As we’ve learned from past experience, videos from [HowToLou] tend to be a bit controversial. His unique style of expedient engineering isn’t everyone’s cup of tea, especially when it’s combined with a devil-may-care attitude towards safety. On the other hand, there’s no arguing that his methods get results. His video on converting an 18 HP riding mower into something akin to a go-kart is a perfect example.
The first phase of the project involves removing all the hardware related to mowing, as obviously you won’t be cutting any grass while pushing speeds of 48 kph (30 mph). This both saves weight, and removes a lot of mechanical complication that would be in the way of further modification. That said, it also leaves the mower immobile, as there’s no longer be any connection between the engine and transaxle.
In its place, [HowToLou] installs an off-the-shelf torque converter kit that uses a continuously variable transmission (CVT) clutch. As he quickly demos, the CVT technology allows the gear ratio to automatically adapt to the engine RPM thanks to pulleys that change their size depending on how fast they’re spinning. It’s a big improvement over the system he originally yanked out, though as you might expect, fitting it into the mower required some custom work. The final step was to pull the old pulley off of the transaxle and replace it with one that’s less than half the original size.
Wearing his protective flip-flops, [HowToLou] hops on the souped-up mower and is nearly thrown off the back of it as soon as he steps on the gas. Clearly the modifications were a success, and the video ends with some open road testing — presumably he’s riding off to the store to go buy a helmet.
We actually missed this video when it first made the rounds, but it has since picked up steam and is pulling in some impressive numbers. [HowToLou] tells us he thinks it’s due to the fact that a lot of people are upgrading to more modern zero-turn mowers, meaning there’s a surplus of these second-hand mini tractors on the market. Whatever the reason, we’re happy to see this backyard engineer get some mainstream success; his methods might not always be by the book, but they’re always entertaining.
When you hear raytracing, you might think of complex dark algorithms that to stare too long at their source code invites the beginning of madness. And you’re technically not far off from the truth, but [h3r2tic] put a small open-source ray tracing game demo up on GitHub. The actual rust code powering the game is relatively short (just four files), with the longest file being the physics file. But, of course, there is a small mountain of code under this sample in the form of libraries.
Kajiya, physx-rs, and dolly are the three libraries that make this little demo possible. Kajiya, in particular, is what makes raytracing possible as it uses the newer RTX features (so only more recent Nvidia and AMD cards are supported) and Vulkan bindings. But, of course, it isn’t wholly ray-traced as we are still several years out from proper real-time raytracing. Nevertheless, the blend between raytracing and traditional rasterization looks incredible. The most important thing about this simple tiny sample isn’t the game itself but what it stands for. It shows how easy it is to create a sample like this. Even just five years, creating a demo like this required massive effort and expertise.
Visually, it is stunning to look at. While the reflections are most apparent, the takeaway from this is the ease that real-time global illumination brings. A quick look through the code shows that there are very few lights in the scene, despite looking well lit with soft shadows. Traditional video games spend a significant amount of development time lighting a scene, placing additional lights, and tweaking them to make up for all the shortcuts that lighting has to take in a rasterized environment. As more and more games are built with raytracing in mind rather than tacked on at the end, we can ditch the small crumbling mountain of hacks that we are forced to use in games today and just rely on the rays to accurately light a scene.
As the world grapples with the issue of climate change, there’s a huge pressure to move transport away from carbon-based fuels across the board. Whether it’s turning to electric cars for commuting or improving the efficiency of the trucking industry, there’s much work to be done.
It’s a drop in the ocean in comparison, but the world of motorsports has not escaped attention when it comes to cleaning up its act. As a result, many motorsports are beginning to explore the use of alternative fuels in order to reduce their impact on the environment.
We’ve spoken a lot about building race cars here at Hackaday, but what does it actually look like to go out and do it? The boys from [Bad Obsession Motorsport] dived into that very question with their Bargain Racement series last year.
The series follows the duo as they build a Citroen C1 into a competitive race car to take on the City Car Cup, an entry-level racing series focused on keeping the field competitive and the racing close.
Even at this level, there’s plenty to do to prep the car for competition. The rollcage needs to be installed, seats changed out for race-spec gear, and plenty of wiring to do as well. [Nik] and [Richard] have plenty of experience in the field of motorsport, and shine a great light on how to do the job, and do it right.
All in all, building the car cost £5995 pounds, starting from a used £850 Citroen C1. However, actually going racing costs more than that. Between race suits and boots, a helmet, club memberships and race entry fees, it cost a full £8273 to get to the first race. It’s steep, though much of those costs are upfront. Keep the car off the walls and year on year, you only need to keep paying for entry fees, memberships and consumables like fuel and tires.
It’s a great look at everything from building a race car, to testing and then actually competing as well. It serves as an excellent real-world example of what we talk about in our series on how to get into cars, which just recently touched on prepping a car for endurance competition. Video after the break.
Motorcycle rally racing is a high-speed, exciting, off-road motorsport that involves zipping across all types of terrain on two wheels. While riding, it’s extremely important for riders to know what’s coming up next — turns, straightaways, stream crossings, the list goes on. Generally, this is handled by a roadbook — a paper scroll that has diagrams of each turn or course checkpoint, along with the distances between them and any other pertinent information. Of course, this needs to be paired with a readout that tells you how far you’ve traveled since the last waypoint so you’re not just guessing. This readout usually takes the form of a rally computer, a device that can display speed, distance traveled, and course heading (and some of the fancier ones have even more data available).
Frustrated with the lackluster interface and high cost associated with most rally computers on the market, [Matias Godoy] designed his own back in 2017, and was quick to realize he had a potential product. After several iterations he brought his idea to market with a small initial run, which sold out in a few hours!
[Matias]’s project, the Open Rally Computer (formerly the Baja Pro) packages neatly in a CNC-machined case and features a nice high-visibility LCD display, a built-in GPS receiver, and an ergonomic handlebar-mounted remote. The data is crunched by an ESP32 microcontroller, which also allows for WiFi-enabled OTA updates. The end result is a beautiful and useful device that was clearly designed with great care. Love the idea but not a rally racer? If street bikes are more your thing then fear not because there’s an open source digital dashboard out there for you too.
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.
If you desire a sim gaming rig, there are off-the-shelf options up and down the market that stretch as high as your budget can afford. Some choose to eschew this route, however and build their own from scratch. Few people go quite so far as [Popicasa POPStuDio], however.
The first version of the rig is about as hacked as you can possibly get, and it’s a joy to see it built from scrap. The wheel itself and the pedals are all built out of old PVC pipe, with a bunch of old wood screwed together for the frame. A cheap USB gamepad serves to handle input to the PC for the pedals and H-shifter. The H-shifter uses simple power switches, repurposed in an ingenious way to sense gear position. The knob itself is cast out of what appears to be hot glue. Steering is done by connecting the wheel to a flexible shaft that tips a smartphone back and forth, using its internal accelerometers and gyros to sense rotation. It’s not clear how this is tied into the PC running Project CARS, but it’s impressive nonetheless.
Version 2 of the build takes things up a notch, using an Arduino Leonardo to handle steering and pedal functions as a Human Interface Device. There’s also force feedback, via a hefty motor attached to the steering shaft via a belt drive. This version implements an H-shifter as well as paddle shifters too for a more modern experience.
Both builds are unique in the modern era for eschewing CNC or 3D printed parts. It’s all done by hand, taking days of effort, and using only basic tools. It’s refreshing to see such a complex build done with nothing but simple materials and sheer commitment. We’re sure [Popicasa POPStuDio] enjoys the rig, and we can’t wait to see where it goes next. Perhaps the next iteration will even feature a motion platform, perhaps built out of old forklift parts? Only time will tell. Video after the break.