A Look Inside A Lemon Of A Race Car

May 21, 2025 by Fenix Guthrie 6 Comments

Automotive racing is a grueling endeavor, a test of one’s mental and physical prowess to push an engineered masterpiece to its limit. This is all the more true of 24 hour endurance races where teams tag team to get the most laps of a circuit in over a 24 hour period. The format pushes cars and drivers to the very limit. Doing so on a $500 budget as presented by the 24 hours of Lemons makes this all the more impressive!

Of course, racing on a $500 budget is difficult to say the least. All the expected Fédération Internationale de l’Automobile (FIA) safety requirements are still in place, including roll cage, seats and fire extinguisher. However, brakes, wheels, tires and safety equipment are not factored into the cost of the car, which is good because an FIA racing seat can run well in excess of the budget. Despite the name, most races are twelve to sixteen hours across two days, but 24 hour endurance races are run. The very limiting budget and amateur nature of the event has created a large amount of room for teams to get creative with car restorations and race car builds.

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LEGO Race Car Simulator Is Like A Mechanical Arcade Game

November 14, 2022 by Lewin Day 6 Comments

We’ve all played some variant of that simple old racing video game. It’s the one that involves swerving around cars in front without crashing, as the pace steadily increases further. [Dr. Engine] has recreated that very game in the physical world, with the help of LEGO Technic.

The design uses what appears to be a LEGO tank tread to create a treadmill for a LEGO car. The initial design is hand-cranked, but [Dr. Engine] soon upgrades this with a motor. The wide treadmill is then fitted with a steering wheel. This steers the car laterally along the treadmill via a simple pulley system. From there, it was a simple job of adding gearbox to change the speed of the treadmill, and obstacles for the car to dodge. Double-sided table affixed small die-cast cars to the track to fit the theme of the build.

It’s great fun watching the car buck and weave over the undulating track, and we’d certainly love to compete with friends for the high score. We’ve seen similar builds before, too, like this all-LEGO suspension dyno. Video after the break.

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What It Takes: Turning A Hatchback Into A Race Car

November 17, 2021 by Lewin Day 24 Comments

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 CityCar Cup championship aims to keep entry costs low and racing competitive by racing cheap hatchbacks with a strict ruleset. Credit: Nankang Tyre CityCar Cup

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.

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Formula 1 TV Broadcasting In 1:87 Scale

June 18, 2021 by Chris Lott 11 Comments

[Gerrit Braun], co-founder of the [Miniatur Wunderland] model railway and miniature airport attraction in Hamburg, takes his model building seriously. For more than five years, he and his team have been meticulously planning, testing, and building a 1:87 scale of Formula 1’s Monaco Grand Prix. Models at the Wunderland are crafted to the Nth detail and all reasonable efforts, and some unreasonable ones, are taken to achieve true-to-life results. In the video down below, part of Gerrit’s diary of the project, he discusses the issues and solutions to simulating realistic television broadcasts (the video is in German, but it has English language subtitles).

The goal is to model the large billboard-sized monitor screens set up at viewing stands. In real life, these displays are fed with images coming in from cameras located all over the circuit, the majority of which are operated by a cameraman. The miniaturization of cameras has come a long way in recent years — the ESP32-CAM module or the Raspberry Pi cameras, for example. But miniaturizing the pan-and-tilt actions of a cameraman, while perhaps possible, would not be reliable over the long time (these exhibits at Wunderland are permanent and operate almost daily). Instead, the team is able to use software to extract a cropped window from high-resolution video, and moving the position of this cropped window simulates the pointing of the camera. More details are in the video.

The skill and creativity of [Gerrit] and his team is incredible. Other videos on this project cover topics like the sound system, PCB techniques used for the roads, and the eye-popping use of an electric standing desk to lift an entire city block so workers can gain access to the area. Fair warning — these are addictive, and the video below is #76 of an unfinished series. We wrote about Wunderland back in 2016 when [Gerrit] and his twin brother [Frank] teamed with Google Maps to make a street view of their replica cities. Thanks to [Conductiveinsulation] who sent us the tip, saying that the discussion about interconnected triangular PCB tiles on this week’s Podcast #122 reminded him of this for some reason. Have any of our readers visited Miniatur Wunderland before? Let us know in the comments below.

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Charging An Electric Supercar With Lemons, Kids, And The Sun

June 29, 2018 by Dan Maloney 27 Comments

First things first: the tease on this video, that an electric supercar can be charged from a massive lemon battery array, is exactly that – a tease. Despite that, it makes for an interesting story and a great attempt to get kids exposed to science and engineering.

The story goes that [Mark] was approached by Volkswagen to help charge the batteries on their entry for the upcoming Pikes Peak International Hill Climb, the annual “Race to the Clouds” in Colorado. Racers are tortured by a 4,700′ (1,440 m) vertical climb over a 12.42 mile (20 km) course that features 156 switchback turns. Volkswagen’s entry is an electric supercar, and they sent [Mark] a portable battery cart to charge up the best way he saw fit.

Teaming up with [William Osman], the first attempt was a massive array of lemon cells, made with waterjet-cut strips of zinc and copper held in a plywood frame. Studded with 1,232 lemons, the battery performed just about as well as you’d expect it would. Plan B was cute, and another of [Mark]’s attempts to pad his “Funnest Uncle Ever” score a bit. He devised a zip line with regenerative braking to charge a cordless drill battery, and then indirectly harvested the energy in the battery by turning it into lemonade for a bunch of kids. The sugared-up kids rode the zip line till the battery was charged.

That was still a drop in the bucket, though, so Plan C saw [Mark] install a large solar array on his roof; the tie-in here was that the lemon-powered kids got to design a cleaning system for the solar array. A weak link, to be sure, but the kids had fun, and we can’t deny that the car will at least be partially lemon-powered when it heads up the hill.

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Vietnam War Helicopter Turned Amphibious Racecar

October 31, 2016 by Steven Dufresne 33 Comments

Our hats off to [SpeedyCop] and his [Gang of Outlaws] for turning a junked former Vietnam War helicopter into both an amphibious vehicle and a road race car. Yes, that’s right. It’s both driven on water and raced in the 24 Hours of LeMons at New Jersey Motorsports Park.

It started life as a 1969 Bell OH-58 Kiowa (US Army Vietnam Assault helo) and had not only served in Vietnam but also for a federal drug task force. It was chopped up for parts and the body found its way to [SpeedyCop] and friends. The body now sits on an 80s Toyota van chassis, has a Mazda Miata rear suspension, and Audi 3.0 V6 engine.

The pontoons were originally added to hide the seam between the helicopter body and the van but they then inspired the idea of making it amphibious. And with the addition of a four-blade, 7000 RPM propeller from a parasail boat, the idea became reality, as you can see in the video after the break (we suspect the trailing line is a rope to pull it back to shore in case of engine failure).

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Forty-Year-Old Arcade Game Reveals Secrets Of Robot Path Planning

April 28, 2016 by Dan Maloney 20 Comments

What’s to be gained from reverse engineering a four-decade-old video game? As it turns out, quite a lot, and as you’ll learn from [Norbert]’s recent talk at the ViennaJS meetup, it’s not just about bringing a classic back to life.

The game in question is Kee Game’s Sprint 2, a monochrome 2D car race that allowed two players to compete head to head. The glorious Harvest Gold and Burnt Orange color scheme just screams 1970s, and it might be hard to see why this game was once a popular quarter-eater. But it was quite engaging for the day, and [Norbert] was interested in reverse engineering it. That he did, using JavaScript to build a faithful browser-based emulation of the game. And he took it further, creating a 3D first-person version of the game.

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