R/C car

52 Articles

Little RC Car Project Takes Inspiration From Mario Kart

October 18, 2024 by 9 Comments

RC cars used to be pretty simple. They’d go forwards, backwards, and steer if you got a full-function toy. However, with modern technology, it’s pretty trivial to make them more advanced. [Stuck at Prototype] demonstrates that nicely with his little Micro Racer Cars.

Each little RC car has its own ESP32 running the show, hooked up with a motor controller running a small DC gear motor at each wheel. Power is from a lithium-polymer battery on board the car, which is charged via USB C. 3D-printed components form the chassis and body of the vehicle. [Stuck at Prototype] set the cars up so they could be controlled via a smartphone app, or via a custom RC controller of his own design. He liked the latter solution after he realized how hard apps were to maintain. He also gave the cars a little color sensor so they could detect color patches on the ground, so they could change their behavior in turn. This was to create gameplay like Mario Kart, where hitting a color patch might make the car go fast, go slow, or spin out.

The video goes into great detail about everything these tiny tabletop racers can do. The racer cars were initially intended to be a Kickstarter funded project, but it never quite reached its goal. Instead, [Stuck at Prototype] decided to release the designs online instead, putting the relevant files on Github.

We’ve seen some other neat RC projects before, too. Video after the break.

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RC Car Gets Force Feedback Steering

August 6, 2024 by 8 Comments

Remote-controlled cars can get incredibly fast and complex (and expensive) the farther into the hobby you get. So much so that a lot of things that are missing from the experience of driving a real car start to make a meaningful impact. [Indeterminate Design] has a few cars like this which are so fast that it becomes difficult to react to their behavior fast enough through sight alone. To help solve this problem and bridge the gap between the experience of driving a real car and an RC one, he’s added force feedback steering to the car’s remote control.

The first thing to tackle is the data throughput required to get a system like this working wirelessly. Relying heavily on the two cores in each of a pair of ESP32s, along with a long-range, high-speed wireless communications protocol called ESP-NOW, enough data from the car can be sent to make this possible but it does rely on precise timing to avoid jitter in the steering wheel. Some filtering is required as well, but with the small size of everything in this build it’s also a challenge not to filter out all of the important high-frequency forces. With the code written, [Indeterminate Design] turned to the 3D printer to build the prototype controller with built-in motors to provide the haptic feedback.

The other half of the project involves sensing the forces in the RC car which will then get sent back to the remote. After experimenting with a mathematical model to avoid having to source expensive parts and finding himself at a deadend with that method, eventually a bi-directional load cell was placed inside the steering mechanism which solved this problem. With all of these pieces working together, [Indeterminate Design] has a working force feedback steering mechanism which allows him to feel bumps, understeer, and other sensations, especially while doing things like drifting or driving through grass, that would be otherwise unavailable to drivers of RC cars. The only thing we could think of to bring this even more into realistic simulation territory would be to add something like a first-person view like high-speed drones often have.

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3D-Printed RC Drift Car Comes With Smoke Effects

July 25, 2024 by 7 Comments

Drift cars are cool, but they’re also expensive. If you don’t have money for endless tires, fuel, and engine rebuilds, you might like to get involved at the RC scale instead. [Max Imagination] has just the build to get you started.

The design uses 3D printing for the majority of the chassis. Rigidity is front of mind, as is creating the right  steering and suspension geometry for smooth, controllable drifts. The drivetrain is 3D-printed too, using plastic gears and universal-joint axles combined with off-the-shelf bearings. Steering is controlled via an off-the-shelf servo, with a brushless motor putting power down to all four wheels. While drifting at full scale is best achieved with rear-wheel-drive, it’s easier to control at the small scale with four driven wheels.

True to the DIY ethos, an Arduino-based RC system is used to drive the steering servo and motor speed controller, with a home-built pistol-grip controller. It also activates a small power supply which runs little humidifier modules, which turn water into a visible vapor for a fun smoke effect. It doesn’t really imitate tire smoke, since it disappears nearly the instant the car moves, but it’s still a neat effect.

It’s a neat build that makes a great starting point for your dive into RC. Meanwhile, if you’re more about speed than getting sideways, we’ve seen a homebrew RC car designed to that end as well. Video after the break. Continue reading “3D-Printed RC Drift Car Comes With Smoke Effects” →

The Perfect Desktop Kit For Experimenting With Self Driving Cars

May 14, 2024 by 1 Comment

When we think about self-driving cars, we normally think about big projects measured in billions of dollars, all funded by major automakers. But you can still dive into this world on a smaller scale, as [jmoreno555] demonstrates.

The build consists of a small RC car—an HSP 94123, in fact. It’s got a simple brushed motor inside, driven by a conventional speed controller, and servo-driven steering. A Raspberry Pi 4 is charged with driving the car, but it’s not alone. It’s outfitted with a Google Coral USB stick, which is a machine learning accelerator card capable of 4 trillion operations per second. The car also has a Wemos D1 onboard, charged with interfacing distance sensors to give the car a sense of its environment. Vision is courtesy of a 1.2-megapixel camera with a 160-degree lens, and a stereoscopic camera with twin 75-degree lenses. Software-wise, it’s early days yet. [jmoreno555] is exploring the use of Python and OpenCV to implement basic lane detection and other self driving routines, while using Blender as a simulator.

The real magic idea, though, is the treadmill. [jmoreno555] realized that one of the frustrations of working in this space is in having to chase a car around a test track. Instead, the use of a desktop treadmill allows the car to be programmed and debugged with less fuss in the early stages of development.

If you’re looking for a platform to experiment with AI and self-driving, this could be an project to dive in to. We’ve covered some other great builds in this space, too. Meanwhile, if you’ve cracked driving autonomy and want to let us know, our tipsline is always standing by!

Phenolic board from an RC car - a well-known sight for a hacker

Pairing A New Remote To A Cheap RC Car

March 8, 2024 by 10 Comments

The cheap little RC cars are abundant anywhere you are, and if you’ve ever disassembled one, you are familiar with how the PCB looks. A single-sided phenolic paper PCB with a mystery chip driving a bunch of through-hole transistors, a sprinkle of through-hole capacitors, and a few supporting components for the wire antenna. It might not feel reusable, but [Chris Jones] begs to differ, with a Twitter thread showing us how he’s paired a scrap board from one RC car with a remote control from another, all to help a little family project.

These mystery ICs turn out to be RC-car-on-a-chip modules, and Chris lucked out in that his IC has a detailed datasheet available, complete with code pulse examples for different commands. The datasheet for the chip in the remote control is nowhere to be found, though, so we have to dig deeper. How about scoping the RF output? Turns out the supported codes between the two ICs are basically identical! The scrap board wouldn’t move any motors though, so it was time to narrow down the issue.

The RC car board has a 128KHz oscillator, and scoping that has shown the issue – it was producing 217KHz for some reason. It turned out that the oscillator’s load resistor was 100 kiloohms instead of recommended 200k, and switching that put it back on course. We would assume that, wherever the original remote control for that car is, it is similarly mis-tuned, or otherwise the RC car could never have worked.

Through sheer luck and tactical application of an oscilloscope, the RC car moves again, paired to a remote it was never meant to be, and the family project moves forward. Got a RC car, but no remote? Perhaps a HackRF can help.

3D Printed RC Car Is Geared For Speed

September 13, 2023 by 7 Comments

You can always go out and buy an RC car off the shelf. However, it’s readily achievable to print your own design that has many of the features of off-the-shelf models, as demonstrated by [Jinan].

[Jinan] set about creating a rear-wheel-drive design with a low center of gravity for good handling. Two large 5.2 Ah batteries slung low in the chassis help keep the car planted when cornering. [Jinan] also developed a double-wishbone suspension setup up front to handle bumps with ease.

With his eyes on top speed, [Jinan] needed a drivetrain that could handle sustained high RPM operation without failure. During the development process, [Jinan] spent plenty of time learning about the mathematics behind gear shapes before relying on a built-in CAD generator to do the job for him. Armed with proper gearing, he focused on making sure the driveshafts and other links wouldn’t fail at speed.

[Jinan] doesn’t shy away from diving into the engineering of his design, analyzing failures and improving on his designs along the way. It’s no surprise his design was able to reach 66 km/h (41 MPH) after his rigorous development process.  It’s compelling watching, and a great way to learn something.

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3D Printing RC Car Tires To Go Fast

August 30, 2023 by 15 Comments

There’s a bit of a high-speed arms race in the RC world on YouTube these days. [Michael Rectin] is in on the action, and he’s been exploring how to 3D print a decent set of tires to help his RC car reach higher speeds mph.

His first efforts involved experiments with TPU. The tires looked okay, but had very little traction. He later moved on to VarioShore TPU, a filament capable of delivering various properties depending on the printing method. Printing for the softest, and thus grippiest, possible tires, [Michael] whipped up some sporty looking boots for his wheels.

His tires improved over  off-road RC tires in one major way. His design didn’t suffer significant ballooning as the rotational velocity increased. However, the VarioShore material lacked grip compared to off-the-shelf rubber RC tires designed for high-speed use. The commercially-available tires also offered a smoother ride.

[Michael] also demonstrated some neat tricks for high-speed RC driving. He used a modified flight controller to correct the car’s steering in response to perturbations, and put in a scaling method that reduces steering inputs at higher speed. That didn’t entirely stop the carnage though, with some incidents seeing wheels thrown off in big tumbling crashes.

Electric-powered RC cars can go darn quick these days, but you might want to consider jet power if you want to break records. Video after the break.

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