Modified Car Alternator Powers Speedy DIY E-Bike

October 25, 2021 by Tom Nardi 40 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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Mastering Memory For Microcontrollers: Elecia White To Deliver Remoticon Keynote

October 25, 2021 by Mike Szczys 1 Comment

I’m excited to share the news that Elecia White will deliver a keynote talk at the Hackaday Remoticon in just a few short weeks. Get your free ticket now!

Elecia is well-known throughout the embedded engineering world. She literally wrote the book on it — or at least a book on it, one I have had in my bedside table for reference for years: O’Reilly’s Making Embedded Systems: Design Patterns for Great Software. She hosts the weekly Embedded podcast which has published 390 episodes thus far. And of course Elecia is a principal embedded software engineer at Logical Elegance, Inc working on large autonomous off-road vehicles and deep sea science platforms.

Map of a mythical land used as a metaphor for microcontroller memory — Map metaphor used to help visualize microcontroller memory. [Source: embedded.fm]

For her keynote, Elecia plans to unwrap the secrets often overlooked in the memory map file generated when compiling a program for a microcontroller. Anyone who has written code for these mighty little chips has seen the .map files, but how many of us have dared to really dive in?

Elecia will use a nifty metaphor for turning the wall of text and numbers into a true map of the code. That metaphor makes the topic approachable for everyone with at least a rudimentary knowledge of how embedded systems work, and even the grizzliest veteran will walk away with tips that help when optimizing for RAM usage and/or code space, updating firmware (with or without a bootloader), and debugging difficult crash bugs.

This autumn is a busy time for Elecia. She’s been hard at work turning her book into a ten-part massive open online course (MOOC). Over the years she’s been a strong supporter of Hackaday, more than once as a judge for the Hackaday prize (here’s her tell-all following the final round judging of the 2014 Prize). She even took Hackaday on a tour of Xerox Parc.

Final Talk Announcements This Week and Next!

The Call for Proposals closed a few days ago. So far we’ve made two announcements about the accepted talks and we’ll make two more, this Thursday and next. But there’s no reason to wait. With Elecia White, Jeremy Fielding, and Keith Thorne presenting keynotes, and some superb social activities soon to be unveiled, this is an event not to be missed!

Remoticon is free to all, just head over and grab a ticket! If you want something tangible to remember the weekend by you can grab one of the $25 tickets that scores you a shirt, but either option gets you all the info you need to be at every virtual minute of the conference.

RC car without a top, showing electronics inside.

Fast Indoor Robot Watches Ceiling Lights, Instead Of The Road

October 25, 2021 by Donald Papp 15 Comments

[Andy]’s robot is an autonomous RC car, and he shares the localization algorithm he developed to help the car keep track of itself while it zips crazily around an indoor racetrack. Since a robot like this is perfectly capable of driving faster than it can sense, his localization method is the secret to pouring on additional speed without worrying about the car losing itself.

The regular pattern of ceiling lights makes a good foundation for the system to localize itself.

To pull this off, [Andy] uses a camera with a fisheye lens aimed up towards the ceiling, and the video is processed on a Raspberry Pi 3. His implementation is slick enough that it only takes about 1 millisecond to do a localization update, netting a precision on the order of a few centimeters. It’s sort of like a fast indoor GPS, using math to infer position based on the movement of ceiling lights.

To be useful for racing, this localization method needs to be combined with a map of the racetrack itself, which [Andy] cleverly builds by manually driving the car around the track while building the localization data. Once that is in place, the car has all it needs to autonomously zip around.

Interested in the nitty-gritty details? You’re in luck, because all of the math behind [Andy]’s algorithm is explained on the project page linked above, and the GitHub repository for [Andy]’s autonomous car has all the implementation details.

The system is location-dependent, but it works so well that [Andy] considers track localization a solved problem. Watch the system in action in the two videos embedded below.

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VCF East 2021: Novasaur TTL Computer Sets The Bar

October 25, 2021 by Tom Nardi 12 Comments

There was certainly no shortage of unique computers on display at the 2021 Vintage Computer Festival East; that’s sort of the point. But even with the InfoAge Science and History Museum packed to the rafters with weird and wonderful computing devices stretching back to the very beginning of the digital age, Alastair Hewitt’s Novasaur was still something of an oddity.

In fact, unless you knew what it was ahead of time, you might not even recognize it as a computer. Certainly not a contemporary one, anyway. There’s nothing inside its Polycase ZN-40 enclosure that looks like a modern CPU, a bank of RAM, or a storage device. Those experienced with vintage machines would likely recognize the tight rows of Advanced Schottky TTL chips as the makings of some sort of computer that predates the 8-bit microprocessor, but its single 200 mm x 125 mm (8 in x 5 in) board seems far too small when compared to the 1970s machines that would have utilized such technology. So what is it?

Inspired by projects such as the Gigatron, Alastair describes the Novasaur as a “full-featured personal computer” built using pre-1980 components. In his design, 22 individual ICs stand in for the computer’s CPU, and another 12 are responsible for a graphics subsystem that can push text and bitmapped images out over VGA at up to 416 x 240. It has 512 K RAM, 256 K ROM, and is able to emulate the Intel 8080 fast enough to run CP/M and even play some early 80s PC games.

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Soft Robotics Hack Chat

October 25, 2021 by Dan Maloney No comments

Join us on Wednesday, October 27 at noon Pacific for the Soft Robotics Hack Chat with Ali Shtarbanov!

By this point in technological history, we’ve all been pretty well trained in how to think about robots. Designs vary wildly, but to achieve their goals, most robots have one thing in common: they’re rigid. Whether it’s a robot arm slinging a spot welder on an assembly line or a robot dog on patrol, they’re largely made of stiff, strong, materials that, more often than not, are powered by electric motors of some sort.

But just because that’s the general design palette for robotics doesn’t mean there aren’t other ways. Robots, especially those that are intended to be used in close association with humans, can often benefit from being a little more flexible. And that’s where the field of soft robotics shines. Rather than a skeleton of machined aluminum and powerful electric actuators, these robots tend more toward silicone rubber construction with pneumatic activation. Some soft robots are even compliant and safe enough to be wearable, giving humans the ability to do things they never could before, or perhaps restoring functions that have been lost to the ravages of entropy.

Soft robotics is a fascinating field with the potential to really revolutionize things like wearables and collaborative robotics. To help us understand a little more about what’s going on in this space, we’re pleased to welcome Ali Shtarbanov to the Hack Chat. Ali is a Ph.D. student at MIT’s famed Media Lab, where he studies Human-Computer Interaction. He’s particularly interested in making soft robotics as fast and easy to prototype as traditional robotics have become, and to this end, he invented FlowIO, an open-source platform for pneumatic control. We’ll use this as a jumping-off point to discuss the whole field of soft robotics, especially where it is now and where Ali sees it going in the future.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, October 27 at 12:00 PM Pacific time. If time zones have you tied up, we have a handy time zone converter.

The Longest Ever Flight Was Over 64 Days In A Cessna 172

October 25, 2021 by Lewin Day 71 Comments

Often, when we think of long-endurance flights, our first thoughts jump to military operations. Big planes with highly-trained crew will fly for long periods, using air-to-air refuelling to stay aloft for extended periods.

However, many of the longest duration flights have been undertaken as entirely civilian operations. The longest of all happened to be undertaken by that most humble of aircraft, the Cessna 172. From December 1958 to February 1959, Bob Timm and John Cook set out to make history. The duo remained aloft for a full 64 days, 22 hours and 19 minutes, setting a record that stands to this day.

A Test of Endurance

One might expect that such an effort was undertaken to push the envelope or to strike new ground in the world of aerospace engineering. However, the real truth is that Bob Timm was a slot machine mechanic and former bomber pilot who worked at the Hacienda casino in Las Vegas. Proprietor Doc Bailey was always on the hunt for promotional ideas, and Timm pitched his boss that a record attempt in a plane bearing the casino’s branding would be a good way to go. Bailey agreed, and committed $100,000 to the effort.

Modifications to prepare the aircraft for the stunt took the best part of a year. The pint-sized Cessna was fitted with a 95-gallon belly tank, paired with a electric pump that could transfer fuel to the main wing tanks as needed. Special plumbing was also added that would allow the engine oil and filters to be changed while the engine was still running.

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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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