Bike Computer Powers On Long After Your Legs Give Out

August 20, 2020 by Brian McEvoy 13 Comments

A typical bicycle computer from the store rack will show your speed, trip distance, odometer, and maybe the time. We can derive all this data from a magnet sensor and a clock, but we live in a world with all kinds of sensors at our disposal. [Matias N.] has the drive to put some of them into a tidy yet competent bike computer that has a compass, temperature, and barometric pressure.

The brains are an STM32L476 low-power controller, and there is a Sharp Memory LCD display as it is a nice compromise between fast refresh rate and low power. E-paper would be a nice choice for outdoor readability (and obviously low power as well) but nothing worse than a laggy speedometer or compass.

In a show of self-restraint, he didn’t try to replace his mobile phone, so there is no GPS, WiFi, or streaming music. Unlike his trusty phone, you measure the battery life in weeks, plural. He implemented EEPROM memory for persistent data through power cycles, and the water-resistant board includes a battery charging circuit for easy topping off between rides.

When you toss the power of a mobile phone at a bike computer, someone will unveil the Android or you can measure a different kind of power from your pedals.

Continue reading “Bike Computer Powers On Long After Your Legs Give Out” →

The Mostly Forgotten Story Of Atmospheric Railway

August 17, 2020 by Jenny List 58 Comments

It doesn’t matter whether you know it as a railway, a railroad, a chemin de fer, or a 铁路, it’s a fair certainty that the trains near where you live are most likely to be powered either by diesel or electric locomotives. Over the years from the first horse-drawn tramways to the present day there haven’t been many other ways to power a train, and since steam locomotives are largely the preserve of museums in the 21st century, those two remain as the only two games in town.

But step back to the dawn of the railway age, and it was an entirely different matter. Think of those early-19th-century railway engineer-barons as the Elon Musks and Jeff Bezos’ of their day, and instead of space and hyperloop startups their playground was rail transport. Just as some wild and crazy ideas are spoken about in the world of tech startups today, so it was with the early railways. One of the best-known of these even made it to some real railways, I’m speaking of course about the atmospheric railway.

These trains were propelled not by a locomotive, but by air pressure pushing against a piston in a partially evacuated tube between the tracks.

Continue reading “The Mostly Forgotten Story Of Atmospheric Railway” →

Our Trucks Won’t Need No Batteries! Electric Trucks Look To Overhead Wires For Power

August 11, 2020 by Jenny List 212 Comments

As the world grapples with the spectre of the so-called “hockey stick” graph of climate change, there have been a variety of solutions proposed to the problem of carbon emissions from sectors such as transport which have become inseparable from the maintenance of 21st century life. Sometimes these are blue-sky ideas that may just be a little bit barmy, while other times they make you stop and think: “That could just work!”.

Such an idea is that of replacing the diesel engines in trucks with electric motors powered not by batteries but from overhead cables. An electric tractor unit would carry a relatively small battery for last-mile transit, but derive its highway power by extending a pantograph from its roof to a high-voltage cable above the road. It’s extremely seductive to the extent that there have even been trials of the system in more than one country, but does it stack up to a bit of analysis?

Time’s Up For Those Big Rigs

Siemens and Scania are justifiably proud of their electrified stretch of autobahn and electric trucks in Germany.

One thing that should be obvious to all is that moving our long-distance freight around by means of an individual fossil-fuel-powered diesel engine for every 38 tonne or so freight container may be convenient, but it is hardly either fuel-efficient or environmentally friendly The most efficient diesel engines on the road are said to have a 43% efficiency, and when hauling an single load they take none of the economies of scale afforded to the diesel engines that haul for example a freight train. Similarly they spread any pollution they emit across the entirety of their route, and yet again fail to benefit from the economies of scale present in for example a power station exhaust scrubber. However much I have a weakness for the sight of a big rig at full stretch, even I have to admit that its day has passed.

The battery technology being pursued for passenger cars is a tempting alternative, as we’ve seen with Tesla Semi. But for all its technology that vehicle still walks the knife-edge between the gain in cost-effectiveness versus the cost of hauling around enough batteries to transport that quantity of freight. Against that the overhead wire truck seems to offer the best of both worlds, the lightness and easy refueling of a diesel versus the lack of emissions from an electric. In the idealised world of a brochure it runs on renewable wind, sun, and water power, so all our problems are solved, right? But does it really stack up?

Continue reading “Our Trucks Won’t Need No Batteries! Electric Trucks Look To Overhead Wires For Power” →

Boom Hopes To Reignite Supersonic Travel With XB-1

August 10, 2020 by Tom Nardi 69 Comments

Since the last Concorde rolled to a stop in 2003, supersonic flight has been limited almost exclusively to military aircraft. Many have argued that it’s an example of our civilization seeming to slip backwards on the technological scale, akin to returning to the Age of Sail. There’s no debating that we have the capability of moving civilian passengers and cargo at speeds above Mach 1 safely, it’s just something that isn’t done anymore.

Concorde on its final flight, November 2003

Of course to be fair, there’s plenty of good reasons why the sky isn’t filled with supersonic aircraft. For one, they’ve historically been more drastically expensive to build and operate than their slower peers. The engineering that goes into an aircraft that can operate for an extended period of time at supersonic speeds doesn’t come cheap, nor do the materials required. But naturally, the same could have been said for commercial jet aircraft at one time. With further development, the cost would eventually come down.

The real problem holding supersonic aircraft back is much more practical: they are just too loud. From the roar of their powerful engines on takeoff to the startling and sometimes even dangerous “sonic boom” they leave in their wake, nobody wants them flying over their homes or communities. In fact, civilian flight above Mach 1 over land has been outlawed in the United States for exactly this reason since 1973 under the Federal Aviation Administration’s regulation 91.817.

For any commercial supersonic aircraft to be viable, it needs to not only be much cheaper to build and operate than older designs, but it also needs to be far quieter. Which is exactly what Boom hopes to demonstrate with their XB-1 prototype. The sleek craft will never enter into commercial service itself, but if all goes according to plan during its 2021 test flights, it may prove that the state-of-the-art in aircraft design is ready to usher in a new era of supersonic civilian transport.

Continue reading “Boom Hopes To Reignite Supersonic Travel With XB-1” →

Electric Skateboard With Tank Tracks, From A Big 3D Printer

July 31, 2020 by Danie Conradie 4 Comments

One of the basic truths of ground vehicles is that they are always cooler with tank tracks. Maybe not better, but definitely cooler. [Ivan Miranda] takes this to heart, and is arguably the king of 3D printed tank projects on YouTube. He has built a giant 3D printed electric skateboard with tank tracks with the latest version of his giant 3D printer. Videos after the break.

The skateboard consists of a large steel frame, with tracked bogies on either end. Most of the bogie components are 3D printed, including the wheels and tracks, and each bogie is driven by a brushless motor via a belt. Some bends were added to the steel frame with just 3D printed inserts for his bench vice. The bogies are mounted to the frame with a standard skateboard truck, which allows it to steer like a normal skateboard, by tilting the deck. It looks as though this works well on a smooth concrete floor, but we suspect that turning will be harder on rough surface where the tracks can’t slide. We’ll have to wait for the next video for a full field test.

The large components for this skateboard were printed on [Ivan]’s MK3 version of his giant 3D printer. Although it’s very similar to the previous version, improvements were made in key areas. The sliding bed frame’s weight was reduced by almost 50%, and the wheels were rotated, so they ride on top of the extrusion below it, instead of on it’s side, which helps the longevity of the wheels. This also allows bed levelling to be done by turning the eccentric spacers on each of the wheels. The rigidity of base frame and x-axis beam were increased by adding more aluminium extrusions. Although he doesn’t explicitly mention the print volume, it looks to be the same as the previous version, which was 800x500x500. For materials other than PLA, we suspect a heated build chamber will be required have any chance of making big prints without excessive warping.

[Ivan] really likes big prints, with a number of 3D printed tanks, a giant nerf gun, and a sand drawing bot. Continue reading “Electric Skateboard With Tank Tracks, From A Big 3D Printer” →

Jet Airliner Nacelle Becomes A Unique Camper

July 25, 2020 by Jenny List 47 Comments

It’s possible that some of you will have thought about making a custom camper for yourselves. Some of you may even have gone as far as to build a teardrop caravan. It’s very unlikely though that you’ll have gone as far as [Steve Jones] though, who took an outer engine nacelle from a retired ex-RAF VC-10 airliner and converted it into a camper that is truly one of a kind.

On the face of it a jet engine nacelle should be an easy shell for such a project, but such a simplified view perhaps doesn’t account for the many vents, pipes, and hatches required by the engine in flight. Turning it into a waterproof housing for a camper was a significant job, which he has managed to do while leaving one set of engine access doors available as a large opening for a room with a view.

The nacelle is mounted on a narrowed former caravan chassis, and with an eye-catching window created from its former air intake and a very well executed interior fit-out it makes for a camper that many of us would relish trying for ourselves. You can see a video of it below the break, and we wish we could be lucky enough to encounter it in a campsite one summer.

We’ve shown you our share of campers over the years, but perhaps this 3D printed one has most appeal.

Continue reading “Jet Airliner Nacelle Becomes A Unique Camper” →

There’s An Engineer In Germany I’d Like A Word With; Tale Of A Crumbling Volkswagen Lock

July 20, 2020 by Jenny List 149 Comments

In common with quite a few in the hardware hacking community, I have a fondness for older vehicles. My “modern” ride is an older vehicle by today’s standards, a Volkswagen Polo 6N made in the late 1990s. It’s by my estimation a Good Car, having transported me reliably back and forth across the UK and Europe for several years.

Last week though, it let me down. Outside the church in a neighbouring village the driver’s door lock failed, leaving me with my igniton key stuck in the door, and a mildly embarrassing phone call to my dad to bring the Torx driver required to remove the assembly and release it. I am evidently not 1337 enough, I don’t carry a full set of Torx bits with me everywhere I go. The passenger side lock has never worked properly while I’ve had the car, and this is evidently my cue to sort it all out.

Continue reading “There’s An Engineer In Germany I’d Like A Word With; Tale Of A Crumbling Volkswagen Lock” →