Tesla Turbine Boat Uses Lily Impeller

September 26, 2020 by Zoe Skyforest 19 Comments

Typically in the RC community, radio control boats rely on small nitro engines or electric motors to get around. Fitted with traditional propellers, they’re capable of great speed and performance. Of course, there’s more than one way to skin a cat, as [Integza] shows with his latest build.

As far as the boat side of things is concerned, it’s a basic 3D printed single hull design. The innovation comes in the drivetrain, instead. The boat uses compressed air for propulsion, stored in a battery of four soda bottles, pressurized to 6 bar. The compressed air is used to drive a Tesla turbine of [Integza]’s design, which is 3D printed on a resin printer. Rather then driving a propeller, the Tesla turbine instead turns a Lily impeller, which pulls the boat through the water rather than pushing it along. The impeller uses a nature-inspired design, hence the name, and was also 3D printed, making producing its complex geometry a cinch. The guts of a toy radio control car are then used to control the boat.

Understandably, performance is less than stellar. The limited reserves of compressed air can’t propel the boat long, and the combination of the high RPM Tesla turbine and Lily impeller don’t provide a lot of thrust. However, the boat does move under its own power, demonstrating these oddball technologies while doing so.

[Integza] has been working with these technologies for a while; we featured an earlier Tesla turbine build back in 2018. Video after the break.

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Fermenting Yogurt With The Help Of Hardware

September 26, 2020 by Zoe Skyforest 15 Comments

Fermentation is a natural process that has been exploited by humanity for millennia. Behind such favorites as cheese and beer, it takes just the right conditions to get the desired results. To aid in this process, and to explore the crafts of their ancestors, [Victoria] and [Petar] created an electronic fermentation quilt.

Bulgarian yogurt was the tasty end result from this work.

Anyone familiar with breadmaking will be familiar with throwing a cloth over dough when left to rest. This is all about temperature management, providing optimum conditions for the yeast to work their magic. This fermentation quilt takes things to the next level, integrating soft heater pads and temperature sensing hardware into the fabric itself. Rather than acting as a simple insulator, the quilt can actively supply heat where needed, switching off when reaching the set temperature. In this example, the quilt is set to maintain a temperature of 45 degrees for the optimum production of Bulgarian yogurt.

The fermentation quilt serves as an excellent example of what can be achieved when combining textiles with smart electronics. Tools like Adafruit’s Lilypad and conductive thread all come together to make this a functional and useful device, and shows that electronic textiles aren’t just limited to blinky wearables.

Fermentation is a popular topic among hackers, with [Trent Fehl]’s Supercon talk at the 2019 Supercon covering similar ground from a sourdough perspective. It goes to show that hardware skills can pay off in the kitchen, too!

Building A Compact Reflow Oven With Halogen Lamps

September 25, 2020 by Zoe Skyforest 7 Comments

Very often, particularly on the Internet, we’re fooled into thinking bigger is always better. The fact remains that this isn’t always the case. When it comes to reflow ovens, for example if you’re working with short runs of small PCBs, or if you just don’t have a lot of space in the workshop, a smaller oven will be more desirable than a large one. It’s factors like these that drove [Sergi Martínez]’s latest build.

Built inside a metal project case, first attempts involved using an off-the-shelf heating element, with poor results. The element had a high thermal inertia, and was designed for use in water, so didn’t last in the reflow application. Learning from the experience of others, [Sergi] switched to using halogen lamps, netting much greater success. An Arduino Nano is responsible for running the show, using firmware developed by [0xPIT]. There’s also a screen for monitoring reflow profiles, and a cooling fan to help keep temperature in the ideal zone.

It’s a tidy build that would be particularly useful for quickly running batches of small PCBs without the long wait times required to heat a larger oven. Energy efficiency should be better, too. Of course, if you’re a fan of the classic toaster oven builds, we’ve got those too. Video after the break.

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DIY Grout Cleaning Machine Does A Good Job

September 24, 2020 by Zoe Skyforest 26 Comments

Cleaning tiled floors can be a drag. Getting the tiles themselves clean is bad enough, but often dealing with the grouted joints in between requires more elbow grease and attention to detail. It’s a tedious chore, and thus one ripe for improvement. [Elite Worm]’s cleaning machine is an excellent solution to the problem.

The machine is built entirely from scratch, using primarily 3D printed components. A fluid tank is fitted to the chassis, along with a custom 3D-printed pump run by a DC motor, to deliver cleaning product where its needed. A large DC motor is then used to spin a nylon brush which gets deep in the tile grooves to clean out the grime. The chassis is then fitted with rollers to allow it to glide along the floor. Finally, a handle is fitted which allows the user to push the tool along, with switches to turn on the spinning brush and dispense cleaning fluid.

It’s a great tool, and one which eliminates hours of scrubbing on hands and knees. We’re sure the time investment in the build will pay off before long. We’ve seen other tricky cleaning hacks before, too. Video after the break.

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Community Testing Suggests Bias In Twitter’s Cropping Algorithm

September 23, 2020 by Zoe Skyforest 77 Comments

With social media and online services are now huge parts of daily life to the point that our entire world is being shaped by algorithms. Arcane in their workings, they are responsible for the content we see and the adverts we’re shown. Just as importantly, they decide what is hidden from view as well.

Important: Much of this post discusses the performance of a live website algorithm. Some of the links in this post may not perform as reported if viewed at a later date.

The initial Zoom problem that brought Twitter’s issues to light.

Recently, [Colin Madland] posted some screenshots of a Zoom meeting to Twitter, pointing out how Zoom’s background detection algorithm had improperly erased the head of a colleague with darker skin. In doing so, [Colin] noticed a strange effect — although the screenshot he submitted shows both of their faces, Twitter would always crop the image to show just his light-skinned face, no matter the image orientation. The Twitter community raced to explore the problem, and the fallout was swift.

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How To Create Hermetically Sealed Electrical Connections

September 23, 2020 by Zoe Skyforest 25 Comments

[Eric Strebel] is no stranger to pressure and vaccum tanks, regularly using them for all manner of resin casting jobs for his product design business. However, sometimes it becomes necessary to run equipment within a pressure tank, such as for rotomoulding or other similar jobs. In order to get power into a tank under pressure, [Eric] built a special plug with a hermetic seal to do the job. (Video, embedded below.)

The build starts with a large metal plug which screws into the pressure vessel, into which a square recess is machined. For the electrical passthrough, [Eric] selected GX-16 aviation connectors, in this case packing six conductors. The connectors are hooked up back-to-back through the hole in the metal tank plug, using bare copper wire. This is to avoid insulation on wires acting as a channel for gases to pass through. With the connectors wired up and an acrylic disc in place to stop overflow, the metal plug is filled with resin to create the hermetic seal.

Results are good, with the connectors functioning electrically and the resin acting as a perfect seal. There’s a small risk of short circuit with the exposed copper conductors, but [Eric] is exploring some easy solutions to avoid issues. We’ve seen his work before, too – like this great discussion on cardboard as a design tool. Video after the break.

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A Digital Guestbook Is A Perfect Hacker Wedding Gift

September 22, 2020 by Zoe Skyforest 2 Comments

With his brother’s wedding coming up, [Sebastian] needed a wedding gift. Rather than purchasing something, he elected to build a digital guestbook so guests could share their well-wishes with the happy couple.

The guestbook has a simple web-based interface, which was accessible over a domain name [Sebastian] registered with the couple’s names ahead of the event. There, users could enter text and draw a friendly message for the digital guestbook. The guestbook itself consists of an ESP32 running a e-ink display, packaged in a tidy 3D printed enclosure featuring the couple’s initials. It regularly queries the web server, and displays the messages it finds on the screen.

It’s a great use of an e-ink display, as it made reading the messages in bright daylight easy where other technologies may have faltered. [Sebastian] was also clever to install some LEDs for the night portion of the reception. We’ve featured a few wedding gifts on these pages before, including this particularly amusing sugar cube. Video after the break.

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