Author: Adil Malik

28 Articles

Draw On Your Lawn With This Autonomous Mower And RTK-GPS

August 16, 2020 by 9 Comments

The rise of open source hardware has seen a wide variety of laborious tasks become successfully automated, saving us humans a great deal of hassle.  Suffice to say, some chores are easier to automate than others. Take the classic case of a harmless autonomous vacuum cleaner that can be pretty dumb, bumping around the place to detect the perimeter as it traverses the room blindly with a pre-programmed sweeping pattern.

Now in principle, this idea could be extended to mowing your lawn. But would you really want a high speed rotating blade running rampant as it aimlessly ventures outside the perimeter of your lawn? The Sunray update to the Ardumower autonomous lawn mower project has solved this problem without invoking the need to lay down an actual perimeter wire. As standard consumer grade GPS is simply not accurate enough, so the solution involves implementing your very own RTK-GPS hardware and an accompanying base station, introducing centimeter-level accuracy to your mowing jobs.

RTK-GPS, also known as Carrier Phase Enhanced GPS, improves the accuracy of standard GPS by measuring the error in the signal using a reference receiver whose position is known accurately. This information is then relayed to the Ardumower board over a radio link, so that it could tweak its position accordingly. Do you need the ability to carve emojis into your lawn? No. But you could have it anyway. If that’s not enough to kick off the autonomous lawnmower revolution, we don’t know what is.

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Cheap And Effective Mosquito Trap Looks Like A Disco

August 3, 2020 by 34 Comments

Words cannot quite articulate the collective loathing humankind has for mosquitoes, and rightfully so! These parasite peddling, blood sucking little critters are responsible for a great deal of human suffering. Mosquito-borne diseases such as malaria still account for a significant proportion of human mortality, especially in under-developed parts of the world . So it’s no wonder that people try to reduce their numbers; see this latest $40 mosquito trap by [jacobsk]. (Video, embedded below.)

The idea is critically simple, opening up the potential for widespread deployment. The base and body of the trap are made out of three five-gallon buckets with a mini desk fan sandwiched in between, providing suction into the main trap bin. An opening is cut in the top bucket as a point of entry, and an old school incandescent blacklight is mounted in the centre, with just enough IR and UV output to entice these little vermin, who will definitely regret mistaking it for a black-light rave.

[jacobsk] also does a very good job of showing every step of its construction in his videos. Whilst this solution is purposefully low tech, check out this admittedly overcooked way of killing mosquitoes, with a laser turret.

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Trick From 1903 Makes An Old Monochrome TV Spit Some Colours

July 28, 2020 by 26 Comments

Its safe to say that colour television is taken for granted nowadays. Consumed by the modern marketing jargon of colour dynamic range, colour space accuracy and depth, it is easy to overlook the humble beginnings of image reproduction when simply reconstructing an image with the slightest hint of colour required some serious ingenuity and earned you a well deserved pat on the back!

[anfractuosus] revisited an old gem of a technique, first patented in 1903 and used it to successful make an old monochrome TV produce a colour image. The idea in essence, is actually similar to what cheap image sensors and LCDs still use today. Rather than relying on true RGB colour generation by individually integrating colour sources as AMOLED does, we take an easier route: Produce a simpler monochrome image where each colour pixel is physically represented by four monochrome sub-pixels, one for each colour component. Now light up each of the sub-pixels according to the colour information of your image and rely on an external colour filter array to combine and spit out the correct colours.

He first used some image processing to convert a standard colour video into the aforementioned monochrome sub-pixel representation. Next, a Bayer colour filter array was printed on some acetate sheets using an inkjet printer (the original inventors used potato starch!), which when overlaid on top of the monochrome monitor, magically result in colour output.

There are some problems associated with this technique, mainly to do with the difficulty in measuring the size of the TV pixels and then producing and perfectly aligning a filter sheet for it. You should check out how [anfractuosus] went about solving those issues.

So now you know a bit more about colour image generation, but how about colour TV transmission? Check out an earlier piece to learn more.

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Can A 3D Printer Print Better Filament For Itself?

July 20, 2020 by 21 Comments

3D printed parts are generally no way near the strength of an equivalent injection moulded part and techniques such as a sustained heat treatment, though effective usually distort the part beyond use.

[CNC Kitchen] was investigating the results (video, embedded below) of a recent paper, that described a novel ABS filament reinforced by a “star” shaped Polycarbonate core, an arrangement the authors claim is resilient to deformation during the annealing process often necessary to increase part strength. While the researchers had access to specialised equipment needed to manufacture such a composite material, [CNC Kitchen’s] solution of simply using his dual extruder setup to directly print the required hybrid filament is something we feel, strongly resonates with the now old school, RepRap “print your printer” sentiment.

The printed filament seems to have reasonable dimensional accuracy and passing the printed spool through a heater block without the nozzle attached, ensured there would be no obvious clogs. The rest of the video focuses on a very thorough comparison of strength and deformation between the garden variety Polycarbonate, ABS and this new hybrid filament after the annealing process. Although he concludes with mixed results, just being able to combine and print your own hybrid filament is super cool and a success in its own right!

Interested in multi-material filaments? Check out our article on a more conventional approach which does not involve printing it yourself!

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Reverse Engineering Teaches An Old Scope New Tricks

July 18, 2020 by 8 Comments

[PMercier] clearly loves his old Tektronix TDS3014 scope, which did however lack essentially modern connectivity such as an Ethernet port for control and a USB port for a convenient way to capture screenshots. So he decided to do some in-depth reverse engineering and design his own expansion card for it. The scope already has an expansion port and an expansion card, but given this model was first released in 1998, purchasing an OEM part was not going to be an option.

They don’t make ’em like they used to. Test equipment is today is built to last a decade — but usually lives on much longer. This is certainly true for the previous generations of kit. It’s no surprise that for most of us, hand-me-downs from universities, shrewd eBay purchasing, and even fruitful dumpster dives are a very viable way to attain useful and relevant test equipment. Now, while these acquisitions are more than adequate for the needs of a hobbyist lab, they are admittedly outdated and more to the point, inaccessible from a connectivity and communication standpoint. A modern lab has a very high degree of automated data acquisition and control over ethernet. Capturing screen dumps on a USB is a standard feature. These modern luxuries don’t exist on aging equipment conceived in the age of floppy disks and GPIB.

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X-Ray Sleuthing Unveils The Fake In Your Adaptors

July 15, 2020 by 36 Comments

Lets face it, the knock-off variety of our favourite adaptors, cables and accessories are becoming increasingly challenging to spot. We would be the first to admit, to have at some point, been stooped by a carefully crafted counterfeit by failing to spot the tell-tale yet elusive indicators such as the misplaced font face, the strategically misspelled logo or perhaps the less polished than expected plastic moulding and packaging. When you finally come around to using it, if you are lucky the item is still more or less functionally adequate, otherwise by now the inferior performance (if not the initial cost!) would have made it pretty obvious that what you have is infact a counterfeit.

[Oliver] recently found himself in a similar situation, after acquiring a seemingly original Lightning to Headphone Adaptor. Rather than dismay, [Oliver] decided to channel this energy into an excellent forensic investigation to uncover just what exactly made this imitation so deceptive. He began by comparing the packaging, printed typeface and the plastic moulding, all of which gave very little away. [Oliver] concluded that atleast superficially, the clone was rather good and the only way to settle this was to bring out the X-ray, of course!  

The resulting images of the innards make it blatantly obvious as to why the adaptor is indeed very fake. For a start, compared to the original adaptor, the clone hosts a far more thin BOM count! If you are really serious in getting some training to better spot counterfeits, check out a post we featured earlier on the subject!

Interactive CNC Foam Cutter Churns Out Abstract Art

July 11, 2020 by 3 Comments

Foam is certainly an indispensable raw material for various craft and construction projects. Any serious sculptor however, inevitably grows tired of grinding through a foam block using a simple preheated utensil. The next step up, is to assemble a simple but thoroughly effective hot wire cutting contraption, formed out of a thin guitar wire held taut on a “C” shaped mounting frame. Finally, the addition of some electronics to regulate the power delivery makes this simple tool useful for most settings.

[Freddie] has taken this basic idea a step further, by building a complete multi-axis CNC foam cutter intended as an interactive exhibit on computational art. The CNC has the traditional three Cartesian axes but the platform hosting the foam piece can also rotate, introducing an additional degree of freedom. As this is indented to be controlled by attendees, there is no G-code in the mix, rather the inputs of an Xbox controller are applied directly to the work piece.

What is very interesting is how the resulting tool path is visualised and displayed. [Freddie] explains that while the user input tool path could be generated and displayed as equivalent G-code, it does not capture and convey the inherent organic nature of the finished pieces. The solution [Freddie] came up with is to display the toolpath much like a series of musical notes!

We would have loved to have a go at this machine in person, but seeing that isn’t possible in the current circumstances, you can either build a simpler machine we featured earlier or [Freddie] could perhaps fire up a camera and let us control it via the interweb, with a live video feed ofcourse!

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