Modified Car Alternator Powers Speedy DIY E-Bike

October 25, 2021 by Tom Nardi 38 Comments

Your garden variety automotive alternator is ripe for repurposing as is, but with a little modification, it can actually be used as a surprisingly powerful brushless motor. Looking to demonstrate the capabilities of one of these rebuilt alternators, [DIY King] bolted one to the back of a old bicycle and got some impressive, and frankly a bit terrifying, results.

We should say up front that the required modifications to the alternator are quite extensive, so before you get too excited about building your own budget e-bike, you should check out the previous guide [DIY King] put together. The short version is that you’ll need to machine a new rotor and fill it with the neodymium magnets salvaged from hoverboard motors.

A custom built alternator rotor is the key to the project.

Once you’ve got your modified alternator, the rest is relatively easy. The trickiest part of this build looks like it was cutting off the bike’s rear wheel mount and replacing it with a plate that holds the alternator and a pair of reduction gears pulled from a 125cc motorbike. Beyond that, it’s largely electronics.

Naturally, you’ll also need a pretty beefy speed controller. In this case [DIY King] is using a 200 amp water-cooled model intended for large RC boats, though interestingly enough, it doesn’t seem he’s actually running any water through the thing. He’s also put together a custom 1,500 watt-hour battery pack that lives in a MDF box mounted under the seat.

To test out his handiwork, [DIY King] took to the streets and was able to get the bike up to 70 km/h (43 MPH) before his courage ran out. He thinks the motor should be able to push it up to 85 km/h, but he says the bike started wobbling around too much for him to really open it up. In terms of range, he calculated that while cruising around at a more palatable 30 km/h (18 MPH), he should be able to get 100 kilometers (62 miles) off of a single charge.

If you like repurposed motors and suicidal bike speeds, you’ll love this build that uses a washing machine motor to push a rider to a claimed 110 km/h. If you’re not worried about speed or range, then this supercapacitor e-bike is certainly worth a look as well.

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

October 25, 2021 by Adam Fabio 21 Comments

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

October 21, 2021 by Jenny List 43 Comments

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)

October 11, 2021 by Al Williams 23 Comments

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

October 11, 2021 by Dan Maloney 46 Comments

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

October 10, 2021 by Jenny List 30 Comments

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

October 10, 2021 by Al Williams 34 Comments

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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