Ground Penetrating Radar For The Masses

Radar is a useful tool with familiar uses such as detecting aircraft and observing weather. It also has some less known applications, such as a technology known as ground-penetrating radar (GPR). Despite the difficulty of sending and receiving radio waves through solid objects, with the right equipment it’s possible to build a radar that works underground as well.

GPR is used often for detecting underground utilities, but also has applications in other fields such as archaeology and geology. For those people in these fields, a less expensive GPR was the priority of a group presenting at a 2017 National Institute of Telecommunications of Poland conference (pdf warning). The presentation goes into specific detail on how to build a GPR for around €600, much less than commercial offerings.

The presentation begins by highlighting the basics of GPR, then details the hardware bill of materials for the transmitting circuit, receiving circuit, and the DC power supplies. It also details the theory behind the software needed to get the circuit running properly, and has code as well. The processing is done on a 32-bit Mbed platform, and the rest of the GPR is built with easy-to-source components as well.

It’s always good to see useful hardware projects that bring costs of traditionally expensive equipment down to the grasp of average people. Even traditional radar systems are now available for hundreds of dollars, and we’ve even seen attempts at other GPR systems before as well.

Thanks to [Stefan] for the tip!

In Soviet Russia, Computer Programs You

We admire [Alex Studer’s] approach to schoolwork. His final assignment in his history class was to do an open-ended research project on any topic and — this is key — using any medium. He’d recently watched a video about how Tetris came from the former Soviet Union, and adding in a little eBay research set out to build a period-accurate Soviet computer replica. The post covers the technical details, but if you want to read the historical aspects the school paper is also online.

The first decision was what CPU to use and [Alex] picked the U880 which is a Soviet Z80. All the usual parts you would use with a Z80 have U880 equivalents, so that fleshed out the rest of the design. There were a few concessions made. Instead of a bulky analog monitor, the replica uses an LCD display. Instead of an audio cassette recorder, the new machine uses a CompactFlash socket. We don’t think those are bad decisions. He also replaced the Soviet EPROMs with modern parts. Although the original parts appeared to program correctly, they were unreliable in operation. [Alex] theorizes that his programmer did not generate enough programming voltage to fully program the cells, so they would pass at the low speeds used by the programmer, but not work in the actual circuit.

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Purge Buckets To Help With Multimaterial Printing

3D printing is cool, but most basic fused deposition printers just print in a single color. This means that if you want a prettier, more vibrant print, you need to paint or perform some other kind of finishing process. Multimaterial printers that can switch filaments on the fly exist, but they often have an issue with waste. [3DMN] decided to attempt building a purge bucket as a solution.

[3DMN] was previously familiar with using a purge block when running multimaterial prints. A basic block model is printed along side the actual desired part. The block is printed so that it is at the same layer height as the desired part, so the nozzle can purge cleanly without stringing plastic all over the print bed.

Tired of the waste, [3DMN] designed a purge bucket which moves with the Z-axis of his Geeetech A20M printer. The bucket attaches to the Z-axis with lock nuts and is always at the same height relative to the nozzle, regardless of the stage of printing. When a material change is required, the nozzle moves to the bucket, purges the filament, and then moves back to the print. The bucket features a 3mm silicone wiper to help ensure there is no material left clinging to the nozzle after the purge is complete, and aluminium tape which helps prevent the purged filament sticking to the walls of the bucket.

[3DMN] notes there’s also a speed increase for some prints, due to no longer needing to print purge objects along with the main part. The parts are available on Thingiverse for those of you wishing to experiment with your own setup.

Multimaterial printing can have some great visual results, and it’s great to see the community providing solutions to improve the process and reduce the waste involved.  We’ve also seen filament splicing, which is another unique approach to multimaterial prints. Video after the break.

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State Of The Art Big Mouth Alexa Bass

Hackers seem intent on making sure the world doesn’t forget that, for a brief shining moment, everyone thought Big Mouth Billy Bass was a pretty neat idea. Every so often we see a project that takes this classic piece of home decor and manages to shoehorn in some new features or capabilities, and with the rise of voice controlled home automation products from the likes of Amazon and Google, they’ve found a new ingredient du jour when preparing stuffed bass.

[Ben Eagan] has recently completed his entry into the Pantheon of animatronic fish projects, and while we’ll stop short of saying the world needed another Alexa-enabled fish on the wall, we’ve got to admit that he’s done a slick job of it. Rather than trying to convince Billy’s original electronics to play nice with others, he decided to just rip it all out and start from scratch. The end result is arguably one of the most capable Billy Bass updates we’ve come across, if you’re willing to consider flapping around on the wall an actual capability in the first place.

The build process is well detailed in the write-up, and [Ben] provides many pictures so the reader can easily follow along with the modification. The short version of the story is that he cuts out the original control board and wires the three motors up to an Arduino Motor Driver Shield, and when combined with the appropriate code, this gives him full control over Billy’s mouth and body movements. This saved him the trouble of figuring out how to interface with the original electronics, which is probably for the better since they looked rather crusty anyway.

From there, he just needed to give the fish something to get excited about. [Ben] decided to connect the 3.5 mm audio jack of an second generation Echo Dot to one of the analog pins of the Arduino, and wrote some code that can tell him if Amazon’s illuminated hockey puck is currently yammering on about something or not. He even added a LM386 audio amplifier module in there to help drive Billy’s original speaker, since that will now be the audio output of the Dot.

A decade ago we saw Billy reading out Tweets, and last year we presented a different take on adding an Alexa “brain” to everyone’s favorite battery powered fish. What will Billy be up to in 2029? We’re almost too scared to think about it. Continue reading “State Of The Art Big Mouth Alexa Bass”

Voja Antonic: Designing the Cube

Voja Antonic designed this fantastic retrocomputing badge for Hackaday Belgrade in 2018, and it was so much fun that we wanted to bring it stateside to the Supercon essentially unaltered. And that meant that Voja had some free time to devote to a new hardware giveaway: the Cube. So while his talk at Supercon in November was ostensibly about the badge, he just couldn’t help but tell us about his newer love, and some of the extremely clever features hidden within.

It’s funny how the hardware we design can sometimes reflect so much on the creator. Voja designed then-Yugoslavia’s first widely used home computer (and published the DIY plans in a magazine!). Thousands were built from their kits. The Galaksija was a Z80-based design with a custom BASIC that was just barely squeezed into the available 4K of ROM. So you shouldn’t be shocked that the retro-badge has a working keyboard and a nice BASIC on board.

But let’s jump ahead to the Cube, because that’s even more of a passion project. On the outside, they’re very simple devices, with only a USB port and a sweet diffused LED ring visible. Aesthetic? Minimalistic? Beautiful, honestly.
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Oops… Britain Launched A Satellite, But Who Remembers It?

Did you know Britain launched its first satellite after the program had already been given the axe? Me neither, until some stories of my dad’s involvement in aerospace efforts came out and I dug a little deeper into the story.

I grew up on a small farm with a workshop next to the house, that housed my dad’s blacksmith business. In front of the workshop was a yard with a greenhouse beyond it, along one edge of which there lay a long gas cylinder about a foot (300mm) in diameter. To us kids it looked like a torpedo, and I remember my dad describing the scene when a similar cylinder fell off the side of a truck and fractured its valve, setting off at speed under the force of ejected liquid across a former WW2 airfield as its pressurised contents escaped.

Everybody’s parents have a past from before their children arrived, and after leaving the RAF my dad had spent a considerable part of the 1950s as a technician, a very small cog in the huge state-financed machine working on the UK’s rocket programme for nuclear and space launches. There were other tales, of long overnight drives to the test range in the north of England, and of narrowly averted industrial accidents that seem horrific from our health-and-safety obsessed viewpoint. Sometimes they came out of the blue, such as the one about a lake of  highly dangerous liquid oxidiser-fuel mix ejected from an engine that failed to ignite and which was quietly left to evaporate, which he told me about after dealing with a cylinder spewing liquid propane when somebody reversed a tractor into a grain dryer.

Bringing Home A Piece Of History

The remains of the Black Arrow first and second stages, taken from the Skyrora promotional video.
The remains of the Black Arrow first and second stages, taken from the Skyrora promotional video.

My dad’s tales from his youth came to mind recently with the news that a privately-owned Scottish space launch company is bringing back to the UK the remains of the rocket that made the first British satellite launch from where they had lain in Australia since crashing to earth in 1971. What makes this news special is that not only was it the first successful such launch, it was also the only one. Because here in good old Blighty we hold the dubious honour of being the only country in the world to have developed a space launch capability of our own before promptly abandoning it. Behind that launch lies a fascinating succession of forgotten projects that deserve a run-through of their own, they provide a window into both the technological and geopolitical history of that period of the Cold War.

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Arduino Enters the Cloud

Love it or hate it, for many people embedded systems means Arduino. Now Arduino is leveraging its more powerful MKR boards and introducing a cloud service, the Arduino IoT Cloud. The goal is to make it simple for Arduino programs to record data and control actions from the cloud.

The program is in beta and features a variety of both human and machine interaction styles. At the simple end, you can assemble a dashboard of controls and have the IoT Cloud generate your code and download it to your Arduino itself with no user programming required. More advanced users can use HTTP REST, MQTT, Javascript, Websockets, or a suite of command line tools.

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