Bridging The Gap Between Dissimilar Road Types With Foam

When you think of driving up or down an embankment, do you ever wonder how much foam you’re currently driving on? Probably not, because it hardly seems like a suitable building material. But as explained by [Practical Engineering] in the video below the break, using an expanded material to backfill an embankment isn’t as dense as it sounds.

In many different disciplines, mating dissimilar materials can be difficult: Stretchy to Firm; Soft to Hard; Light to Heavy. It’s that last one, Light to Heavy, that is a difficult match for roadways. A bridge may be set down in bedrock, but the embankments approaching it won’t be. The result? Over time, embankment settles lower than the bridge does, causing distress for cars and motorists alike. What’s the solution?

To mitigate this, engineers have started to employ less dirty materials to build their otherwise soil based embankments. Lightweight concrete is one solution, but another is Expanded Polystyrene (EPS) foam. Its light weight makes installation simple in anything but a strong breeze, and it’s inexpensive and durable. When used properly, it can last many years and provide a stable embankment that won’t settle as far or as quickly as one made of dirt. Because as it turns out, dirt is heavy. Who knew?

Aside from roadways and bespoke aircraft, EPS foam has also been used for making home insulation. What’s your favorite use for EPS foam? Let us know in the comments below.

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Reverse Engineering British Rail Tickets

There was a time when to take a British rail journey was to receive a ticket barely changed since Victorian times — a small cardboard rectangle printed with the destination through which the inspector on the train would punch a hole. In recent decades these were replaced by credit-card-sized thin card, and now increasingly with scanable 2D codes from an app. These caught the attention of [eta], and she set about reverse engineering their operation.

The codes themselves are Aztec barcodes, similar to a QR code but with a single central fiducial mark. At first glance they resemble the codes used by non-UK ticketing systems, but she soon found out that they don’t follow the same standard. There followed a lengthy but fascinating trail of investigation, involving app decompilation of a dodgy copy of the ticket inspector app to find public keys, and then some work with a more reputably sourced app from another ticketing company.

Along the way it revealed a surprising amount of traveler data that maybe shouldn’t be in the public domain, and raises the question as to why the ticketing standard remains proprietary. It’s well worth a read.

If you’d like more UK rail ticket hacking, it formed the subject of a talk at EMF 2022.

A white longtail cargo bike sits on grass with fenced-in planters behind it. The bike has a basket made of black metal tubes on the front and a passenger compartment behind the rider seat for children made of similar black metal tubes. A white canopy is above the passenger compartment and a solar panel sits atop the canopy.

Solar Powered E-bike Replaces Car Trips

E-bikes can replace car trips for some people, and adding a solar panel can make the fun last longer. [Luke] did some heavy modifications to his RadWagon to make it better, stronger, and faster than it was before.

The first step was replacing the stock 750 W controller with a 1500 W model to give the motor twice the power. [Luke] plans to replace the motor if it gets fried pushing too much juice, but is planning on just being careful for now. To stop this super-powered ride, he swapped the stock mechanical discs out for a hydraulic set which should be more reliable, especially when loading down this cargo bike.

On top of these performance enhancements, he also added a 50 W solar panel and maximum power point tracking (MPPT) charge controller to give the bike a potential 50% charge every day. Along with the OEM kid carrier and roof, this bike can haul kids and groceries while laughing at any hills that might come its way.

Checkout this other solar e-bike or this one making a trip around the world for more fun in the sun.

China’s New 100 MPH Train Runs On Hydrogen And Supercaps

Electric cars are very much en vogue right now, as the world tries to clean up on emissions and transition to a more sustainable future. However, these vehicles require huge batteries as it is. For heavier-duty applications like trucks and trains, batteries simply won’t cut the mustard.

Normally, the solution for electrifying railways is to simply string up some wires and call it a day. China is trying an alternative solution, though, in the form of a hydrogen-powered train full of supercapacitors.

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Driverless Buses Take To The Road In Scotland

Scotland! It’s the land of tartans, haggis, and surprisingly-warm kilts. It’s also ground zero for the first trial of full-sized driverless buses in the United Kingdom.

It’s not just automakers developing driverless technologies. Transit companies are desperate to get in on the action because it would completely upend their entire existing business structure. Now that self-driving buses are finally approaching a basic level of competence, they’re starting to head out to haul passengers from A to B. Let’s look at how the UK’s first driverless bus project is getting on out in the real world. 

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A black quadcopter sits on a grey surface. In place of traditional propellers are four figure eight propellers with sharp tips where the top and bottom of the eight would be.

Toroidal Propellers Make Drones Less Annoying

Despite being integral to aviation for more than a century, propellers have changed remarkably little since the Wright Brothers. A team at MIT’s Lincoln Lab has developed a new propeller shape that significantly reduces the noise associated with drones. [PDF via NewAtlas]

Inspired by some of the experiments with “ring wings” in the early 20th Century, researchers iterated on various toroidal propeller geometries until arriving at one that significantly reduces the sound produced by the rotors, particularly in the range of human hearing. The team suspects the reduction in noise is due to vortices being distributed over the whole propeller instead of just the tips.

Experiments show the drones can get twice as close before becoming a nuisance for human ears which should be great news for anyone hoping to launch Skynet commercial drone deliveries. Since the rotors are easily fabricated via 3D printing they should be easy to adapt to a number of different drones.

If you want to explore some more interesting drones, checkout this one that can fly and swim or this one that only uses a single propeller.

ADS-B Exchange Sells Up, Contributors Unhappy

In the news among aviation enthusiasts, the ADS-B data aggregation and aircraft tracking site ADSB-Exchange has been sold by its founder to JETNET for a reported $20,000,000. This type of routine financial news is more at home in the business media than on Hackaday, but in this case there’s something a little different at play. ADS-B Exchange is a community driven site whose data comes from thousands of enthusiasts worldwide connecting their ADS-B receivers to its feed API. The sale to a commercial flight data company has not gone down well with this community who are unsurprisingly unimpressed that their free contributions to the website have been sold.

This certainly isn’t the first time a site built on community data has flipped into big business, and while it’s unclear whether JETNET will do a full CDDB and boot out anyone not paying to play, we can understand the users feeling that their work has been sold from under them. On the other hand, how many of us can truly claim their open source beliefs wouldn’t start to buckle once somebody slides a $20m check across the table?

It’s evidently too late for anyone aggrieved by their ADS-B data being sold, but perhaps there’s something else to think about here. We have an established way to recognize open source software in the many well-known software libre licences, but we don’t for crowd-sourced data. Perhaps it’s time for the open-source community to consider this problem and come up with something for future sites like ADS-B Exchange whatever field they may be in, a licence which clearly defines the open terms under which contributors provide the data and those under which site owners can use it. Otherwise we’ll be here again in a few years writing about another aggrieved community, and we think that doesn’t have to happen.