Ground Effect Aerodynamics On An RC Car

December 21, 2021 by 3 Comments

Ground effect aerodynamics will return to Formula 1 in a big way in the 2022 season, hopefully washing away the bad taste left in fan’s mouths after the recent controversial season decider. [Engineering After Hours] has experimented with F1 aerodynamics on RC cars before, and decided that it was time to try and implement a proper ground-effect design himself.

The aim of ground effect aerodynamics is to create a constriction for airflow between the bottom of the car and the ground underneath. This constriction accelerates the flow beneath the car, and as per Bernoulli’s principle, causes a corresponding pressure drop, sucking the car down onto the track. Viscosity also plays a role; from the car’s perspective, the road beneath the vehicle is moving backwards at some speed, pulling on the fluid thanks to the boundary layer on the ground itself. This further helps increase the strength of the effect.

A vacuum-formed undertray complete with side skirts was installed on the RC car in order to generate ground effect downforce. A quick test with a leaf blower indicates the system works, and that the side skirts are a key component.

Lateral acceleration was significantly improved by around 20% in testing with the ground effects installed, though [Engineering After Hours] admits that without a wind tunnel, the results aren’t the most scientific. However, with the undertray being relatively lightweight, we suspect the aero elements are likely providing plenty of benefit without too much of a negative effect on acceleration or handling.

Check out some of the other aero experiments [Engineering After Hours] has undertaken, too. Video after the break. Continue reading “Ground Effect Aerodynamics On An RC Car” →

Box with a hole. Camera and Raspberry Pi inside.

A Label Maker That Uses AI Really Poorly

December 21, 2021 by 15 Comments

[8BitsAndAByte] found herself obsessively labeling items around her house, and, like the rest of the world, wanted to see what simple, routine tasks could be made unnecessarily complicated by using AI. Instead of manually identifying objects using human intelligence, she thought it would be fun to offload that task to our AI overlords and the results are pretty amusing.

She constructed a cardboard enclosure that housed a Raspberry Pi 3B+, a Pi Camera Module V2, and a small thermal printer for making the labels. The enclosure included a hole for the camera and a button for taking the picture. The image taken by the Pi is analyzed by the DeepAI DenseCap API which, in theory, should create a label for each object detected within the image. Unfortunately, it doesn’t seem to do that very well and [8BitsAndAByte] is left with labels that don’t match any of the objects she took pictures of. In some cases it didn’t even get close, for example, the model thought an apple was a person’s head and a rotary dial phone was a cup. Go figure. It didn’t really seem to bother her though, and she got a pretty good laugh from the whole thing.

It appears the model detects all objects in the image, but only prints the label for the object it was most certain about. So maybe part of her problem is there were just too many objects in the background? If that were the case, you could probably improve the accuracy of the model by placing the object against a neutral background. That may confuse the AI a lot less and possibly give you better results. Or maybe try a different classifier altogether? Or don’t. Then you could just use it as a fun, gag project at your next get-together. That works too.

Cool project [8BitsAndAByte]! Hey, maybe this is a sign the world will still need some human intelligence after all. Who knows?

Continue reading “A Label Maker That Uses AI Really Poorly” →

Hydrogen Generation Made Easy

December 20, 2021 by 45 Comments

Even if you never want to generate hydrogen, [Maciej Nowak’s] video (embedded below) is interesting to watch because of the clever way the electrode is formed from stainless steel washers. You’ll need heat shrink tubing, but you ought to have that hanging around anyway. Building the electrode using the techniques in the video results in a lot of surface area which is important for an electrochemical reaction.

A standard rechargeable cell provides power for the generator which resides in a modified plastic bottle. The overall build looks good even though it is all repurposed material.

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The Assassin’s Teapot Is A Mischievous Design

December 20, 2021 by 31 Comments

Many films use a similar trope when it comes to poisoning. The aspiring murderer ingests a drink poured from the same vessel as that given to their intended victim to indicate the liquid is safe to imbibe. The Assassin’s Teapot is a way one could achieve such a ruse, allowing two different liquids to be poured from what is seemingly a regular teapot, as shown by [Steve Mould]. (Video after the break.)

The trick is simple. Two separate cavities exist within the teapot, exiting via their own paths in the same spout. Each cavity also has an air hole in the top. If the hole for a given cavity is blocked by the pourer’s thumb, the liquid will not flow.

Each cavity can be filled with its own liquid. For example, one can be filled with tea, the other with poisoned tea. The murderer blocks the hole for the poison cavity when pouring their own beverage, delivering tea to their own glass. Then, when pouring for the enemy, the hole for the tea cavity is blocked, and poison is allowed to flow into the glass of one’s target.

The workings are simple; if air cannot flow into the cavity of the teapot to replace liquid flowing out, air pressure will stop the liquid flowing at all. The concept is demonstrated ably by [Steve]’s 2D recreation, letting us visualize the workings of the teapot quite easily.

It also shows a minor flaw in the design, which should be accounted for –  if the spout isn’t designed carefully, sometimes flow from one cavity can dribble into the other. Between this and the chance of getting confused about which hole to cover to pour the poison, it would pay to keep some antidote on hand. Or, alternatively, just pour your guests tea instead – they’ll appreciate it!

We’ve seen [Steve] explore similarly interesting liquid vessels before too, such as this simple breakdown of the workings of the Gluggle Jug.

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Concrete With 3D Printed Foam Forms

December 20, 2021 by 17 Comments

The latest 3D printing application?  Forming concrete. That’s according to a team at ETH Zurich who claims that construction with foam forms cuts concrete usage up to 70%. It also offers improved insulation properties. You can see a video about the process, below.

Typical concrete work relies on a form often made with wood, steel, or plastic. That’s easy to do, but hard to make complex shapes. However, if you can create complex shapes you can easily put material where it adds strength and omit material where it doesn’t carry load. Using a robotic-arm 3D print technique, the researchers can lay out prefabricated blocks of foam that create forms with highly complex shapes. Continue reading “Concrete With 3D Printed Foam Forms” →

All Hail Your New Giant 555 Timer Overlord

December 20, 2021 by 46 Comments

You asked for it, and now you’ve got it. It’s taken more than a decade of accumulated complaining, but this gigantic 555 timer IC has finally gathered enough psychokinetic energy to take corporeal form and demand fealty from the readers of Hackaday.

Or not. The less exciting explanation is that creator [Rudraksha Vegad] was looking for a way to combine his interests in discrete electronic components and woodworking. The result is an incredible build that’s more than just a conversation starter; this desktop-sized version of the iconic integrated timer circuit is fully functional. You can even hook it up to a breadboard, assuming you’ve got some alligator clips handy.

Lifting the lid on this wooden “chip” uncovers an intricate hand-wired array of discrete components that stand in for the microscopic goings on inside the real thing. He’s even gone through the trouble of recreating the symbols for the comparators and flip-flops that you’d see in a diagram of a 555 using wooden shapes to elevate their respective components. It might not fit the classical definition, but surely this must count as some form of circuit sculpture.

[Rudraksha] credits several other projects for not just inspiring him to create his own mega 555, but for helping him wrap his head around the internal workings of everyone’s favorite IC. Using components he salvaged from old hardware, he says the project ended up being very educational for him. These days, when most makers are more likely to reach for a microcontroller than a logic chip, spending some quality time with transistors and passives can be quite illuminating.

Continue reading “All Hail Your New Giant 555 Timer Overlord” →

A world map with a small magetic plane sitting on Japan

“Window To The World” Brings Far-Off Places To Your Home

December 20, 2021 by 13 Comments

For those who love travelling around the world, life hasn’t been great for the past two years. World-wide lockdowns and travel restrictions have kept many people stuck inside their own homes when they would rather be jetting off to distant cities. If you’re one of those bothered by Wanderlust, [Alex Shakespeare] might have a solution for you: a window that shows a live image from another location around the world.

A window showing a live webcam feed
The Window, showing a live feed from Tokyo.

To make the experience as lifelike as possible, [Alex] used an actual window in his London home and mounted a large TV behind it. A wall-mounted map enables him to choose any of five locations by moving a little magnetic plane across the map. LEDs show the available spots, while magnetometers detect the motion of the aircraft. An ESP8266 then instructs a media server to connect to the appropriate livestream, which is subsequently displayed on the TV screen.

All of this is clever enough already, but [Alex] decided to go one step further and added a thermal sensor that detects the location of any persons standing near the display and shifts the image a little when they move. This simulates the perspective of looking out a real window, and should give the image a more life-like quality than if it were simply static.

The whole design is available on [Alex]’s GitHub page, ready to be replicated by anyone who wants to look out over some exotic location. If, instead, you want a way to reminisce about the places you’ve visited in the past, check out this cool souvenir globe. We’ve also seen a neat Google Maps based one a few years back.

Continue reading ““Window To The World” Brings Far-Off Places To Your Home” →