Hoverboard Turned Heavy Duty Remote Control Rover

May 3, 2021 by Tom Nardi 20 Comments

They might not be the hoverboards we were promised in Back to the Future II, but the popular electric scooters that have commandeered the name are exciting pieces of tech in their own way. Not because we’re looking to make a fool of ourselves by actually riding one, but because they’re packed full of useful hardware that’s available for dirt cheap thanks to the economies of scale and the second-hand market.

In his latest video, the ever resourceful [MakerMan] turns a pair of hoverboards into a capable remote controlled mobile platform perfect for…well, whatever you want to move around. Its welded steel construction is certainly up for some heavy duty tasks, and while we can’t say we’d ever tow a SUV with it as shown in the video below, it’s nice to know we’d have the option.

The project starts by liberating the four wheel motors from the scooters and carefully cutting down the frame to preserve the mounting hardware. These mounts are ultimately welded to the frame of the rover, with a piece of diamond plate screwed down on top. On the bottom, [MakerMan] mounts the two control boards and a custom fabricated 36 V battery pack.

He doesn’t go into any detail on how he’s interfacing the RC hardware with the motor controllers, but as we’ve seen with past hacks, there’s open source firmware replacements for these boards that allow them to be controlled by external inputs. Presumably something similar is being used here, but we’d be interested to hear otherwise. Of course you could swap the RC hardware out for a microcontroller or Raspberry Pi if you were looking to make some kind of autonomous rover.

Don’t have a welder or convenient collection of scrap steel laying around? No worries. Prolific tinkerer [Aaron Christophel] put something very similar together using bolted aluminum extrusion.

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Hackaday Links: May 2, 2021

May 2, 2021 by Dan Maloney 3 Comments

Mars is getting to be a busy place, what with helicopters buzzing around and rovers roving all about the place. Now it’s set to get a bit more crowded, with the planned descent of the newly-named Chinese Zhurong rover. Named after the god of fire from ancient Chinese mythology, the rover, which looks a little like Opportunity and Spirit and rides to the surface aboard something looking a little like the Viking lander, will carry a suite of scientific instruments around Utopia Planitia after it lands sometime this month. Details are vague; China usually plays its cards close to the vest, and generally makes announcements only when a mission is a fait accompli. But it appears the lander will leave its parking orbit, which it entered back in February, sometime this month. It’s not an easy ride, and we wish Zhurong well.

Speaking of space, satellites don’t exactly grow on trees — until they do. A few groups, including a collaboration between UPM Plywood and Finnish startup Arctic Astronautics, have announced intentions to launch nanosatellites made primarily of wood. Japanese logging company Sumitomo Forestry and Kyoto University also announced their partnership, formed with the intention to prove that wooden satellites can work. While it doesn’t exactly spring to mind as a space-age material, wood does offer certain advantages, including relative transparency to a wide range of the RF spectrum. This could potentially lead to sleeker satellite designs, since antennae and sensors could be located inside the hull. Wood also poses less of a hazard than a metal spaceframe does when the spacecraft re-enters the atmosphere. But there’s one serious disadvantage that we can see: given the soaring prices for lumber, at least here in the United States, it may soon be cheaper to build satellites out of solid titanium than wood.

If the name Ian Davis doesn’t ring a bell with you, one look at his amazing mechanical prosthetic hand will remind you that we’ve been following his work for a while now. Ian suffered a traumatic amputation of the fingers of his left hand, leaving only his thumb and palm intact, and when his insurance wouldn’t pay for a prosthetic hand, he made his own. Ian has gone through several generations, each of which is completely mechanical and controlled only by wrist movements. The hands are truly works of mechanical genius, and Ian is now sharing what he’s learned to help out fellow hand-builders. Even if you’re not building a hand, the video is well worth watching; the intricacy of the whiffle-tree mechanism used to move the fingers is just a joy to behold, and the complexity of movement that Ian’s hand is capable of is just breathtaking.

If mechanical hands don’t spark your interest, then perhaps the engineering behind top fuel dragsters will get you going. We’ll admit that most motorsports bore us to tears, even with the benefit of in-car cameras. But there’s just something about drag cars that’s so exciting. The linked video is a great dive into the details of the sport, where engines that have to be rebuilt after just a few seconds use, fuel flows are so high that fuel lines the size of a firehouse are used, and the thrust from the engine’s exhaust actually contributes to the car’s speed. There’s plenty of slo-mo footage in the video, including great shots of what happens to the rear tires when the engine revs up. Click through the break for more!

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Putting Perseverance Rover’s View Into Satellite View Context

March 30, 2021 by Roger Cheng 3 Comments

It’s always fun to look over aerial and satellite maps of places we know, seeing a perspective different from our usual ground level view. We lose that context when it’s a place we don’t know by heart. Such as, say, Mars. So [Matthew Earl] sought to give Perseverance rover’s landing video some context by projecting onto orbital imagery from ESA’s Mars Express. The resulting video (embedded below the break) is a fun watch alongside the technical writeup Reprojecting the Perseverance landing footage onto satellite imagery.

Some telemetry of rover position and orientation were transmitted live during the landing process, with the rest recorded and downloaded later. Surprisingly, none of that information was used for this project, which was based entirely on video pixels. This makes the results even more impressive and the techniques more widely applicable to other projects. The foundational piece is SIFT (Scale Invariant Feature Transform), which is one of many tools in the OpenCV toolbox. SIFT found correlations between Perseverance’s video frames and Mars Express orbital image, feeding into a processing pipeline written in Python for results rendered in Blender.

While many elements of this project sound enticing for applications in robot vision, there are a few challenges touched upon in the “Final Touches” section of the writeup. The falling heatshield interfered with automated tracking, implying this process will need help to properly understand dynamically changing environments. Furthermore, it does not seem to run fast enough for a robot’s real-time needs. But at first glance, these problems are not fundamental. They merely await some motivated people to tackle in the future.

This process bears some superficial similarities to projection mapping, which is a category of projects we’ve featured on these pages. Except everything is reversed (camera instead of video projector, etc.) making the math an entirely different can of worms. But if projection mapping sounds more to your interest, here is a starting point.

[via Dr. Tanya Harrison @TanyaOfMars]

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A Technical (But Not Too Technical) Explanation Of Landing Perseverance Rover On Mars

March 19, 2021 by Roger Cheng 6 Comments

There was a lot of enthusiasm surrounding Mars arrival of Perseverance rover, our latest robotic interplanetary explorer. Eager to capitalize on this excitement, NASA JPL released a lot of information to satisfy curiosity of the general public. But making that material widely accessible also meant leaving out many technical details. People who crave just a little more can head over to How NASA’s Perseverance Landed On Mars: An Aerospace Engineer Breaks It Down In Fascinating Detail published by Jalopnik.

NASA JPL’s public materials mostly explained the mission in general terms. Even parts with scientific detail were largely constrained for a target audience of students K-12. Anyone craving more details can certainly find them online, but they would quickly find themselves mired in highly technical papers written by aerospace engineers and planetary geologists for their peers. There is a gap in between those extremes, and this write-up slots neatly in that gap. Author [Brian Kirby] is our helpful aerospace engineer who compiled many technical references into a single narrative of the landing, explained at a level roughly equivalent to undergraduate level math and science courses.

We get more details on why the target landing site is both geologically interesting and technically treacherous, requiring development of new landing smarts that will undoubtedly help future explorers both robotic and human. The complex multi-step transition from orbit to surface is explained in terms of managing kinetic energy. Condensing a wide range of problems to a list of numbers that helps us understand why, for example, a parachute was necessary yet not enough to take a rover all the way to the surface.

Much of this information is known to longtime enthusiasts, but we all had to get our start somewhere. This is a good on-ramp for a new generation of space fans, and together we look forward to Perseverance running down its long and exciting to-do list. Including flying a helicopter, packing up surface samples of Mars, and seeing if we can extract usable oxygen from Martian atmosphere.

A New Open-Source Farming Robot Takes Shape

March 5, 2021 by Jenny List 48 Comments

The world of automated farming may be an unglamorous one to those not invested in its attractions, but like the robots themselves that quietly get on in the background with tending crops, those who follow that path spend many seasons refining their designs. The Acorn is a newly-open-sourced robot from Twisted Fields, a Californian research farm, and it provides a fascinating look at the progress of a farming robot design from germination onwards.

The Acorn is not a CNC gantry for small intensive gardens in the manner of designs such as the Farmbot, instead it’s an autonomous solar-powered rover intended for larger farms which will cruise the fields continuously tending to the plants in its patch. It’s a work in progress, so what we see is the completed rover with the tools and machine vision to follow. It pursues the course of a low-cost lightweight platform, an aluminium chassis surmounted by the solar panel, with mountain bike front fork derived wheels at each corner. It has four wheel drive and four wheel steering, meaning that it can traverse the roughest of farmland. We can see its progress since a 2019 prototype, and while it seems as slow as the seasons themselves to mature, we can see that the final version could be a significantly useful machine on a small farm.

It’s not the first autonomous farming robot we’ve seen over the years, as for example this slightly more robust Australian model. We’re guessing that this is the direction autonomous farming is likely to take, with the more traditional tractor-based machinery projected by some manufacturers taking on repetitive loading and hauling roles.

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Getting Ready For Mars: The Seven Minutes Of Terror

February 8, 2021 by Dan Maloney 47 Comments

For the past seven months, NASA’s newest Mars rover has been closing in on its final destination. As Perseverance eats up the distance and heads for the point in space that Mars will occupy on February 18, 2021, the rover has been more or less idle. Tucked safely into its aeroshell, we’ve heard little from the lonely space traveler lately, except for a single audio clip of the whirring of its cooling pumps.

Its placid journey across interplanetary space stands in marked contrast to what lies just ahead of it. Like its cousin and predecessor Curiosity, Perseverance has to successfully negotiate a gauntlet of orbital and aerodynamic challenges, and do so without any human intervention. NASA mission planners call it the Seven Minutes of Terror, since the whole process will take just over 400 seconds from the time it encounters the first wisps of the Martian atmosphere to when the rover is safely on the ground within Jezero Crater.

For that to happen, and for the two-billion-dollar mission to even have a chance at fulfilling its primary objective of searching for signs of ancient Martian life, every system on the spacecraft has to operate perfectly. It’s a complicated, high-energy ballet with high stakes, so it’s worth taking a look at the Seven Minutes of Terror, and what exactly will be happening, in detail.

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Obstacle Climbing Rover Built With The Power Of Lego

January 23, 2021 by Danie Conradie 7 Comments

When we want to prototype a rover, we’ve developed a tendency to immediately reach for the 3D printer and Arduino or Raspberry Pi. It’s easy to forget the prototyping tool many of us grew up using: LEGO. The [Brick Experiment Channel] has not forgotten, and in the video after the break demonstrates how he used Lego Technic components to prototype an impressive little obstacle climbing robot.

The little Lego rover starts as a simple four-wheeled rover trying to climb on top of a book. Swap in a four-wheel-drive gearbox and grippy tires, and it clears the first obstacle. Add a few books to the stack causes the break-over angle to become an issue, so the rover gets an inverted-V chassis. As the obstacle height increases, batteries are moved around for better weight distribution, but the real improvement comes when an actuating middle joint is added, turning it into a wheeled inchworm. Clearing overhangs suspended beams, and gaps are all just a matter of finding the right technique.

Thanks to Lego’s modularity, all this is possible in an hour or two where a 3D printer and CAD might have stretched it into days. This robot does have the limitation of not being able to turn. Conventional car steering or Mecanum wheels are two options, but how would you do it?

The [Brick Experiment Channel] knows a thing or two about building Lego robots, even for stealing keys. Continue reading “Obstacle Climbing Rover Built With The Power Of Lego” →