Of all the horrors visited upon a warrior, being captured by the enemy might count as the worst. With death in combat, the suffering is over, but with internment in a POW camp, untold agonies may await. Tales of torture, starvation, enslavement and indoctrination attend the history of every nation’s prison camps to some degree, even in the recent past with the supposedly civilizing influence of the Hague and Geneva Conventions.
But even the most humanely treated POWs universally suffer from one thing: lack of information. To not know how the war is progressing in your absence is a form of torture in itself, and POWs do whatever they can to get information. Starting in World War II, imprisoned soldiers and sailors familiar with the new field of electronics began using whatever materials they could scrounge and the abundance of time available to them to hack together solutions to the fundamental question, “How goes the war?” This is the story of the life-saving radios some POWs managed to hack together under seemingly impossible conditions.
Benchmarks often get criticized for their inability to perfectly model the real-world situations that we’d like them to. So take what follows in the limited scope that it’s intended, and don’t read too much into it. [Joonas Pihlajamaa]’s experiments with toggling a hardware pin as fast as possible on different single-board computers can still show us something.
The take-home result won’t surprise anyone who’s worked with a single-board computer: the higher-level interfaces are simply slow compared to direct memory-mapped GPIO access. But really slow. We’re talking around 5 kHz from Python or any of the file-based interfaces to the pins versus 3 MHz for direct access. Worse, as you’d expect when a non-realtime operating system is in the middle, there are glitches on the order of ten milliseconds with all the file-based methods.
This test only tells us so much, though, and it’s not really taking advantage of the BeagleBone Black’s ace in the hole, the PRUs — onboard hardware processors that bring real-time IO capabilities to the system. We’d like to see a re-write of the code to take advantage of libpruio, for instance. A 20 MHz square wave is a piece of cake with the PRUs.
Of course, it’s not interacting, which is probably in the spirit of the benchmark as written. But if raw hardware speed on a BeagleBone is the goal, it’s likely that the PRUs are going to feature prominently in the solution.
Smart Energy GB are the organisation campaigning for the roll-out of smart energy meters in the UK. Publicizing smart meters and making traditional electricity and gas meters look obsolete is part of their mission, and towards the end of last year they came up with a novel idea. “Requiem for Meters”, is a piece of orchestral music performed on instruments made from old gas and electricity meters, and recorded by the Royal Philharmonic Orchestra at the famous Abbey Road Studios in London.
The old meters serve as much as artworks in some of the instruments as they do a function. As far as we can see for example the gas meter violins are electric instruments rather than acoustic, the meter serving only as the physical body of the instrument rather than as an acoustic cavity in the way the body of a traditional violin does. The wind instruments seem to incorporate the cavity of a gas meter in their construction though and the percussive instruments are very much dependent on the properties of the meters themselves, though we’ll leave it to the reader to decide whether the resulting sound is one you’d want regularly on your hi-fi.
The video below the break shows some of the background to the piece, though sadly not as much instrument building detail as we’d like.
[luca] has always wanted a flying robot, but despite the recent popularity of quadcopters and drones [luca] has never seen a drone that is truly autonomous. Although sometimes billed as autonomous, quadcopters and fixed wing aircraft have always had someone holding a remote, had to stay in a controlled environment, or had some off-board vision system.
Since [luca] is building a coaxial copter – something that looks like a ducted fan with a few vanes at the bottom – there will be control issues. Normal helicopters use the pitch of the blades and the torque produced by the tail rotor to keep flying straight. A quadcopter uses two pairs of motors spinning in opposite directions to stay level. With just two rotors mounted on top of each other, you would think [luca]’s coaxial copter is an intractable problem. Not so; there are bizarre control systems for this type of flying machine that make it as nimble in the sky as any other helicopter.
The design of this flying robot is a bit unlike anything on the market. It looks like a flying ducted fan, with a few electronics strapped to the bottom. It’s big, but also has the minimum number of rotors, to have the highest power density possible with current technology. With a few calculations, [luca] predicted this robot will be able to hoist an IMU, GPS, ultrasonic range finder, optical flow camera, and a LIDAR module in the air for about fifty minutes. That’s a remarkably long flight time for something that hovers, and we can’t wait to see how [luca]’s build turns out.
Want to play around with the ESP8266? You’ll need a breadboard adapter, which allows you to connect the ESP8266 to a breadboard as you refine your design. Sure, you could just buy one, but where’s the fun in that?
[Markus Ulsass] designed a simple breadboard adapter for his ESP8266 that can be easily etched and built at home, but which has most of the features of the commercial versions. His adapter features a voltage regulator that can handle anything up to 7 volts and which has reverse polarity protection and a reset switch that puts the ESP8266 into flash mode, where it can be reprogrammed.
In the US, we don’t hear much about computing from beyond the Anglosphere. We’ve seen some home computer clones from behind the iron curtain, but getting any information about them is hard. If you find an old keyboard with a QWERTZ layout, or even a few Cyrillic characters, in the States, it’s a rarity. To date, the only French computer on Hackaday is an old Minitel dumb terminal. To help rectify this, [Jeremie Marsin], [Thierry Mazzoleni], and [Jean Paul Mari] from Quebec brought the best of the French computing revolution of the 1980s along to this year’s Vintage Computer Festival East
The evolution of the reigning champion of this exhibit begins with the Micronique Victor Lambda, a licensed copy of a purely American computer, the Interact Home Computer System. This computer featured a 2 MHz 8080A, 8 or 16 kB of RAM, and was quickly discontinued. The French company Micronique quickly bought the original designs and remarketed the computer in France.
In a few short years, Micronique took this design and turned it into the Hector. This machine featured a 5 MHz Z80, 48 kB of RAM, high resolution graphics (243×231 at four colors) and included BASIC and Forth interpreters.
The Victor and Hector were the best home computers at the time, but for every Commodore or Apple, you need a ZX Spectrum. France’s version of this tiny computer with a terrible keyboard was the Matra Alice 32, a computer with a 1 MHz 6803, 16kB of Ram, and a real 80×25 text mode. The Alice is heavily based on the American TRS-80 MC-10, with a SCART connector and an AZERTY keyboard.
The weirdest computer [Jeremie], [Thierry], and [Jean Paul] brought out? That would be the Excelvision EXL100. The 1980s, for better or worse, were the times of the Z80 and 6502. The EXL100 was running something completely different. This home computer used a TMS7020 CPU from Texas Instruments, a speech synthesizer, and a wireless keyboard. Very strange for the time and relatively inexpensive; in 1984 this computer cost only ₣3190, or about $550 USD.
[Jeremie], [Thierry], and [Jean Paul] had an exhibit that presented the best the Francosphere had to offer to the computing world in the 80s and 90s. We haven’t seen enough early computers from outside the US, so we’re happy to have met these guys at the 11th annual Vintage Computer Festival East.
On of our favorite science DIY YouTube channels, [NightHawkInLight] shows us how he made this awesome cannon — with interchangeable cannon cartridges! It even has a bit of a steampunk feel to it.
Nitrocellulose, or flash cotton as it’s more commonly known, is used by magicians for fireball magic tricks. Similar to flash paper, it burns up very fast and leaves almost no ash or residue. Creating the fireball effect is as simple as igniting it inside a tube — expanding gases take care of launching it out quite violently.
All the action is in the 3/4″ copper tube cartridges that come complete with home-made glow-plugs made from nichrome wire harvested from a broken hairdryer. These interchangeable cartridges allow [NightHawkInLight] to load up ahead of time and fire them off in quick succession.