DIY Airless Tires Work Surprisingly Well

Airless tires have been “a few years away” from production for decades now. They’re one of the automotive version of vaporware (at least those meant for passenger vehicles), always on the cusp of being produced but somehow never materializing. They have a number of perks over traditional air-filled tires in that they are immune to flats and punctures, and since there aren’t any airless tires available at the local tire shop, [Driven Media] decided to make and test their own.

The tires are surprisingly inexpensive to make. A few pieces of drainage tubing of varying diameters, cut to short lengths, and then bolted together with off-the-shelf hardware is all it takes, although they note that there was a tremendous amount of hardware needed to fasten all the pipe lengths together. With the structure in place they simply cut a tread off of a traditional tire and wrapped it around each of the four assemblies, then bolted them up to their Caterham street-legal race car for testing.

While the ride quality was notoriously (and unsurprisingly) rough and bumpy, the tires perform admirably under the circumstances and survive being driven fairly aggressively on a closed-circuit race course. For such a low price and simple parts list it’s shocking that a major tire manufacturer like Michelin hasn’t figured out how to successfully bring one to a light passenger car yet.

Thanks to [Itay] for the tip!

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Bike On Over To The Campground

Like many of us, [Paul] enjoys occasionally hitching up his tow-behind camper and heading out to the wilderness to get away from it all at his favorite campsite. Unlike the vast majority of those who share his passion for the outdoors, though, [Paul] is hitching his camper up to a bicycle. Both the camper and the bike are custom built from the ground up, and this video shows us a little more details on [Paul]’s preferred mode of transportation.

While he is known for building custom vehicles of one sort or another, this latest one is a more traditional bicycle frame that he has modified only slightly to fit a recumbent-style seat and a small gas-powered motor. Even though the motor is decades old, it started right up and gives the power needed to pull the custom camper. [Paul] builds one-person campers like this out of corrugated plastic for durability and light weight, and this one is specifically designed for his size and sleeping style. It includes everything needed for a night under the stars, too, including a stove, storage compartments, and a few windows.

With the bike and camper combined weighing in at just over 200 pounds, the motor can be used as a pedal-assist device thanks to the clever engineering behind a front-wheel-drive pedal system on this bike. With all of that custom fabrication, [Paul] is free to head out to the wilderness without all the encumbrances (and high price) of traditional motor vehicle-based camping. For those curious about some of [Paul]’s other vehicle creations, take a look at this tiny speedboat for one.

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RC Snowmobile Makes Tracks On Ice

With all the futuristic technology currently at our disposal, it seems a little bizarre that most passenger vehicles are essentially the same thing that they were a century ago. Four wheels, a motor, and some seats would appear to be a difficult formula to beat. But in the 3D printing world where rapid prototyping is the name of the game, some unique vehicle designs have been pushed out especially in the RC world. One of the latest comes to us from [RCLifeOn] in the form of a single-wheeled RC snowmobile.

While not a traditional snowmobile with tracks, this one does share some similarities. It has one drive wheel in the back printed with TPR for flexibility and it also includes studs all along its entire circumference to give it better traction on ice. There are runners in the front made from old ice skates which the vehicle uses for steering, and it’s all tied together with an RC controller and some lithium batteries to handle steering and driving the electric motor.

There were some design flaws in the first iteration of this vehicle, including a very large turning radius, a gearing setup with an unnecessarily high torque, and a frame that was too flexible for the chain drive. [RCLifeOn] was also testing this on a lake which looked like it was just about to revert to a liquid state which made for some interesting video segments of him retrieving the stuck vehicle with a tree branch and string. All in all, we are hopeful for a second revision in the future when some of these issues are hammered out and this one-of-a-kind vehicle can really rip across the frozen wastes not unlike this other interesting snowmobile from a decade ago.

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Improving More Leaf Design Flaws

[Daniel] was recently featured here for his work in improving the default charging mode for the Nissan Leaf electric vehicle when using the emergency/trickle charger included with the car. His work made it possible to reduce the amount of incoming power from the car, if the charging plug looked like it might not be able to handle the full 1.2 kW -3 kW that these cars draw when charging. Thanks to that work, he was able to create another upgrade for these entry-level EVs, this time addressing a major Leaf design flaw that is known as Rapidgate.

The problem that these cars have is that they still have passive thermal management for their batteries, unlike most of their competitors now. This was fine in the early ’10s when this car was one of the first all-electric cars to market, but now its design age is catching up with it. On long trips at highway speed with many rapid charges in a row the batteries can overheat easily. When this happens, the car’s charging controller will not allow the car to rapid charge any more and severely limits the charge rate even at the rapid charging stations. [Daniel] was able to tweak the charging software in order to limit the rapid charging by default, reducing it from 45 kW to 35 kW and saving a significant amount of heat during charging than is otherwise possible.

While we’d like to see Nissan actually address the design issues with their car designs while making these straighforward software changes (or at least giving Leaf owners the options that improve charging experiences) we are at least happy that there are now other electric vehicles in the market that have at least addressed the battery thermal management issues that are common with all EVs. If you do own a Leaf though, be sure to check out [Daniel]’s original project related to charging these cars.

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Custom Packet Sniffer Is A Great Way To Learn CAN

Whilst swapping out the stereo in his car for a more modern Android based solution, [Aaron] noticed that it only utilised a single CAN differential pair to communicate with the car as opposed to a whole bundle of wires employing analogue signalling. This is no surprise, as modern cars invariably use the CAN bus to establish communication between various peripherals and sensors.

In a series of videos, [Aaron] details how he used this opportunity to explore some of the nitty-gritty of CAN communication. In Part 1 he designs a cheap, custom CAN bus sniffer using an Arduino, a MCP2515 CAN controller and a CAN bus driver IC, demonstrating how this relatively simple hardware arrangement could be used along with open source software to decode some real CAN bus traffic. Part 2 of his series revolves around duping his Android stereo into various operational modes by sending the correct CAN packets.

These videos are a great way to learn some of the basic considerations associated with the various abstraction layers typically attributed to CAN. Once you’ve covered these, you can do some pretty interesting stuff, such as these dubious devices pulling a man-in-the-middle attack on your odometer! In the meantime, we would love to see a Part 3 on CAN hardware message filtering and masks [Aaron]!

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Inside A CAN Bus Mileage Manipulator

In the days of carburetors and leaf spring suspensions, odometer fraud was pretty simple to do just by disconnecting the cable or even winding the odometer backwards. With the OBD standard and the prevalence of electronics in cars, promises were made by marketing teams that this risk had all but been eliminated. In reality, however, the manipulation of CAN bus makes odometer fraud just as easy, and [Andras] is here to show us exactly how easy with a teardown of a few cheap CAN bus adapters.

We featured another project that was a hardware teardown of one of these devices, but [Andras] takes this a step further by probing into the code running on the microcontroller. One would imagine that basic measures would have been taken by the attackers to obscure code or at least disable debugging modes, but on this one no such effort was made. [Andras] was able to dump the firmware from both of his test devices and start analyzing them.

Analyzing the codes showed identical firmware running on both devices, which made his job half as hard. It looked like the code was executing a type of man-in-the-middle attack on the CAN bus which allowed it to insert the bogus mileage reading. There’s a lot of interesting information in [Andras]’s writeup though, so if you’re interested in CAN bus or attacks like this, it’s definitely worth a read.

Solar Panel Keeps Car Battery Topped Off Through OBD-II Port

Up until the 1980s or so, a mechanic could check for shorts in a car’s electrical system by looking for sparks while removing the battery terminal with everything turned off in the car. That stopped being possible when cars started getting always-on devices, and as [Kerry Wong] learned, these phantom loads can leave one stranded with a dead battery at the airport after returning from a long trip.

[Kerry]’s solution is simple: a solar trickle charger. Such devices are readily available commercially, of course, and generally consist of a small photovoltaic array that sits on the dashboard and a plug for the lighter socket. But as [Kerry] points out in the video below, most newer model cars no longer have lighter sockets that are wired to work without the ignition being on. So he chose to connect his solar panel directly to the OBD-II port, the spec for which calls for an always-on, fused circuit connected directly to the positive terminal of the vehicle battery. He had to hack together an adapter for the panel’s lighter plug, the insides of which are more than a little scary, and for good measure, he added a Schottky diode to prevent battery discharge through the panel. Even the weak winter sun provides 150 mA or so of trickle charge, and [Kerry] can rest assured his ride will be ready at the end of his trip.

We used to seeing [Kerry] tear down test gear and analyze unusual devices, along with the odd post mortem on nearly catastrophic failures. We’re glad nothing burst into flames with this one.

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