though, as nobody else has the misfortune of being responsible for 2,000 square kilometers (772 square miles) of radioactive contaminated land like the government of Ukraine. Trying to make the best of what they have, they’ve just launched a pilot program working to put up solar power farms inside the Chernobyl Exclusion Zone.
This is sure to invite some jokes in the comments section, but the idea has merit. Thirty years of weather has eroded the worst aftermath of the Chernobyl explosion. That area is no longer immediately lethal and people have been making short visits. Spanning from safety inspectors, to scientists, to curious adventurers with questionable judgement making television shows. Supposedly, by following rules on what not to do, it’s possible to keep radiation exposure of a short visit down to the level experienced by frequent fliers. But that’s still too much radiation for long-term stay. That means no homes, office parks, or factories. No agriculture either, as plants and animals grown in the area should not be eaten.
So what’s left? That’s what Ukraine has been struggling with, as it tried to figure out something positive to offset the headaches of monitoring the area.
Well, next to the defunct power plant is the electric distribution infrastructure it used to feed into, and photovoltaic power generation requires little human oversight. Some maintenance will be required, but hopefully someone has worked out how to keep maintenance workers’ cumulative exposure to a minimum. And if this idea pans out, clean renewable energy would start flowing from the site of one of the worst ecological disasters of our era. That makes it a worthwhile hack on a grand scale.
If you know anyone who does crafts, they probably have a drawer with a few million beads loose and mixed together. You’ll sort them out one day, right? Probably not. Unless, of course, you build a robot to do the dirty work for you. That’s what [Kalfalfa] did, using some Phidgets boards, a camera and Open CV. You can see a video of the cardboard machine doing its thing below.
Maybe it is because we are more electronics-minded, but we were impressed with the mechanism to grab just one bead at a time from the hopper. If you watch the video, you’ll see what we mean. However, sometimes a bead jams and a magnetic sensor figures that out so the controller can reverse a bit and try again.
Nearly a decade ago my friend [Dru] gave me an unforgettable tour late at night of Stokes Croft, the inner suburb of Bristol known at the time for its counterculture and artistic scene. It’s a place dominated by building-sized graffiti and murals, and it has a particular association with the Bristolian street artist [Banksy]. If you’ve not seen a Banksy in the wild, the place to do it is by Bristol Saturday night street lighting to the sound of passing revelers and traffic on the A38.
[Banksy] is famous aside from his anonymity, for his pranks upon the art world. The (real) elephant in the room or the Dismalland theme park are his stock in trade, and you may have seen another prank of his in the news in the last day. One of his paintings, the 2006 Girl With A Balloon sold at auction for over a million quid, and as the gavel fell a hidden shredder in the picture frame sprang into life and partially shredded the canvas. The report suggests that a number of [Banksy]’s associates were present at the event, and that one of them was detained with a device that might have been a remote control trigger for the shredder. The quote from Sotheby’s Europe head of Contemporary Art, [Alex Branczik] says it all: “We got Banksy’d”.
The interior of the Banksy shredder frame, taken from a frame of the video.
[Banksy]’s cool and all that, but where’s the hack? The artist briefly put up a video with a few details, but aside from showing us a row of craft knife blades and a tantalizing but fleeting glimpse of a few equipment enclosures, it’s short on technical details. We can see what appears to be at least one motor, and those white boxes may be batteries, but that’s it.
This hasn’t stopped some fevered speculation as to how the feat was achieved. A home-made shredder would require a significant amount of readily available power, and since this one has seemingly lain undetected within the frame since 2006, that power source needs to have possessed both exceptional energy density and retention. We can’t imagine many consumer grade batteries in 2018 being able to retain a charge for twelve years, so how on earth did he do it? Our best guess is that a primary battery was involved, as anyone who has found a neglected Duracell in a box of electronics from their youth will tell you it’s not unknown for decent quality alkaline cells to live well beyond their shelf lives, and other chemistries are specifically designed with that property in mind. Even so, for the cells to power a receiver circuit in standby for so long would certainly tax their capabilities, so it has also been suggested that a concealed switch could have been flipped by a [Banksy] accomplice during the viewing phase to activate the system. There are still so many unanswered questions that it’s certainly piqued our technical curiosity. Sadly we don’t know [Banksy] to ask him how he did it, but we welcome speculation both informed and otherwise in the comments.
Our own [Joe Kim]’s tribute to the work in question.Meanwhile the piece itself lies half shredded and protruding from the base of the frame. On the face of it that’s ruined the painting as an artwork, but of course this is a Banksy. Normal rules seem not to apply, so the notoriety it has received will no doubt mean that its shredded remains are an artwork in themselves, and possibly even one worth more.
Banksy owners worldwide are no doubt now paying a huge amount more attention to the artist’s frames than previously, but Hackaday readers need not worry. Our London Unconference logo and stickers featured a [Joe Kim] homage to the Banksy in question, which we can guarantee does not incorporate an artist’s shredder.
![Our own [Joe Kim]'s tribute to the work in question.](https://hackaday.com/wp-content/uploads/2017/07/london.jpg)
