Model Rocket Nails Vertical Landing After Three-Year Effort

July 10, 2024 by Dan Maloney 30 Comments

Model rocketry has always taken cues from what’s happening in the world of full-scale rockets, with amateur rocketeers doing their best to incorporate the technologies and methods into their creations. That’s not always an easy proposition, though, as this three-year effort to nail a SpaceX-style vertical landing aptly shows.

First of all, hats off to high schooler [Aryan Kapoor] from JRD Propulsion for his tenacity with this project. He started in 2021 with none of the basic skills needed to pull off something like this, but it seems like he quickly learned the ropes. His development program was comprehensive, with static test vehicles, a low-altitude hopper, and extensive testing of the key technology: thrust-vector control. His rocket uses two solid-propellant motors stacked on top of each other, one for ascent and one for descent and landing. They both live in a 3D printed gimbal mount with two servos that give the stack plus and minus seven degrees of thrust vectoring in two dimensions, which is controlled by a custom flight computer with a barometric altimeter and an inertial measurement unit. The landing gear is also clever, using rubber bands to absorb landing forces and syringes as dampers.

The video below shows the first successful test flight and landing. Being a low-altitude flight, everything happens very quickly, which probably made programming a challenge. It looked like the landing engine wasn’t going to fire as the rocket came down significantly off-plumb, but when it finally did light up the rocket straightened and nailed the landing. [Aryan] explains the major bump after the first touchdown as caused by the ascent engine failing to eject; the landing gear and the flight controller handled the extra landing mass with aplomb.

All in all, very nice work from [Aryan], and we’re keen to see this one progress.

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AI Kayak Controller Lets The Paddle Show The Way

June 10, 2024 by Dan Maloney 6 Comments

Controlling an e-bike is pretty straightforward. If you want to just let it rip, it’s a no-brainer — or rather, a one-thumber, as a thumb throttle is the way to go. Or, if you’re still looking for a bit of the experience of riding a bike, sensing when the pedals are turning and giving the rider a boost with the motor is a good option.

But what if your e-conveyance is more of the aquatic variety? That’s an interface design problem of a different color, as [Braden Sunwold] has discovered with his DIY e-kayak. We’ve detailed his work on this already, but for a short recap, his goal is to create an electric assist for his inflatable kayak, to give you a boost when you need it without taking away from the experience of kayaking. To that end, he used the motor and propeller from a hydrofoil to provide the needed thrust, while puzzling through the problem of building an unobtrusive yet flexible controller for the motor.

His answer is to mount an inertial measurement unit (IMU) in a waterproof container that can clamp to the kayak paddle. The controller is battery-powered and uses an nRF link to talk to a Raspberry Pi in the kayak’s waterproof electronics box. The sensor also has an LED ring light to provide feedback to the pilot. The controller is set up to support both a manual mode, which just turns on the motor and turns the kayak into a (low) power boat, and an automatic mode, which detects when the pilot is paddling and provides a little thrust in the desired direction of travel.

The video below shows the non-trivial amount of effort [Braden] and his project partner [Jordan] put into making the waterproof enclosure for the controller. The clamp is particularly interesting, especially since it has to keep the sensor properly oriented on the paddle. [Braden] is working on a machine-learning method to analyze paddle motions to discern what the pilot is doing and where the kayak goes. Once he has that model built, it should be time to hit the water and see what this thing can do. We’re eager to see the results.
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Tiny Motion Detection Alarm Does The Trick

February 24, 2024 by Kristina Panos 6 Comments

If you have mischievous children or forgetful elderly in your life, you might want to build a couple of these tiny motion detection alarms to help keep them out of harm’s way. Maybe you want to keep yourself out of the cookie jar. We say good for you.

But you could always put one of these alarms on a window, a drawer, or anything else you don’t want opened or moved. The MPU6050 3-axis IMU makes sure that any way the chosen item gets jostled, that alarm is going off.

As you may have guessed, there isn’t much more to this build — the brain is a Seeed Xiao ESP32-C3, and there’s a buzzer, a battery, a switch, and a push button to program it.

The cool thing about using an ESP32-C3 is that [gokux] can use these for other things, like performing a task when motion is detected. If you do want to build yourself a couple of these, here are step-by-step instructions.

If you’d rather detect motion in the vicinity, here’s a PIR-based solution.

Fancy Gyroscopes Are Key To Radio-Free Navigation

November 1, 2023 by Lewin Day 49 Comments

Back in the old days, finding out your location on Earth was a pretty involved endeavor. You had to look at stars, use fancy gimballed equipment to track your motion, or simply be able to track your steps really really well. Eventually, GPS would come along and make all that a bit redundant for a lot of use cases. That was all well and good, until it started getting jammed all over the place to frustrate militaries using super-accurate satellite-guided weapons.

Today, there’s a great desire for more accurate navigational methods that don’t require outside communications that can easily be jammed. High-tech gyroscopes have long been a big part of that effort, allowing the construction of inertial navigation systems with greater accuracy than ever before.

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Behold The Mega-Wheelie, A Huge One-Wheeled Electric Skateboard

October 29, 2023 by Donald Papp 8 Comments

DIY electric personal vehicles are a field where even hobbyists can meaningfully innovate, and that’s demonstrated by the Mega-Wheelie, a self-balancing one-wheeled skateboard constructed as an experiment in traversing off-road conditions.

[John Dingley] and [Nick Thatcher] have been building and testing self-balancing electric vehicles since 2008, with a beach being a common testing ground. They suspected that a larger wheel was the key to working better on rough ground and dry sand and tested this idea by creating a skateboard with a single wheel. A very big, very wide wheel, in fact.

The Mega-Wheelie houses a 24V LiFePO4 battery pack, 450 W gearmotor with chain and sprocket drive, SyRen motor controller from Dimension Engineering, Arduino microcontroller, and an inertial measurement unit to enable the self-balancing function. Steering is done by leaning, and the handheld controller is just a dead man’s switch that disables the vehicle if the person piloting it lets go.

Design-wise, a device like this has a few challenging constraints. A big wheel is essential for performance but takes up space that could otherwise be used for things like batteries. Also, the platform upon which the pilot stands needs to be as low to the ground as possible for maximum stability. Otherwise, it’s too easy to fall sideways. On the other hand, one must balance this against the need for sufficient ground clearance.

Beaches are rarely covered in perfectly smooth and firm sand, making them a good test area.

In the end, how well did it work? Well enough to warrant a future version, says [John]. We can’t wait to see what that looks like, considering their past 3000 W unicycle’s only limitation was “personal courage” and featured a slick mechanism that shifted the pilot’s weight subtly to aid steering. A video of the Mega-Wheelie (and a more recent unicycle design) is embedded just below the page break.

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An Electric Unicycle, In Minimalist Form

September 1, 2023 by Jenny List 18 Comments

When self balancing scooters hit the market a few years ago they brought alongside them a range of machines, from the hoverboard kids toys which have provided so many useful parts, to the stand-astride electric unicycles. These last machines have a bulky battery and controller box atop the wheel, and [Dycus] set his sights on this by transferring it to a backpack with the vehicle’s IMU sensor relocated to one of the pedals.

Such a job is not merely a simple case of rewiring with some longer cables, as a first challenge the IMU communicates via I2C which isn’t suitable for longer distances. This is solved by a chipset which places the I2C on a differential pair, but even then it’s not quite a case of stepping on and zipping about. The PID parameters of the balancing algorithm on a stock machine are tuned for the extra weight of the battery on top, and these needed to be modified. Fortunately there have been enough people hacking the STM microcontroller and firmware involved for this task to be achievable, but we’d rate it as still something not for the faint-hearted.

The final result can be seen in the video below, and the quality of the physical work shows as very high. The former battery box is repurposed into a stylish backpack, and though the newly minimalist foot pedals and wheel are a little less easy to get going he zips around with ease.

Hungry for more? This ain’t the first we’ve shown you.

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Hackaday Links: August 20, 2023

August 20, 2023 by Dan Maloney 14 Comments

In some ways, we’ve become a little jaded when it comes to news from Mars, which almost always has to do with the Ingenuity helicopter completing yet another successful flight. And so it was with the report of flight number 54 — almost. It turns out that the previous flight, which was conducted on July 22, suffered a glitch that cut the flight short by forcing an immediate landing. We had either completely missed that in the news, or NASA wasn’t forthcoming with the news, perhaps until they knew more. But the details of the error are interesting and appear related to a glitch that happened 46 flights before, way back in May of 2021, that involves dropped frames from the video coming from the helicopter’s down-facing navigational camera. When this first cropped up back on flight six, it was only a couple of missed frames that nearly crashed the craft, thanks to confusion between the video stream and the inertial data. Flight engineers updated the aircraft’s software to allow for a little more flexibility with dropped frames, which worked perfectly up until the aborted flight 53.

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