How to sell your car on Junk Mail

Are you wondering how to sell your car online? There’s a quick and easy option. Place a FREE ad on Junk Mail and connect with potential car buyers across South Africa. Follow the steps below to list your car on Junk Mail.

Here’s how to sell your car on Junk
Mail:

Time needed: 5 minutes.

  1. Complete the ‘Advertiser Details’ section

    a) Enter your email address. If the email field is already filled in, it’s because the browser you’re using remembers you.

    b) Enter your WhatsApp contact number. The green checkbox is automatically ticked to enable WhatsApp on your advert, but if you don’t want WhatsApp enabled, you can untick this box. Please enter the WhatsApp number without spaces in between.

    c) If you have an additional number you would like to add (that is not your WhatsApp number), please click on ‘Add Contact Number’ and fill in your name and contact number. Please enter the contact number without spaces in between.

    If you are advertising as a business, please click on ‘Add Contact Number’ and tick the box for ‘Business Owners’ in the grey block. Enter Advertiser Details | Junk Mail Ad Placement

  2. Select a category and subcategory

    a) Select ‘Vehicles’ under ‘Choose a Category’.

    b) After clicking on ‘Vehicles’, it will give you a list of options to choose from below your selection. You can then select ‘Cars’. Select the vehicles category on Junk Mail

  3. Fill in the vehicle’s details

    After you’ve selected the subcategory, you’ll need to provide the details of the vehicle that you’re selling.

    a) Select the make of your vehicle, e.g. BMW.

    b) Select the model of your vehicle, e.g. 3 Series

    c) Select the model variant, e.g. 335i Convertible

    d) Select the colour of the vehicle, e.g. Black

    e) Type the mileage in km. Please enter the numbers without spaces in between.
    Mileage is the number of kilometres your car has travelled. You can find the mileage on your car’s dashboard. Your car will either have a mechanical odometer, a digital odometer or it will display your mileage on the dashboard behind the steering in newer vehicles. An odometer can usually be found above, below or next to the km/h counter.

    f) Type in the year model for your vehicle. Please note that this is the year the vehicle was manufactured and not the year you purchased the vehicle.

    g) Select your ad type/intention. You can choose from for sale, for rent, on auction, wanted, contact me, and to swop.

    h) Select the condition of your vehicle. You can choose from used, new or demo.

    i) Add in a description of the vehicle. You’ll need to write at least one sentence.
    A description of the vehicle is extremely important. The more information you can provide about the vehicle’s condition and features, the better since it helps people find it. You can mention things like upgraded mags, leather or material upholstery, service and accident history, engine performance, safety features, modifications made and more. You should also explain why you’re selling the car. It’s important to be honest and transparent and mention as much information as possible about the vehicle.

    j) Add the region where you’re selling the vehicle. You can select your province, city and suburb. Fill in the vehicle's details on ad placement | Junk Mail

  4. Upload photos of the vehicle you’re selling

    Complete your ad by adding images of your vehicle. Select the “Choose photos to upload” button or drag and drop the images into the box.

    a) The minimum image resolution accepted is 300 x 200 pixels.

    b) You can add up to 20 images on your advert.

    c) Use high-quality photos that are taken with good, natural lighting.

    d) Make sure the buyer can see the vehicle from all angles, interior and exterior. Also, take a photo of the dashboard in order for the buyer to see the mileage on the vehicle. Add photos to your car advert on Junk Mail

  5. Submit your advert

    Click the big green button at the bottom of your form and submit your advert.

    If you’ve clicked ‘Preview’, you’ll see that at the top of the preview page you can choose to edit or submit your advert. Submit your car advert on Junk Mail

Bonus Tips:

  • If you accidentally close the page or your browser without completing your ad, an email will be sent to you prompting you to complete your advert. It saves your progress as you fill in the form, so you can pick up where you’ve left off if something unexpected happens.
  • You can increase your chances of getting interaction with your advert by completing all the sections of the form. Incomplete adverts that don’t have images are less likely to attract the attention of potential buyers.
  • Check your spelling and grammar. Poorly written adverts are a deterrent to potential buyers.
  • If you’re selling more than one vehicle, create an advert for each one. It will help users find your advert when they search for it on the site or search engines.
  • Required fields will be marked with a red *. This means you cannot submit your advert without filling in these fields. If you try to submit your vehicle advert while one of those fields are incomplete, it will take you back to the first empty field and highlight that field in red.
Fill in all your details on the ad placement form | Junk Mail

Now that you know how to sell your car online, you can visit Junk Mail and place a FREE advert, quickly and easily.

Bright White Night Light Fights E-Waste

E-waste is a gigantic problem, and it can seem impossible as a lone individual to make any kind of dent in it. But [akshar1101] is trying to do their part by looking past the defective aspects of broken, discarded electronics to draw out the possibilities of what’s left.

This friendly night light is made from the PCBs of four broken Nokia 5110 LCD modules. The screens were all toast, but the nice white LEDs that used to light them from the sides work just fine. [akshar1101] cleverly tied all the LED and GND lines together with single right-angle header pins. To power the LEDs, they wired up a JST receptacle to one of the PCBs and connected a 3.7 V lithium battery pack that sits underneath. [akshar1101] diffused the piercing white lights into a soft glow with two pieces of acrylic.

We love to see electronic components get saved from landfills, especially when they can be turned into something useful and beautiful. Something about the traces on these boards makes them visually interesting to us — it’s that little hiccup that interrupts otherwise parallel lines.

If all of your 5110 LCDs are in working order, you could spice one of them up with an RGB backlight.

source https://hackaday.com/2020/08/31/bright-white-night-light-fights-e-waste/

100% Printed Flashlight: Conductive Filament and Melted-in Leads

Conductive filament isn’t an ideal electrical conductor, but it’s a 3D-printable one and that’s what makes [Hercemer]’s 3D-printed flashlight using conductive filament work. Every part of the flashlight is printed except for the 9 volt battery and LEDs. Electrically speaking, the flashlight is a small number of LEDs connected in parallel to the terminals of the battery, and turning it on or off is done by twisting or loosening a cap to make or break the connection.

The main part of the build is a 3D-printed conductive cylinder surrounded by a printed conductive ring with an insulator between them. This disk- or pad-shaped assembly forms not only the electrical connection between the LEDs and battery terminals, but also physically holds the LEDs. To attach them, [Hercemer] simply melts them right in. He uses a soldering iron to heat up the leads, and presses them into the 3D-printed conductive block while hot. The 9 V battery’s terminals contact the bottom when the end cap is twisted, and when they touch the conductive assembly the flashlight turns on.

3d Printed Flashlight Using Conductive Filament Assembly Video 1 3 Screenshot
3d Printed Flashlight Using Conductive Filament Assembly Video 1 21 Screenshot
3d Printed Flashlight Using Conductive Filament Assembly Video 1 42 Screenshot

Anticipating everyone’s curiosity, [Hercemer] measured the resistance of his conductive block and measured roughly 350 ohms when printed at 90% infill; lower infills result in more resistance. You can see a video of the assembly and watch the flashlight in action in the video, embedded below.

Heat-setting of the LED leads is clever, and allows a variety of LEDs to be mounted as needed. It’s a lot like brass heat set inserts, which work well with 3D printed plastics and could themselves make a good electrical connection in a similar build.

source https://hackaday.com/2020/08/31/100-printed-flashlight-conductive-filament-and-melted-in-leads/

100% Printed Flashlight: Conductive Filament and Melted-in Leads

Conductive filament isn’t an ideal electrical conductor, but it’s a 3D-printable one and that’s what makes [Hercemer]’s 3D-printed flashlight using conductive filament work. Every part of the flashlight is printed except for the 9 volt battery and LEDs. Electrically speaking, the flashlight is a small number of LEDs connected in parallel to the terminals of the battery, and turning it on or off is done by twisting or loosening a cap to make or break the connection.

The main part of the build is a 3D-printed conductive cylinder surrounded by a printed conductive ring with an insulator between them. This disk- or pad-shaped assembly forms not only the electrical connection between the LEDs and battery terminals, but also physically holds the LEDs. To attach them, [Hercemer] simply melts them right in. He uses a soldering iron to heat up the leads, and presses them into the 3D-printed conductive block while hot. The 9 V battery’s terminals contact the bottom when the end cap is twisted, and when they touch the conductive assembly the flashlight turns on.

3d Printed Flashlight Using Conductive Filament Assembly Video 1 3 Screenshot
3d Printed Flashlight Using Conductive Filament Assembly Video 1 21 Screenshot
3d Printed Flashlight Using Conductive Filament Assembly Video 1 42 Screenshot

Anticipating everyone’s curiosity, [Hercemer] measured the resistance of his conductive block and measured roughly 350 ohms when printed at 90% infill; lower infills result in more resistance. You can see a video of the assembly and watch the flashlight in action in the video, embedded below.

Heat-setting of the LED leads is clever, and allows a variety of LEDs to be mounted as needed. It’s a lot like brass heat set inserts, which work well with 3D printed plastics and could themselves make a good electrical connection in a similar build.

source https://hackaday.com/2020/08/31/100-printed-flashlight-conductive-filament-and-melted-in-leads/

Grasp Kotlin’s Coroutines With This Short Tutorial

Kotlin is a relatively new programming language; a derivative of Java with lots of little handy functional bits such as coroutines. [Foalyy] is porting an app to Android and learning Kotlin at the same time, and after wrapping their mind around coroutines, has written up a concise five-part tutorial on them.

Coroutines in Kotlin are a way to simplify writing asynchronous code, which is code that doesn’t necessarily execute in the order it is written. Coroutines are like light-weight threads that can be launched and managed easily, making it simpler to bridge together blocking and non-blocking code. (However, coroutines are not threads. They are more akin to suspending functions that play very well together.)

[Foalyy] found that the official Kotlin documentation on coroutines went into great detail on how coroutines function, but wanted a more bottom-up approach to understanding how they work and can be used. Luckily for anyone who thinks the same way, [Foalyy] wrote it all up and begins with a great recap of important elements, but if you prefer you can jump straight to the examples.

Kotlin has been around for a while, and readers with sharp memories may recall it was featured in this excellent introduction to what neural networks are and how they work.

source https://hackaday.com/2020/08/31/grasp-kotlins-coroutines-with-this-short-tutorial/

Something To Look Forward To: MCH2021 Call For Participation

As we stare dejectedly at our screens and consider what might have been during the 2020 summer that didn’t quite happen, here’s a little something to look forward to in a future where the COVID-19 pandemic will with any luck be much less of a threat. We have have had precious little in the way of events in 2020, but the call for participation has been announced for one of the largest planned for 2021. MCH2021 will be big European summer camp of next year, and is scheduled for the 6th to the 10th of August at Scoutinglandgoed Zeewolde in the Netherlands province of Flevoland. It will be the latest in a long line of such events going back to 1989, and with such a track record we know it’s going to be a good one.

We know that among our community are many people who’ll be interested in going to MCH, and that each and every one of you will have some fascinating insights that others would love to hear about. The challenge of the MCH orga is to bestow upon you the courage to stand up in front of your peers and talk about it, and from our experience here at Hackaday we’d say that an event such as this one makes for a very good place to give speaking a try. As always they’re interested in all the cool stuff that comes from our diverse community, but to help you along they’ve suggested a theme. Recent events have it’s fair to say presented a challenge to the world, and in that light they state that “we are especially looking for content that is about our ability to recover from extreme events of whatever nature”. We look forward to seeing you there.

source https://hackaday.com/2020/08/30/something-to-look-forward-to-mch2021-call-for-participation/

Sudden Death Rainbow Sorting Game Reveals Your True Colors

When [marzsman]’s eight-year-old daughter thought up a game they could play together involving rainbows, he was all ears. She is a certified rainbow expert, after all. They had a few R&D sessions and came up with a rainbow sorting speed trial game that looks fun to play and fairly easy to build.

Press that blue button on the side, and the RGB LEDs along the top are put in randomized order. The object of this game is simple — just sort the rainbow before the other player by pressing each LED’s corresponding arcade button. Whoever sorts faster is rewarded with a rainbow animation behind their set of way-cool clear buttons.

Inside the laser-cut box is an Espruino, which is a handy little microcontroller that speaks JavaScript. All of the arcade buttons are wired up as a key matrix. The astute among you have noticed there is six of everything, and that’s because indigo light is too hard to distinguish from blue. Check out the intense gameplay after the break.

If [marzsman]’s daughter wants to learn computer science, rainbows are good for that, too.

source https://hackaday.com/2020/08/30/__trashed-38/

Hackaday Links: August 30, 2020

Tech history is rife with examples of bizarre product demos, but we’ve got to think that Elon Musk’s Neuralink demo this week will have to rank up there with the weirdest of them. Elon’s job here was to sell the proposition that having a quarter-sized plug removed from your skull by a surgical robot and having it plunge 1,024 tiny wires into your gray matter will be totally normal and something that all the cool kids will be doing someday. We watched the 14-minute supercut of the demo, which went on for considerably longer than that due to the realities of pig wrangling, and we remain unsold on the technology. Elon selling it as “a Fitbit in your skull, with tiny wires” probably didn’t help, nor did the somewhat terrifying appearance of the surgical robot needed to do the job. On the other hand, Gertrude the Bionic Pig seemed none the worse for her implant, which was reportedly wired to her snout and sending data wirelessly. The demonstration of reading joint positions directly from the brain was honestly pretty neat. If you want to dive deeper into Neuralink, check out Maya’s great article that separates fact from science fiction.

Jerry Carr, NASA astronaut and commander of the third and final crewed Skylab mission, passed away this week at the age of 88. Carr’s Skylab 4 mission was record-breaking in 1974, with the three astronauts living and working in the orbiting workshop for 84 days. The mission contributed a vast amount of information on space medicine and the human factors of long-duration spaceflight. Carr retired from NASA in 1977 and had a long career as an engineer and entrepreneur. It’s sad to lose yet another of the dwindling number of heroes remaining from NASA’s manned-flight heyday.

Speaking of spaceflight, the closest most of us DIYers can get to space is likely courtesy of a helium-filled balloon. If you’ve ever considered sending something — or someone — aloft, you’ll find this helium balloon calculator an invaluable tool. Just plug in the weight of your payload, select from a few common balloon sizes, and the calculator will tell you how many you need and how much gas it will take to fill them. It’s got a second section that tells you how many more balloons it’ll take to get to a certain altitude, should merely getting off the ground not be enough for you.

If 2020 has proven anything, it’s that time is, at best, a negotiable concept. Improbably, September is only a day away, after an August that somehow took forever to go by in the blink of an eye. With that in mind,  October is OSHWA’s Open Hardware Month, with this year’s theme being “Label and Certify”. We’re a little bit in love with the Open Hardware Facts generator, which takes your open-source hardware, software, and documentation license and generates a USDA “Nutrition Facts”-style label for your product. They’ve also added tools to make it easier to get OSHWA certification for your project.

And finally, what would it be like to pilot a giant exoskeleton? Like, a 9,000 pound (4,100 kg), quadrupedal all-terrain beast of a mech? Turns out you can (theoretically) find out for yourself courtesy of Furrion Exo-Bionics and their monster mech, dubbed Prosthesis. The machine has been in development for a long time, with the vision of turning mech racing into the next big thing in sports entertainment. Their Alpha Mech Pilot Training Program will allow mere mortals to learn how to pilot Prosthesis at the company’s proving ground in British Columbia. Details are sparse, so caveat emptor, but it sure looks like fun.

source https://hackaday.com/2020/08/30/hackaday-links-august-30-2020/

Solar Satellite Glows at Night

They say that imitation is the sincerest form of flattery. If we were going to imitate one of master circuit sculptor Mohite Bhoite’s creations, we’d probably pick the little blinky solar satellite as a jumping off point just like [richardsappia] did. It’s cute, it’s functional, and it involves solar power and supercapacitors. What more could you want?

Sattiny GutsSATtiny is a pummer, which is BEAM robotics speak for a bot that soaks up the sun all day and blinks (or ‘pumms’, we suppose) for as long as it can throughout the night on the juice it collected. This one uses four mini solar panels to charge up a 4 F supercapacitor.

At the controls is an ATtiny25V, which checks every eight seconds to see if the supercapacitor is charging or not as long as there is enough light. Once night has fallen, the two red LEDs will pumm like a pair of chums until the power runs out. Check out the brief demo after the break.

Would you rather have something more nightstand-friendly? Here’s a mini night light sculpture with a friendly glow. If you haven’t started your entry into our Circuit Sculpture Challenge, there’s still plenty of time — the contest runs until November 10th.

source https://hackaday.com/2020/08/30/solar-satellite-glows-at-night/

A PIN Pad Blasting UV Sanitizer

Retailers have instituted enhanced cleaning procedures in response to the COVID-19 pandemic, with an aim to keep frequently touched surfaces as clean as possible. Certainly one of the most commonly handled objects in the entire store is the payment terminal by the register, and the PIN pad specifically. Which is why [Josh Starnes] is working on a UV sterilizer that mounts onto a standard credit card terminal.

Uvpad DetailIt’s a simple enough idea, but as is often the case, figuring out how to properly execute it is where things get tricky. [Josh] has already moved through several design iterations for his 3D printed enclosure in an attempt to make something that’s unobtrusive enough to be practical. The goal is to make something that the user won’t mistake for some kind of skimming device, which can certainly be tricky.

The skeptics in the audience will be happy to hear that [Josh] isn’t bothering with an LED UV source, either. We’ve all seen the pitfalls of trying to sanitize using UV LEDs, so this design goes old school with a small 12 volt UV bulb. That does mean it will need a dedicated power source however, which it seems like he’ll be addressing in the next phase of the project.

 

source https://hackaday.com/2020/08/30/a-pin-pad-blasting-uv-sanitizer/

OCR Reads Old Newspapers So We Don’t Have To

Plenty of people don’t bother to read the current newspaper, let alone editions that were published over 100 years ago. But there’s a wealth of important historical information buried in these dusty old publications, assuming you can find a way to reliably digitize and index it all. You might think the solution is as simple as running images of the paper through optical character recognition (OCR) software, but as [John Scancella] explains, the problem is a bit more complicated than that.

Cvnews Detail
Stretching the text vertically highlights the columns.

Ultimately, the issue largely comes down to formatting. The OCR software reasonably assumes all the text is in orderly horizontal lines, because in the vast majority of cases, it would be. That’s how you’re reading these words now. But as anyone who’s seen an old time newspaper knows, that’s not how things were necessarily written back then. Pages consisted of multiple narrow columns of stories separated by vertical lines; if the OCR tries to read the page from left to right, the resulting text is a mishmash of several unrelated topics.

The answer is to break all those articles into their own images, but doing that manually at any sort of scale simply isn’t an option. So [John] has been working on a system that uses OpenCV to identify the columns of text and isolate them. He details the multi-step process down in his write-up, and even provides the Python code should you want to give it a spin. But the short version is that the image is converted to grayscale and the OpenCV dilate function is used to stretch the text in the Y dimension. This produces big blobs of white that can easily be picked out with findContours() and snipped into individual images.

It’s not a perfect solution, and there are still a few pitfalls. For one, the name of the paper needs to be removed from the front page before the stretching operation happens. But it’s clearly a step in the right direction, and the results certainly look very promising. Anything that makes OCR more accurate or easier to implement is a win in our book, so we’re excited to see where [John] takes this concept.

source https://hackaday.com/2020/08/30/ocr-reads-old-newspapers-so-we-dont-have-to/

OCR Reads Old Newspapers So We Don’t Have To

Plenty of people don’t bother to read the current newspaper, let alone editions that were published over 100 years ago. But there’s a wealth of important historical information buried in these dusty old publications, assuming you can find a way to reliably digitize and index it all. You might think the solution is as simple as running images of the paper through optical character recognition (OCR) software, but as [John Scancella] explains, the problem is a bit more complicated than that.

Cvnews Detail
Stretching the text vertically highlights the columns.

Ultimately, the issue largely comes down to formatting. The OCR software reasonably assumes all the text is in orderly horizontal lines, because in the vast majority of cases, it would be. That’s how you’re reading these words now. But as anyone who’s seen an old time newspaper knows, that’s not how things were necessarily written back then. Pages consisted of multiple narrow columns of stories separated by vertical lines; if the OCR tries to read the page from left to right, the resulting text is a mishmash of several unrelated topics.

The answer is to break all those articles into their own images, but doing that manually at any sort of scale simply isn’t an option. So [John] has been working on a system that uses OpenCV to identify the columns of text and isolate them. He details the multi-step process down in his write-up, and even provides the Python code should you want to give it a spin. But the short version is that the image is converted to grayscale and the OpenCV dilate function is used to stretch the text in the Y dimension. This produces big blobs of white that can easily be picked out with findContours() and snipped into individual images.

It’s not a perfect solution, and there are still a few pitfalls. For one, the name of the paper needs to be removed from the front page before the stretching operation happens. But it’s clearly a step in the right direction, and the results certainly look very promising. Anything that makes OCR more accurate or easier to implement is a win in our book, so we’re excited to see where [John] takes this concept.

source https://hackaday.com/2020/08/30/ocr-reads-old-newspapers-so-we-dont-have-to/

OCR Reads Old Newspapers So We Don’t Have To

Plenty of people don’t bother to read the current newspaper, let alone editions that were published over 100 years ago. But there’s a wealth of important historical information buried in these dusty old publications, assuming you can find a way to reliably digitize and index it all. You might think the solution is as simple as running images of the paper through optical character recognition (OCR) software, but as [John Scancella] explains, the problem is a bit more complicated than that.

Cvnews Detail
Stretching the text vertically highlights the columns.

Ultimately, the issue largely comes down to formatting. The OCR software reasonably assumes all the text is in orderly horizontal lines, because in the vast majority of cases, it would be. That’s how you’re reading these words now. But as anyone who’s seen an old time newspaper knows, that’s not how things were necessarily written back then. Pages consisted of multiple narrow columns of stories separated by vertical lines; if the OCR tries to read the page from left to right, the resulting text is a mishmash of several unrelated topics.

The answer is to break all those articles into their own images, but doing that manually at any sort of scale simply isn’t an option. So [John] has been working on a system that uses OpenCV to identify the columns of text and isolate them. He details the multi-step process down in his write-up, and even provides the Python code should you want to give it a spin. But the short version is that the image is converted to grayscale and the OpenCV dilate function is used to stretch the text in the Y dimension. This produces big blobs of white that can easily be picked out with findContours() and snipped into individual images.

It’s not a perfect solution, and there are still a few pitfalls. For one, the name of the paper needs to be removed from the front page before the stretching operation happens. But it’s clearly a step in the right direction, and the results certainly look very promising. Anything that makes OCR more accurate or easier to implement is a win in our book, so we’re excited to see where [John] takes this concept.

source https://hackaday.com/2020/08/30/ocr-reads-old-newspapers-so-we-dont-have-to/

Olaf Lets an ESP32 Listen to the Music

The joys of overengineering a simple gift. [Joren] wanted to create a dress for his daughter’s fourth birthday that would react with lights in sequence for a song from Frozen. The dress and an LED strip, along with a digital microphone and a battery were easy to procure. But how to make it all work? An ESP32 did the trick.

While the project’s name–Olaf–sounds like it was from Frozen, according to the GitHub page it actually means Overly Lightweight Acoustic Fingerprinting. Right. However, as the name implies, it can learn to identify any sound you want.

One interesting twist. The code is in C, so running it through Emscripten allows the code to run in your browser and you can watch it work alongside a YouTube video of the movie. You can see in the image above that the fingerprint screen gets red dots until it matches the audio and then the dots turn green, indicating a match.

Even if you don’t want a magic Frozen dress, the code on GitHub could be a good starting point for developing audio-sensitive applications.

source https://hackaday.com/2020/08/30/olaf-lets-an-esp32-listen-to-the-music/

Read My Lips, Under this No-Sew Mask

Humans continuously communicate with our bodies, and face masks cover one of the most expressive parts. For some, this is a muffler on strangers, but devastating for people who rely on lip-reading. Several masks exist that have a clear window for precisely this purpose, but they’re specialty and high-demand. [Erin St Blaine] over at Adafruit shows how she makes windowed masks with stuff you may already have in your house. Even if your sewing machine is locked up the local maker-space, you are in luck, because you don’t need a single stitch. For the thread-inclined, it is easy to tweak the recipe.

The part of the mask that touches your face is terry cloth, but any breathable cotton towel should work. There is a PDF in the instructions where you can print templates in four sizes. You will also find a cutout for the plastic window salvaged from your cold soft drink cup. A water bottle should work too. Flexible glue holds the fabric together, but to attach the ear-loops, we fall back on our old friend, the red Swingline. If you don’t have that color and brand, any stapler will do in a pinch. Don’t forget to add some defogger and keep smiling.

Wear your homemade mask proudly and fasten it well, but not too fast.

Thank you, [Gerben], for the tip.

source https://hackaday.com/2020/08/30/read-my-lips-under-this-no-sew-mask/

RC HalfTrack Is Lasercut Masterpiece

The half-track is a vehicle design that has gradually fallen out of favour in the decades since World War II. Combining the benefits of easy driving and handling of wheeled vehicles with the strong mud and snow performance of a tracked vehicle, they served a niche before largely being phased out with the rise of the armoured personnel carrier. [JackCarter] wished to build his own, so whipped up a lasercut RC version of the SdKfz 251 22.

The work is impressive, with [JackCarter] creating the design in Solidworks from photos and illustrations of the vehicle. The moving parts are lasercut, including the tracks themselves, assembled from many tiny lasercut MDF parts. The benefit of using lasercutting to make the model is that it was easy for [Jack Carter] to create simple jigs to ease the process of putting the tracks together. A NodeMCU with a motor shield controls the gear motors used to drive the tracks, and drives a servo for steering. Control is via a smartphone, thanks to the Blynk framework which makes building apps for custom projects easy.

The finished product really shows off [JackCarter]’s 3D design skills, and looks like great fun to build and drive. We’d love to see it with a lick of paint and some period decals to really complete the look. Hackers love a good tracked vehicle, and we’ve seen some impressive builds before. Video after the break.

source https://hackaday.com/2020/08/29/rc-halftrack-is-lasercut-masterpiece/

SDR Transmitting Gets the Power

Most hobby-grade software defined radio setups don’t transmit. Of the few that do, most of them put out anemic levels around one milliwatt or so. If you want to do something outside of the lab, you’ll need an amplifier and that’s what [Tech Minds] shows how to do in a recent video. (Embedded below.)

The video covers LimeSDR, HackRF, and the Pluto SDR, although the amplifiers should work with any transmitter. The SPF5189Z module is quite cheap and covers 50 MHz to 4 GHz, amplifying everything you throw at it. The downside is that it will amplify everything you throw at it, even parts of the signal you don’t want, such as spurs and harmonics.

There are other modules, depending on your needs. The CN0417 covers a very narrow range from 2.4 GHz to 2.5 GHz. (If you can call 100 MHz bandwidth “narrow”.) The RF2126 will cover from 400 Mhz to 2.7 GHz.

None of these are powerhouses. The maximum 20 dB gain will only give you a watt or so out with the minimal drive from most SDR transmitters. But for very many applications, that’s plenty, especially with some filtering.

Unfortunately the gain isn’t stable, and we wonder about the linearity which would affect some modulation modes. There are datasheets for these devices around, such as this one for the SPF5189Z.

If you are really into SDR, the SDR Academy went virtual this year. You might also enjoy this book.

source https://hackaday.com/2020/08/29/sdr-transmitting-gets-the-power/

A Tiny Jacob’s Ladder You Can Build At Home

Big fizzing electrical arcs are fun, and handled properly, not too dangerous either. The Jacob’s Ladder is one such piece of arc-generating equipment, one that featured heavily in vintage sci-fi films. It remains a charming demonstration of high-voltage electrical principles, and you can easily build your own mini version at home.

The build starts with a basic high-voltage step-up kit that turns 4V DC into 15 kV at the output. At this voltage level, it’s possible to generate an arc in air. To create the Jacob’s ladder, the kit is wired up to a pair of closely-spaced electrodes that slowly get farther apart as they go up vertically. When an arc jumps from one electrode to the other, it ionises the air, and the voltage sags due to the current flow. The flowing current heats up the air, which begins to rise, taking the current path with it, causing the familiar climbing arc we all know and love. As the distance between the electrodes increases towards the top, the arc can eventually no longer be sustained. With no current flowing, the voltage rises again, and a new arc forms at the bottom of the device, repeating the process.

It’s a fun build that would make an excellent desk toy, albeit best shown under glass to avoid accidental electric shocks. You can even build a larger one out of microwave parts if you’re so inclined. Video after the break.

source https://hackaday.com/2020/08/29/a-tiny-jacobs-ladder-you-can-build-at-home/

WaterAid Finds Potable Water and Stops Polluters

Millions of people all over the world don’t have access to clean drinking water, and it’s largely because of pollution by corporations and individuals. Solving this problem requires an affordable, scalable way to quickly judge water quality, package the data, and present it to an authority that can crack down on the polluters before the evidence dissipates. Ideally, the solution would be open source and easy to replicate. The more citizen scientists, the better.

[Andrei Florian]’s WaterAid flows directly from this line of thinking. Dip this small handheld device below the surface, and it quickly takes a bunch of water quality and atmospheric readings, averages them, and sends the data to a web dashboard using an Arduino MKR GSM.

WaterAid judges quality by testing the pH and the turbidity of the water, which gauges the amount of impurities. Commercial turbidity sensors work by measuring the amount of light scattered by the solids present in a liquid, so [Andrei] made a DIY version with an LED pointed at a photocell. WaterAid also reads the air temperature and humidity, and reports its location along with a timestamp.

This device can run in one of two modes, depending on the application. The enterprise mode is designed for a fleet of devices placed strategically about a body of water. In this mode, the devices sample continuously, taking readings every 15 minutes, and can send notifications that trigger on predefined thresholds. There’s also a one-and-done individual mode for hikers and campers who need to find potable water. Once WaterAid takes the readings, the NeoPixel ring provides instant color-coded judgment. Check out the demo after the break.

source https://hackaday.com/2020/08/29/wateraid-finds-potable-water-and-stops-polluters/

WaterAid Finds Potable Water and Stops Polluters

Millions of people all over the world don’t have access to clean drinking water, and it’s largely because of pollution by corporations and individuals. Solving this problem requires an affordable, scalable way to quickly judge water quality, package the data, and present it to an authority that can crack down on the polluters before the evidence dissipates. Ideally, the solution would be open source and easy to replicate. The more citizen scientists, the better.

[Andrei Florian]’s WaterAid flows directly from this line of thinking. Dip this small handheld device below the surface, and it quickly takes a bunch of water quality and atmospheric readings, averages them, and sends the data to a web dashboard using an Arduino MKR GSM.

WaterAid judges quality by testing the pH and the turbidity of the water, which gauges the amount of impurities. Commercial turbidity sensors work by measuring the amount of light scattered by the solids present in a liquid, so [Andrei] made a DIY version with an LED pointed at a photocell. WaterAid also reads the air temperature and humidity, and reports its location along with a timestamp.

This device can run in one of two modes, depending on the application. The enterprise mode is designed for a fleet of devices placed strategically about a body of water. In this mode, the devices sample continuously, taking readings every 15 minutes, and can send notifications that trigger on predefined thresholds. There’s also a one-and-done individual mode for hikers and campers who need to find potable water. Once WaterAid takes the readings, the NeoPixel ring provides instant color-coded judgment. Check out the demo after the break.

source https://hackaday.com/2020/08/29/wateraid-finds-potable-water-and-stops-polluters/

Easy-To-Use Music Player Relies on RFID

Microwaves used to be simple to use. Set the dial for the desired time, and hit start. Then, everything went digital and the average microwave now takes between four and six button presses in precise order just to start heating. Music players have gone down a similar path, and those that grew up in the era of vinyl records can find modern digital media simply too hard to work with. To solve this problem, [ananords] whipped up Juuke, a music player focused on ease of use.

The Juuke has a simplistic interface intended to be as easy to use as possible. Songs are selected using printed cards with embedded RFID tags – placing them on the Juuke triggers playback. Volume is controlled with a simple knob, and the only two buttons are for play/pause and shuffle mode.

Underneath, an Arduino Uno runs the show, hooked up to a RC522 RFID interface board. Music is handled by the DFPlayer mini, which loads tracks off a microSD card. The DFPlayer can be hooked up to a speaker directly, but there’s also a 3.5mm jack output if the device is to be used with an external amplifier.

It’s a tidy project, and one that actually looks pretty fun to use. Obviously, there’s some time investment required to prepare the SD card and produce the RFID cards, but the final product could be fun to use at a party, too. We’ve seen similar builds before, as well. Video after the break.

 

source https://hackaday.com/2020/08/29/easy-to-use-music-player-relies-on-rfid/

Two Days Left to Enter the Hackaday Prize!

Your entry for the 2020 Hackaday Prize needs to be in by Monday morning, August 31st!

This is the deadline for initial entries, if you’re one of the one hundred lucky projects that advance to the finals you’ll still have another month to polish up your project. Why not make this weekend your own personal hackathon?

Entries focus on four challenges outlined by our non-profit partners this year. From improving modular dome housing and developing manufacturing techniques in disaster zones, to designing interfaces for people with physical challenges and protecting natural ocean landscapes, there’s plenty of room to be creative here. In addition to the $50,000 grand prize there are still nine other top prizes up for grabs.

You can do this. Tell your story, show a proof of concept, and document it to convince the judges your project is viable. It’ll be tight, but hackers work best when deadlines are looming. We can’t wait to see what you come up with between now and Monday!

source https://hackaday.com/2020/08/29/two-days-left-to-enter-the-hackaday-prize/

Two Days Left to Enter the Hackaday Prize!

Your entry for the 2020 Hackaday Prize needs to be in by Monday morning, August 31st!

This is the deadline for initial entries, if you’re one of the one hundred lucky projects that advance to the finals you’ll still have another month to polish up your project. Why not make this weekend your own personal hackathon?

Entries focus on four challenges outlined by our non-profit partners this year. From improving modular dome housing and developing manufacturing techniques in disaster zones, to designing interfaces for people with physical challenges and protecting natural ocean landscapes, there’s plenty of room to be creative here. In addition to the $50,000 grand prize there are still nine other top prizes up for grabs.

You can do this. Tell your story, show a proof of concept, and document it to convince the judges your project is viable. It’ll be tight, but hackers work best when deadlines are looming. We can’t wait to see what you come up with between now and Monday!

source https://hackaday.com/2020/08/29/two-days-left-to-enter-the-hackaday-prize/

Automation With a New Twist

Turning on a lightbulb has never been easier. You can do it from your mobile. Voice activation through home assistants is robust. Wall switches even play nicely with the above methods. It was only a matter of time before someone decided to make it fun, if you consider a Rubik’s cube enjoyable. [Alastair Aitchison] at Playful Technology demonstrated that it is possible to trigger a relay when you match all the colors. Video also after the break.

The cube does little to obfuscate game data, so in this scope, it sends unencrypted transmissions. An ESP32 with [Alastair]’s Arduino code, can track each movement, and recognize a solved state. In the video, he solves the puzzle, and an actuator releases a balloon. He talks about some other cool things this could do, like home automation or a puzzle room, which is in his wheelhouse judging by the rest of his YouTube channel.

We would love to see different actions perform remote tasks. Twisting the top could set a timer for 1-2-3-4-5 minutes, while the bottom would change the bedroom lights from red-orange-yellow-green-blue-violet. Solving the puzzle should result in a barrage of NERF darts or maybe keep housemates from cranking the A/C on a whim.

source https://hackaday.com/2020/08/29/automation-with-a-new-twist/