Charging An Electric Supercar With Lemons, Kids, And The Sun

June 29, 2018 by Dan Maloney 27 Comments

First things first: the tease on this video, that an electric supercar can be charged from a massive lemon battery array, is exactly that – a tease. Despite that, it makes for an interesting story and a great attempt to get kids exposed to science and engineering.

The story goes that [Mark] was approached by Volkswagen to help charge the batteries on their entry for the upcoming Pikes Peak International Hill Climb, the annual “Race to the Clouds” in Colorado. Racers are tortured by a 4,700′ (1,440 m) vertical climb over a 12.42 mile (20 km) course that features 156 switchback turns. Volkswagen’s entry is an electric supercar, and they sent [Mark] a portable battery cart to charge up the best way he saw fit.

Teaming up with [William Osman], the first attempt was a massive array of lemon cells, made with waterjet-cut strips of zinc and copper held in a plywood frame. Studded with 1,232 lemons, the battery performed just about as well as you’d expect it would. Plan B was cute, and another of [Mark]’s attempts to pad his “Funnest Uncle Ever” score a bit. He devised a zip line with regenerative braking to charge a cordless drill battery, and then indirectly harvested the energy in the battery by turning it into lemonade for a bunch of kids. The sugared-up kids rode the zip line till the battery was charged.

That was still a drop in the bucket, though, so Plan C saw [Mark] install a large solar array on his roof; the tie-in here was that the lemon-powered kids got to design a cleaning system for the solar array. A weak link, to be sure, but the kids had fun, and we can’t deny that the car will at least be partially lemon-powered when it heads up the hill.

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When The Going Gets Tough, These Wheels Transform To Tracks

June 29, 2018 by Roger Cheng 29 Comments

When we want to build something to go where wheels could not, the typical solution is to use tracks. But the greater mobility comes with trade-offs: one example being tracked vehicles can’t go as fast as a wheeled counterpart. Information released by DARPA’s ground experimental vehicle technology (GXV-T) program showed what might come out of asking “why can’t we switch to tracks just when we need them?”

This ambitious goal to literally reinvent the wheel was tackled by Carnegie Mellon’s National Robotics Engineering Center. They delivered the “Reconfigurable Wheel-Track” (RWT) that can either roll like a wheel or travel on its tracks. A HMMWV serves as an appropriate demonstration chassis, where two or all four of its wheels were replaced by RWTs. In the video (embedded below) it is seen quickly transforming from one mode to another while moving. An obviously desirable feature that looks challenging to implement. This might not be as dramatic of a transformation as a walking robot that can roll up into a wheel but it has the advantage of being more immediately feasible for human-scale vehicles.

The RWT is not the only terrain mobility project in this DARPA announcement but this specific idea is one we would love to see scaled downed to become a 3D-printable robot module. And though our Hackaday Prize Robotics Module Challenge has already concluded, there are more challenges still to come. The other umbrella of GXV-T is “crew augmentation” giving operators better idea of what’s going around them. The projects there might inspire something you can submit to our upcoming Human-Computer Interface Challenge, check them out!

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Building A Mini Electric Bike In Between Projects

June 26, 2018 by Steven Dufresne 13 Comments

What do you do when you suddenly find you have some free time because you’re waiting on parts or have run up against other delays for your current project? If you’re [James Bruton], you design and build a mini electric bike.

Being a prolific builder, [James] already had the parts he needed. Some of them were left over from previous projects: a small motor, a 24 volt LiPo battery, an SK8 electronic speed controller, and a twist grip for the handlebars. He cut a wooden frame using his CNC machine and 3D printed various other components. Normally he uses ABS for motor mounts but this time he went with PLA and sure enough, the motor heated up and the mounting screws got hot enough to melt the plastic. But other than that, the bike worked great and looks like a polished, manufactured product. How many of us can say the same for our own unplanned projects using only parts from around the workshop? Check out his build and watch him whizzing around on it in the video below.

As for the former projects from which he had leftover parts, he says that some came from skateboard projects such as his pimped out electric LEGO longboard.

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The Electric Vehicles Of EMF Camp

June 25, 2018 by Jenny List 3 Comments

There is joy in the hearts of British and European hardware and software hackers and makers, for this is an EMF Camp year. Every couple of years, our community comes together for three summer days in a field somewhere, and thanks to a huge amount of work from its organizers and a ton of volunteers, enjoys an entertaining, stimulating, and engrossing hacker camp.

One of the features of a really good hacker camp are the electric vehicles. Not full-on electric cars, but personal camp transport. Because only the technically inept walk, right? From Hitchin’s Big Hak to TOG’s duck, with an assortment of motorized armchairs and beer crates thrown in, these allow the full creativity of the hardware community free rein through the medium of overdriven motors and cheap Chinese motor controllers.

This year at EMF Camp there will be an added dimension that should bring out a new wave of vehicles, there will be a Hacky Racers event. Novelty electric vehicles will compete for on-track glory, will parade around the camp, and will no doubt also sometimes release magic smoke. There is still plenty of time to enter, so if you’re going to EMF, get building!

We have an interest in these little electric vehicles, not least because there may well be a Hackaday-branded machine on the tarmac. We’d like to feature some of them over the weeks running up to the event, so if you are building one and have a write-up handy, please tell us about it in the comments. Charge your batteries, and we’ll see you there!

Header image: [Mark Mellors], with permission.

An Arduino Powered Tank Built To Pull Planes

June 19, 2018 by Tom Nardi 39 Comments

Surely our readers are well aware of all the downsides of owning an airplane. Certainly the cost of fuel is a big one. Birds are a problem, probably. That bill from the traveling propeller sharpener is a killer too…right? Alright fine, we admit it, nobody here at Hackaday owns an airplane. But probably neither do most of you; so don’t look so smug, pal.

But if you did own a plane, or at least work at a small airport, you’d know that moving the things around on the ground is kind of a hassle. Smaller planes can be pulled by hand, but once they get up to a certain size you’ll want some kind of vehicle to help out. [Anthony DiPilato] wanted a way to move around a roughly 5,200 pound Cessna 310, and decided that all the commercial options were too expensive. So he built his own Arduino powered tank to muscle the airplane around the tarmac (if site is down try Google cache), and his journey from idea to finished product is absolutely fascinating to see.

So the idea here is pretty simple. A little metal cart equipped with two beefy motors, an Arduino Mega, a pair of motor controllers, and a HC-08 Bluetooth module so you can control it from your phone. How hard could it be, right? Well, it turns out combining all those raw components into a little machine that’s strong enough to tow a full-scale aircraft takes some trial and error.

It took [Anthony] five iterations before he fine tuned the design to the point it was able to successfully drag the Cessna without crippling under the pressure. The early versions featured wheels, but eventually it was decided that a tracked vehicle would be required to get enough grip on the blacktop. Luckily for us, each failed design is shown along with a brief explanation about what went wrong. Admittedly it’s unlikely any of us will be recreating this particular project, but we always love to see when somebody goes through the trouble of explaining what went wrong. When you include that kind of information, somewhere, somehow, you’re saving another maker a bit of time and aggravation.

Hackers absolutely love machines with tank treads. From massive 3D printed designs to vaguely disturbing humanoid robots, there’s perhaps no sweeter form of locomotion in the hacker arsenal.

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Social Engineering By Railways

June 7, 2018 by Brian McEvoy 29 Comments

Where do you travel every day? Are there any subtle ploys to manipulate your behavior? Would you recognize them or are they just part of the location? Social engineering sometimes gets a bad rap (or is it rep?) in the mainstream, but the public-facing edge of that sword can keep order as it does in Japanese train stations. They employ a whirlwind of psychological methods to make the stations run like clockwork.

The scope of strategies ranges from the diabolical placement of speakers emitting high-frequency tones to discourage youthful loitering to the considerate installation of blue lights to deter suicides. Not every tactic is as enlightened as suicide prevention, sometimes, just changing the grating departure buzzer to a unique tune for each station goes a long way to relieving anxiety. Who wants to stand next to an anxious traveler who is just getting more and more sweaty? Listen below the break to hear what Tokyo subway tunes sound like.

Maybe you can spot some of these tricks where you live or something similar can ease your own commute. Perhaps the nearest subway has a piano for stairs or a 3D printing cyborg.

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Tesla Model 3 Battery Pack Teardown

June 4, 2018 by Tom Nardi 53 Comments

The Tesla Model 3 has been available for almost a year now, and hackers and tinkerers all over the world are eager to dig into Elon’s latest ride to see what makes it tick. But while it’s considerably cheaper than the Model S that came before it, the $35,000+ USD price tag on the new Tesla is still a bit too high to buy one just to take it apart. So for budget conscious grease monkeys, the only thing to do is wait until somebody with more money than you crashes one and then buy the wreckage cheaply.

Which is exactly what electric vehicle connoisseur [Jack Rickard] did. He bought the first wrecked Model 3 he could get his hands on, and proceeded to do a lengthy teardown on what’s arguably the heart and soul of the machine: its 75 kWh battery pack. Along the way he made some interesting discoveries, and gained some insight on to how Tesla has been able to drop the cost of the Model 3 so low compared to their previous vehicles.

On a Tesla, the battery pack is a large flat panel which takes up effectively the entire underside of the vehicle. To remove it, [Jack] and his assistant raise the wreck of the Model 3 up on a standard lift and then drop the battery down with a small lift table. Here the first differences are observed: while the Model S battery was made for rapid swapping (a feature apparently rarely utilized in practice), the battery in the Model 3 battery is obviously intended to be a permanent piece of the car; removing it required taking out a good portion of the interior.

With the battery out of the car and opened up, the biggest change for the Model 3 becomes apparent. The battery pack actually contains the charger, DC-DC converter, and battery management system in one integrated unit. Whereas on the Model S these components were installed in the vehicle itself, on the Model 3, most of the primary electronics are stored in this single module.

That greatly reduces the wiring and complexity of the car, and [Jack] mentions the only significant hardware left inside the Model 3 (beyond the motors) would be the user interface computer in the dashboard. When the communication protocol for this electronics module is reverse engineered, it may end up being exceptionally useful for not only electric vehicle conversions but things like off-grid energy storage.

A little over a year ago we featured a similar teardown for the battery back in the Tesla Model S, as well as the incredible project that built a working car from multiple wrecks.

[Thanks to DarksideDave for the tip.]

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