Chainless “Digital Drive” Bikes Use Electric Power Transmission Instead

December 23, 2022 by Lewin Day 140 Comments

We’re all familiar with how regular bikes work, with the pedals connected to the rear wheel via a simple chain drive. This setup is lightweight, cheap, and highly efficient. It’s not the only way to drive a bike though, and there’s plenty of buzz around the concept of “digital drive” bikes.

These drivetrains rely on electrical methods to transfer power in place of mechanical. The pedals are used to turn an electric generator, with power then sent to an electric motor which drives the rear wheel. The concept may sound overly complicated, but it does offer some benefits. The generator can change its operation to keep the rider pedalling at their most efficient, consistent rate. There would also be no chain to fall off, get snagged on clothing, or require regular maintenance.

It would make integrating regenerative braking possible, too, allowing the bike to harvest energy when going downhill too. This could be achieved with a storage battery or supercapacitor. As a bonus, it would be very easy to integrate power assist for the rider when tackling tough hills, for example. The lack of requirement for direct mechanical power transfer also means that there’s far more flexibility to design a bike with interesting geometry.

Such drive systems do give up some efficiency, however. All the power conversions between mechanical and electrical energy mean that a “digital drive” would likely only be 58% efficient. This compares poorly to the roughly 95% efficiency of power transfer in regular mechanically-driven bikes. There’s also a weight penalty, too.

Presnetly, there’s only one “digital drive” bike on the market – known as the Mando Footloose. It’s a swooping, folding, futuristic design, that has some feel issues when it comes to pedalling. And, given the added complexity and expense of these systems, it’s unlikely regular bikes or e-bikes are going away any time soon. Regardless, it’s fun to think about the potential for other drivetrain concepts to change the way we cycle. Video after the break.

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Hyundai To Lead US Market For Hydrogen Fuel Cell Trucks

December 13, 2022 by Lewin Day 96 Comments

Hydrogen has long been touted as a potential fuel of the future. While it’s failed to catch on in cars as batteries have taken a strong lead, it still holds great promise for larger vehicles like trucks.

Hyundai have been working diligently in this space over the last few years, with its Xcient line of fuel-cell powered trucks. It’s set to dominate the world of hydrogen trucking in the US as it brings a fleet of vehicles to California next year.

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Trash Bag And Foam Board Hovercraft Doesn’t Fail To Succeed. Or Fail.

December 5, 2022 by Ryan Flowers 23 Comments

When you think of a vehicle that can do it all- water, land, ice, snow and more- the hovercraft often comes to mind. And while they might not be ubiquitous, hovercraft catch the imagination of many a hacker just as it has for [JamesWhomsley] of [ProjectAir]. [James] has built a small, but just big enough hovercraft as you can see in the video below the break.

Starting with a small RC proof of concept, [James] tested out some of his favorite construction materials: foam board, trash bags, duct tape, and our personal favorite: hot glue! After a successful run with the radio controlled model, [James] set out to build a hovercraft big enough to carry a human.

The resulting hovercraft was definitely enough to take a human for a spin, despite still using RC airplane parts for power. Sure, there were a couple of instances of parts going flying, foamboard being shredded, and loss of control. Even so, the trash bag air skirt stayed intact, and the aforementioned damage was nothing some tape and hot glue couldn’t fix. [James] was back on the air in no time.

Of course, some of the very reasons that we don’t see hovercraft roaming the streets come up in the video, namely off-camber paths. But the build itself is quite good, and for those of us who’ve wondered what it takes to make a hovercraft, this video shows how the sausage is made.

This isn’t the first garbage bag based hovercraft, and we featured another RC/Arduino controlled version just a while back.

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This Electric Outboard Conversion Makes For A Quiet Day On The Water

November 29, 2022 by Dan Maloney 21 Comments

Nothing beats a day on the lake in a little boat with an outboard motor putt-putting along behind you. It’s great fun, if perhaps a little noisy with all that putting going on. And maybe that oily sheen on the water in your wake is not so nice. it could be that the fish are a little annoyed with your putting, too. Come to think of it, outboard motors are a bit of a problem.

Fortunately there’s a better way, like converting an old outboard motor to electric. It comes to us by way of [Anton], who happened upon the perfect donor platform — a 5-hp outboard by Crescent, sporting a glorious 1970s color scheme and a motor housing shell perfect for modding. He started by ripping the old engine and drivetrain out of the housing to make room for the BLDC motor and its driver. The motor was a project in itself; [Anton] rewound the original stator with much thicker wire and changed the coil configuration to milk as much torque as possible out of it. What started as a 180-kv motor ended up at 77 kv with much more copper and new Hall sensors for the controller. He also put a ton of effort into waterproofing the motor with epoxy resin. With a 3D-printed prop and a streamlined fairing, the new motor looks quite at home on the outboard. In fact, the whole thing barely looks customized at all — the speed control is even right on the tiller where you’d expect it.

The video below shows the build and a test run, plus an analysis of the problems encountered, chief of which is water intrusion. But as [Anton] rightly points out, that’s easily solved by reusing the original driveshaft and mounting the motor above the waterline, like this. Still, we like the look of this, and the idea of knocking around on the water nearly silently seems wonderful.

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Bicycle Gets Turn Signals And Brake Lights For Added Safety

November 28, 2022 by Bryan Cockfield 27 Comments

Traveling by bicycle can be a fun and exciting mode of transportation, and can also save a ton of money compared to driving a car. There are plenty of places around the world where a bicycle is the primary mode of transportation for a significant percentage of the population, but there are many more places that are designed entirely for cars with little thought given to anyone else. For anyone riding a bike, especially for people living in these car-dominated areas, additional safety measures like this LED array are often necessary.

The light array was created by [Estudio Roble] for traveling around his city. The design is based on the Adafruit Circuit Playground Express, which sits directly in the middle of the light fixture. Surrounding it is a diamond-shaped strip of LEDs within an additional ring. The light uses a bright blue color for normal driving, but is programmed to turn red when the accelerometer in the dev board detects braking. There are also integrated turn signals which operate similarly to motorcycle turn signals. The signal is sent wirelessly between the handlebar switch to the lights.

The device itself clips onto any backpack, and since the controller is wireless there are no wires to connect every time a rider gets on their bike. It’s quite an improvement over the complete lack of lighting on most bikes. If you’ve read this far, you need to check out this bicycle headlight which uses a projector to display information directly in the path of travel.

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an RGB LED display showing expected arrival times of trams and buses sitting on a table

A Private View Of A Public Transport Sign

November 12, 2022 by Abe Connelly 11 Comments

[Stefan Schüller] was a fan of the LED signs that display arrival information for the trams and buses in their city of Zürich. [Stefan] was having trouble finding a source to purchase the signs so, instead, decided to build one himself.

[Stefan] decided to recreate the 56×208 single color 2mm dot pitch display with an 128 x 64 P2 RGB LED screen respecting the same 2 mm pitch. The display is driven by an ESP32 DMA RGB LED matrix shield utilizing a HUB75 RGB LED matrix library, all being powered from a 5 V 4 A power supply.

In addition to driving the LED matrix display, the ESP32 polls Zürich’s public transportation API and then parses the XML for the relevant information. Since [Stefan] wanted to match the fonts as closely as possible,
he created a new font from scratch, including the bus and accessibility icons. The new font was encoded into a glyph bitmap distribution format (BDF) that was then converted to work with Adafruit’s GFX library, with [Stefan] creating a custom conversion tool, called bdf2adafruit, to do the last leg of the conversion.

Since the LED matrix had full color capability, [Stefan] decided to add a little extra flourish and color code the transportation lines with the official tram colors. All source code is available on his GitHub repository for the project, for those looking for more detail.

We’ve featured DIY builds of public transportation feeds before. With the ubiquity of low cost RGB LED displays and public APIs, hopefully we’ll see many more!

Concrete Boat Cements Its Way To High Speeds

November 11, 2022 by Ryan Flowers 12 Comments

Steel is scarce. Wood is not an option. And you need a boat now. These wartime circumstances drove innovation in all kinds of crazy directions, and one somewhat less crazy direction — concrete boats. As [Peter Sripol] demonstrates in the video below the break, making an RC concrete boat isn’t hard. Making a fast one on the other hand is. But that didn’t stop him from trying, and we think the effort deserves a look.

Starting with a basic displacement style hull, [Peter] and his cohorts experimented with a simple RC boat that worked, but could only move at slow speeds. They turned things up a notch or two and instead modeled their concrete boat after an RC speedboat hull that they had on hand.

The construction methods left a lot to be desired though, and they even tried various wire meshes as rebar, but they proved too heavy. Eventually though, they got a working hull, and had some fun with it. Rather than try to make the hull watertight with a rudder and propeller, they opted for a ducted fan and an airboat style rudder to make what they call the “world’s fastest concrete boat”.

Whether it’s the fastest or not is unconfirmed, but it is fast and actually gets on step fairly nicely. We applaud the exploration of alternative materials and the experimentation with different build methods. If building things with concrete floats your boat, then be sure to check out this concrete pinhole camera.

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