Fail Of The Week: Alternator Powered Electric Go-Kart Doesn’t Go

What do you give a six-year-old who loves going fast but doesn’t like loud noises? Convert a gas go-kart to electric of course! (Video, embedded below.) That goal started [Robert Dunn] of Aging Wheels down a long path toward a go-kart that almost, but doesn’t quite… work.

If you’ve watched any of [Robert’s] videos, you know he doesn’t take the easy path. The man owns a Trabant and Reliant Robin after all. Rather than buy a battery pack, he built his own 5S24P pack from individual LiFePO4 cells. Those cells generally are spot welded, so [Robert] built an Arduino-controlled heirloom-quality spot welder. Now while the welder could handle thin nickel strips, it wasn’t up the task of welding high current nickel-plated copper. When attempts at a solution failed, [Robert] built a system of clamped copper bus bars to handle the high current connections for the batteries.

If batteries weren’t hard enough, [Robert] also decided he wasn’t going to use an off-the-shelf motor for this project. He converted a car alternator to operate as a brushless motor. We’ve covered projects using this sort of conversion before. Our own [Jenny List] even wrote a tutorial on it. [Robert] unfortunately has had no end of trouble with his build.

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British Licence Plate Camera Fooled By Clothing

It’s a story that has caused consternation and mirth in equal measure amongst Brits, that the owners of a car in Surrey received a fine for driving in a bus lane miles away in Bath, when in fact the camera had been confused by the text on a sweater worn by a pedestrian. It seems the word “knitter” had been interpreted by the reader as “KN19 TER”, which as Brits will tell you follows the standard format for modern UK licence plate.

It gives us all a chance to have a good old laugh at the expense of the UK traffic authorities, but it raises some worthwhile points about the fallacy of relying on automatic cameras to dish out fines without human intervention. Except for the very oldest of cars, the British number plate follows an extremely distinctive high-contrast format of large black letters on a reflective white or yellow background, and since 2001 they have all had to use the same slightly authoritarian-named MANDATORY typeface. They are hardly the most challenging prospect for a number plate recognition system, but even when it makes mistakes the fact that ambiguous results aren’t subjected to a human checking stage before a fine is sent out seems rather chilling.

It also raise the prospect of yet more number-plate-related mischief, aside from SQL injection jokes and adversarial fashion, we can only imagine the havoc that could be caused were a protest group to launch a denial of service attack with activists sporting fake MANDATORY licence plates.

Header image, based on the work of ZElsb, CC BY-SA 4.0.

IBM Attempts An Uncrewed Atlantic Crossing (Again)

IBM and a non-profit company, ProMare, failed to send their 49-foot Mayflower autonomous ship across the Atlantic back in June. Now they are almost ready to try again. The Mayflower will recreate the path of its more famous namesake.

The total voyage is set to take a month, but the last attempt developed mechanical problems after three days. Now they are running more sea trials closer to shore before attempting another crossing in 2022. Continue reading “IBM Attempts An Uncrewed Atlantic Crossing (Again)”

Automate The Freight: Autonomous Ships Look For Their Niche

It is by no means an overstatement to say that life as we know it would grind to a halt without cargo ships. If any doubt remained about that fact, the last year and a half of supply chain woes put that to bed; we all now know just how much of the stuff we need — and sadly, a lot of the stuff we don’t need but still think we do — comes to us by way of one or more ocean crossings, on vessels specialized to carry everything from shipping containers to bulk liquid and solid cargo.

While the large and complex vessels that form the backbone of these globe-spanning supply chains are marvelous engineering achievements, they’re still utterly dependent on their crews to make them run efficiently. So it’s not at all surprising to learn that some shipping lines are working on ways to completely automate their cargo ships, to reduce their exposure to the need for human labor. On paper, it seems like a great idea — unless you’re a seafarer, of course. But is it a realistic scenario? Will shipping companies realize the savings that they apparently hope for by having fleets of unmanned cargo vessels plying the world’s oceans? Is this the right way to automate the freight?

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A Bike Trailer For Any Expedition

One of the greatest challenges for a hardware hacker relying only on a bicycle for transport lies in the regular need to carry more than can be slung from the handlebars or on the luggage rack of your trusty steed. One of our favourite YouTube creators in our sphere, [Laura Kampf], has addressed this problem with a trailer for her electric bike made from a pair of second-hand wheelbarrows. She uses their buckets to make a clamshell box, and their wheels alongside a custom steel chassis to make the rest of the trailer.

As always with Laura’s work it’s a delight to watch, with some careful use of the cutting wheel to install hinges and vents in the upper bucket. Finishing touches are a chequer plate top for the trailer and a spare wheel mounted on the back for that extra-rugged look. Experience with wheelbarrow wheels suggests to us that the slightly more expensive ones with ball bearings are worth the investment over the plastic ones, but either way this is a bike trailer that means business.

We don’t see as many bike trailers as we’d like here at Hackaday, and those few we have are old enough to have succumbed to link-rot. Perhaps this project might tempt a few people to try their hand?

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Axial Flux Motors For Electric Vehicles

In the everything old is new again folder, [Lesics] has a good overview of axial flux motors. These are promising for electric vehicles, especially aircraft, since the motors should have high torque to weight ratio. The reason this is actually something old is that the early generators built by Faraday were actually of the axial flux type. Soon, though, radial flux generators and motors became the norm.

The simple explanation is that in a radial system, the magnetic flux lines are perpendicular to the axis of rotation. In the axial system, the flux lines are parallel to the axis of rotation. There’s more to it than just that of course, and the video below has nice animations showing how it all works.

While these are not very common, they do exist even today. The Lynch motor, for example, is a type of axial flux motor that dates back to 1979. Usually, the impetus for using an axial flux motor is the ease of construction, but with the right design, they can be quite efficient (up to 96% according to the video).

We’ve seen plenty of PCB motors and most of those are axial in design. Not all of them, though.

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Autonomous Ground Effect Vehicle Demonstrator Aims To Speed Up Maritime Shipping

Ground effect vehicles, or ekranoplans, have the advantage of being more efficient than normal aircraft and faster than boats, but so far haven’t been developed beyond experimental prototypes. Fortunately, this doesn’t stop companies from trying, which has led to a collaboration between [ThinkFlight] and [rctestflight] to create a small-scale demonstrator for the Flying Ship Company.

The Flying Ship Company wants to use unmanned electric ekranoplans as high-speed marine cargo carriers that can use existing maritime infrastructure for loading and unloading. For the scale model, [rctestflight] was responsible for the electronics and software, while [ThinkFlight] built the airframe. As with his previous ekranoplan build, [ThinkFlight] designed it in XFLR5, cut the parts from foam using a CNC hot wire cutter (which we still want a better look at), and laminated it with Kevlar for strength. One of the challenges of ground effect vehicles is that the center of pressure will shift rearward as they leave a ground effect, causing them to pitch up. To maintain control when moving into and out of ground effect, these crafts often use a large horizontal stabilizer high up on the tail, out of ground effect.

A major feature of this demonstrator is automatic altitude control using a LIDAR sensor mounted on the bottom. This was developed by [rctestflight] using a simple foam board ekranoplan and [Think Flighs]’s previous airframe, with some custom code added to ArduPilot. It works very well on smooth, calm water, but waves introduce a lot of noise into the LIDAR data. It looks like they were able to overcome this challenge, and completed several successful test flights in calm and rough conditions.

The final product looks good, flies smoothly, and is easy to control since the pilot doesn’t need to worry about pitch or throttle control. It remains to be seen if The Flying Boat will overcome the challenges required to turn it into a successful commercial craft, and we will be following the project closely.

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