For a large proportion of the world’s population, it’s now winter, which means there’s plenty of rain and snow to go around. With the surrounding environment generally cooler and wetter than usual, it’s a great time to experiment with dangerous flame based projects, like this wrist mounted flame thrower.
It’s a build that does things in both a simple and complicated way, all at once. Fuel is provided by a butane canister with a nozzle that needs to be pressed to release the gas. A servo is used to push the canister into a 3D printed housing, releasing the gas into a pipe to guide the fuel towards the end of the user’s wrist. The fuel is then ignited by a heated coil of wire. The heated wire and the servo are both controlled by standard radio control gear typically seen on RC cars or buggies. Using the brushed speed controller to run the heated coil is particularly off-beat, but it does the job admirably.
Overall, it goes without saying that this build presents some serious risks of burns and other injuries. However, the fundamental premise is sound, and it does what it says on the tin with parts that could be readily found in the average junk box.
Originally intended as a way to stabilize sensitive instruments on ships during World War II, the Slinky is quite simply a helical spring with an unusually good sales pitch. But as millions of children have found out since the 1940’s, once you roll your Slinky down the stairs a few times, you’ve basically hit the wall in terms of entertainment value. So what if we told you there was yet another use for this classic toy that was also fun for a girl and a boy?
Before anyone gets out the pitchforks, admittedly this isn’t exactly a new idea. There are a few other write-ups online about people using a Slinky as a cheap antenna, such as this detailed analysis from a few years ago by [Frank Dörenberg]. There’s even rumors that soldiers used a Slinky from back home as a makeshift antenna during the Vietnam War. So this is something of an old school ham trick revived for the new generation of SDR enthusiasts.
Anyway, the setup is pretty simple. You simply solder the RF jack of your choice to two stretched out Slinkies: one to the center of the jack and one to outside. Then run a rope through them and stretch them out in opposite directions. The rope is required because the Slinky isn’t going to be strong enough when expanded to keep from laying on the ground.
One thing to keep in mind with a Slinky antenna is that these things are not exactly rated for outside use. Without some kind of treatment (like a spray on acrylic lacquer) , they’ll quickly corrode and fail. Though a better idea might simply to be to think of this as a temporary antenna that you put away when you’re done with. Thanks to the fact that the Slinky doesn’t get deformed even when stretching it out to maximum length, that’s relatively easy to accomplish.
We’ve all seen videos of Rubik’s cube champions who can solve the puzzle in less than 5 seconds. And there are cube-twisting robots that can solve the cube even faster, often in under a second. This Rubik’s cube solver is not one of those robots, but it’s still pretty cool.
The reason we like Dexter Industries’ “BricKuber” is not for its lightning speed — it takes a minute or two to solve the puzzle. What we like is the simplicity of the approach to manipulating the cube. Built from LEGO parts, including Mindstorms motors and a BrickPi controller, the BricKuber uses only two motors to work the cube. One motor powers a square turntable upon which the cube sits, while the other powers an arm that does double duty — it either clamps the cube so the turntable can rotate a layer, or it rakes the cube to flip it 90° on the turntable. With a Pi Cam overhead, the rig images all six faces, calculates a solution to the cube, and then flips and twists the cube to solve it. It’s simultaneously mind-boggling and strangely relaxing to watch.
All the code is open source, and we strongly suspect a similar and possibly faster robot could be built without the LEGO parts. You might even be able to build one with popsicle sticks and an Arduino.
How would you sell a computer to a potential buyer? Fast? Reliable? Great graphics and sound? In 1956, you might point out that it was somewhat smaller than a desk. After all, in those days what people thought of as computers were giant behemoths. Thanks to modern FPGAs, you can now have a replica of a 1956 computer — the LGP-30 — that is significantly smaller than a desk. The LittleGP-30 is the brainchild of [Jürgen Müller].
The original also weighed about 740 pounds, or a shade under 336 kg, so the FPGA version wins on mass, as well. The LGP-30 owed its relative svelte footprint to the fact that it only used 113 tubes and of those, only 24 tubes were in the CPU. This was possible, because, like many early computers, the CPU worked on one bit at a time. While a modern computer will add a word all at once, this computer — even the FPGA version — add each operand one bit at a time.
We sometimes forget that the things we think of as trivial today were yesterday’s feats of extreme engineering. Consider the humble pocket calculator, these days so cheap and easy to construct that they’re essentially disposable. But building a simple “four-banger” calculator in 1962 was anything but a simple task, and it’s worth looking at what one of the giants upon whose shoulders we stand today accomplished with practically nothing.
If there’s anything that [Cliff Stoll]’s enthusiasm can’t make interesting, we don’t know what it would be, and he certainly does the job with this teardown and analysis of a vintage electronic calculator. You’ll remember [Cliff] from his book The Cuckoo’s Egg, documenting his mid-80s computer sleuthing that exposed a gang of black-hat hackers working for the KGB. [Cliff] came upon a pair of Friden EC-132 electronic calculators, and with the help of [Bob Ragen], the engineer who designed them in 1962, got one working. With a rack of PC boards, cleverly hinged to save space and stuffed with germanium transistors, a CRT display, and an acoustic delay-line memory, the calculators look ridiculous by today’s standards. But when you take a moment to ponder just how much work went into such a thing, it really makes you wonder how the old timers ever brought a product to market.
As a side note, it’s great to see the [Cliff] is still so energetic after all these years. Watching him jump about with such excitement and passion really gets us charged up.
Printed circuit boards are a fundamental part of both of commercial electronic equipment and of the projects we feature here on Hackaday. Many of us have made our own, whether done so from first principles with a tank of etchant, or sent off as a set of Gerbers to a PCB fab house.
To say that the subject of today’s Retrotechtacular is the manufacture of printed circuit boards might seem odd, because there is nothing archaic about a PCB, they’re very much still with us. But the film below the break is a fascinating look at the process from two angles, both for what it tells us about how they are still manufactured, and how they were manufactured in 1969 when it was made.
Board artwork laid out at four-times actual size
Tektronix were as famous for the manufacturer of particularly high quality oscilloscopes back then as they are now. The Tektronix ‘scopes of the late 1960s featured several printed circuit boards carrying solid-state electronics, and were manufactured to an extremely high standard. The film follows the manufacturing process from initial PCB layout to assembled board, with plenty of detail of all production processes.
In 2017 you would start a PCB design in a CAD package, but in 1969 the was incredibly manual. Everything was transcribed by hand from a paper schematic to transparent film. Paper mock-ups of component footprints four times larger than actual size are placed on a grid, and conductors drawn in pencil on an overlaid piece of tracing paper. Then the pads and pattern of tracks are laid out using black transfers and tape on sheets of film over the tracing paper, one each for top and bottom of the board. A photographic process reduces them to production size onto film, from which they can be exposed and etched in the same way that you would in 2017.
Pantograph drilling machine uses a manually moved styuls on a template to drill six boards at once
Most of the physical process of creating a PCB has not changed significantly since 1969. We are shown the through-plating and gold plating processes in detail, then the etching and silkscreening processes, before seeing component installation and finally wave soldering.
What are anachronistic though are some of the machines, and the parts now robotised that were done in 1969 by hand. The PCB drilling is done by hand with a pantograph drill for small runs, but for large ones a fascinating numerically-controlled drilling rig is used, controlled by punched tape without a computer in sight. Component placement is all by hand, and the commentator remarks that it may one day be done by machine.
The film remains simultaneously an interesting look at PCB production and a fascinating snapshot of 1960s manufacturing. It’s probable that many of the Tek ‘scopes made on that line are still with us, they’re certainly familiar to look at from our experience at radio rallies.
His name may not ring a bell, but his handle will — Sprite_tm, a regular to these pages and to Hackaday events around the world. Hailing from The Netherlands by way of Shanghai, Jeroen Domburg dropped by the Hackaday Superconference 2017 to give a talk on a pet project of his: turning a Macintosh into, well, a pet.
You could say this is Jeroen’s second minification of vintage hardware. At last year’s Hackaday Superconference, he brought out the tiniest Game Boy ever made. This incredible hardware and software hack stuffs a complete Game Boy into something you can lose in your pocket. How do you top a miniature version of the most iconic video game system ever made? By creating a miniature version of the most iconic computer ever made, of course.
The tiny object in front of Jeroen in the title image is, in fact, a working Macintosh Plus that he built. Recreating mid-80’s technology using 2017 parts seems like it would be easy, and while it’s obviously easier than breaking the laws of physics to go the other direction, Jeroen faced some serious challenges along the way, which he goes into some detail about in his talk.
