Self Driving Cars Learn From Our Eyes

[Michelle Hampson] reports in IEEE Spectrum that Chinese researchers may improve self-driving cars by mimicking how the human eye works. In some autonomous cars, two cameras use polarizing filters to help understand details about what the car sees. However, these filters can penalize the car’s vision in low light conditions.

Humans, however, have excellent vision in low-lighting conditions. The Retinex theory (based on the Land Effect discovered by [Edwin Land]) attributes this to the fact that our eyes sense both the reflectance and the illumination of light. The new approach processes polarized light from the car’s cameras in the same way.

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A photo of a white dog with curly fur riding a black skateboard with grey motors under the front deck. There are blue squares on the top of the deck that she is standing on to steer the board.

An Electric Skateboard For The Dogs

What’s a dog to do if they want to do some accessible skateboarding? [Simone Giertz]’s three-legged pup, [Scraps], got the chance to try a LEGO Technic board for her thrills.

This electric LEGO skateboard features six motors and paw pedals to let [Scraps] steer while [Giertz] remotely controls the speed of the board. While it’s not a particularly fast ride, it does let [Scraps] live out her dreams of being a YouTube dog skateboard celebrity.

A video from [Giertz] wouldn’t be complete without a life lesson, and this time it was the importance of rest to the creative process. Sometimes when a solution eludes you, it’s just time to take a break. The steering mechanism, in particular, was giving her trouble but became simple the next morning. We’re also treated to an adorable shot of [Scraps] napping when the initial shoot of her riding the board wasn’t going as planned.

Want to try your hand at making your own skateboard? How about a deck from recycled plastic, tank treads instead of wheels, or is a rocket-powered skateboard more your speed?

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A tricked-out kids' Jeep in black and silver.

Driven To Over-Engineer A Kids’ Car

You know, it feels as though it’s getting more and more difficult to compete for Father of the Year around here. And [Jon Petter Skagmo] just laid down a new gauntlet — the incredibly overly-engineered kids car.

Close-up of the dash panel of an overly-engineered kids' car.While the original plan was to build the entire car from scratch, [Jon] eventually opted to use an off-the-shelf car that had a dead battery.

While the original architecture was quite simple, the new hardware has just about everything a kid could want in a tricked-out ride, most of which is accessible through the really cool dashboard.

We’re talking headlights, a music player, a siren, a selfie video cam that doubles as two-way communication with the driver, and even a garage door opener that uses an MQTT connection.

Under the cute little hood is where you’ll find most of the electronics. The car’s brain is a Raspberry Pi 3B, and there’s a custom daughter board that includes GPS/GNSS. This was originally meant to geofence [Baby Girl Skagmo] in, but Dad quickly realized that kids are gonna kid and disabled it pretty soon after.

This isn’t the first high-tech rebuild of a kiddie car that we’ve seen here at Hackaday. Makes us wish we were quite a bit smaller…

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Building A Small Gyro Stabilized Monorail

Monorails aren’t just the core reason why The Simpsons remains on air after thirty-six seasons, twenty-six of which are unredeemable garbage. They’re also an interesting example of oddball rail travel which has never really caught on beyond the odd gadgetbahn project here and there. [Hyperspace Pirate] recently decided to investigate the most interesting kind of monorail of all—the gyro stabilized type—on a small scale for our viewing pleasure.

The idea of a gyro-stabilized monorail is to use active stability systems to allow a train to balance on a single very thin rail. The benefits of this are questionable; one ends up with an incredibly expensive and complex rail vehicle that must always run perfectly or else it will tip over. However, it is charming to watch in action.

[Hyperspace Pirate] explains how the monorail vehicle uses control moment gyroscopes to keep itself upright. The video also explains the more common concept of reaction wheels so the two systems can be contrasted and compared. It all culminates in a wonderful practical demonstration with a small 3D printed version of a 20th-century gyro monorail running on a 24″ track.

If you’re studying mechanical engineering this is a great project to pore over to see theoretical principles put into obvious practice. Video after the break.

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Tech In Plain Sight: Speedometers

In a modern car, your speedometer might look analog, but it is almost certainly digital and driven by the computer that has to monitor all sorts of things anyway. But how did they work before your car was a rolling computer complex? The electronic speedometer has been around for well over a century and, when you think about it, qualifies as a technlogical marvel.

If you already know how they work, this isn’t a fair question. But if you don’t, think about this. Your dashboard has a cable running into it. The inner part of the cable spins at some rate, which is related to either the car’s transmission or a wheel sensor. How do you make a needle deflect based on the speed?

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Open Source Liquid Rocket Reaches For The Sky

Since the very beginning, solid-propellants have been the cornerstone of amateur rocketry. From the little Estes rocket picked up from the toy store, to vehicles like the University of Southern California’s Traveler IV that (probably) crossed the Kármán line in 2019, a rapidly burning chunk of solid propellant is responsible for pushing them skyward. That’s not to say that amateur rockets powered by liquid propellants are completely unheard of … it’s just that getting them right is so ridiculously difficult that comparatively few have been built.

But thanks to [Half Cat Rocketry], we may start to see more hobbyists and students taking on the challenge. Their Mojave Sphinx liquid-fueled rocket is not only designed to be as easy and cheap to build as possible, but it’s been released as open source so that others can replicate it. All of the 2D and 3D CAD files have been made available under the GPLv3 license, and if you’re in the mood for a little light reading, there’s a nearly 370 page guidebook you can download that covers building and launching the rocket.

Now of course we’re still talking about literal rocket science here, so while we don’t doubt a sufficiently motivated individual could put one of these together on their own, you’ll probably want to gather up a couple friends and have a well-stocked makerspace to operate out of. All told, [Half Cat] estimates you should be able to build a Mojave Sphinx for less than $2,000 USD, but that assumes everything is done in-house and you don’t contract out any of the machining.

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For years, the first Air Force One sat neglected and forgotten in an open field at Arizona’s Marana Regional Airport. (Credit: Dynamic Aviation)

The First Air Force One And How It Was Nearly Lost Forever

Although the designation ‘Air Force One’ is now commonly known to refer to the airplane used by the President of the United States, it wasn’t until Eisenhower that the US President would make significant use of a dedicated airplane. He would have a Lockheed VC-121A kitted out to act as his office as commander-in-chief. Called the Columbine II after the Colorado columbine flower, it served a crucial role during the Korean War and would result the coining of the ‘Air Force One’ designation following a near-disaster in 1954.

This involved a mix-up between Eastern Air Lines 8610 and Air Force 8610 (the VC-121A). After the Columbine II was replaced with a VC-121E model (Columbine III), the Columbine II was mistakenly sold to a private owner, and got pretty close to being scrapped.

In 2016, the plane made a “somewhat scary and extremely precarious” 2,000-plus-mile journey to Bridgewater, Virginia, to undergo a complete restoration. (Credit: Dynamic Aviation)
In 2016, the plane made a “somewhat scary and extremely precarious” 2,000-plus-mile journey to Bridgewater, Virginia, to undergo a complete restoration. (Credit: Dynamic Aviation)

Although nobody is really sure how this mistake happened, it resulted in the private owner stripping the airplane for parts to keep other Lockheed C-121s and compatible airplanes flying. Shortly before scrapping the airplane, he received a call from the Smithsonian Institution, informing him that this particular airplane was Eisenhower’s first presidential airplane and the first ever Air Force One. This led to him instead fixing up the airplane and trying to sell it off. Ultimately the CEO of the airplane maintenance company Dynamic Aviation, [Karl D. Stoltzfus] bought the partially restored airplane after it had spent another few years baking in the unrelenting sun.

Although in a sorry state at this point, [Stoltzfus] put a team led by mechanic [Brian Miklos] to work who got the airplane in a flying condition by 2016 after a year of work, so that they could fly the airplane over to Dynamic Aviation facilities for a complete restoration. At this point the ‘nuts and bolts’ restoration is mostly complete after a lot of improvisation and manufacturing of parts for the 80 year old airplane, with restoration of the Eisenhower-era interior and exterior now in progress. This should take another few years and another $12 million or so, but would result in a fully restored and flight-worthy Columbine II, exactly as it would have looked in 1953, plus a few modern-day safety upgrades.

Although [Stoltzfus] recently passed away unexpectedly before being able to see the final result, his legacy will live on in the restored airplane, which will after so many years be able to meet up again with the Columbine III, which is on display at the National Museum of the USAF.