The shredder after being rebuilt, on the bench top, with the washing machine pulley driving it spinning. It has not yet been fed, but that's about to happen.

Shredder Rebuilt From The Ashes, Aims To Produce More Ashes

April 8, 2022 by Arya Voronova 16 Comments

What do you do when you buy a broken shredder and, upon disassembly, find its gears in pieces? You might reach towards your 3D printer – this one’s not that kind of shredder, however. [New Yorkshire Workshop] gives us a master class on reviving equipment and putting it to good use – this one’s assigned to help turn their cardboard stores into briquettes for their wood burner.

But first, of course, it had to be fixed – and fixed it was, the crucial parts re-designed and re-built around a sturdy wooden frame. It was made into a machine built to last; an effort not unlikely to have been fueled with frustration after seeing just how easily the stock gears disintegrated. The stock gear-based transmission was replaced with a sprocket and chain mechanism, the motor was wired through a speed controller, and a washing machine pulley was used to transfer power from the motor to the freshly cleaned and re-oiled shredder mechanism itself. This shredder lost its shell along the way, just like a crab does as it expands – and this machine grew in size enough to become a sizeable benchtop appliance.

After cutting loads of cardboard into shredder-fitting pieces, they show us the end result – unparalleled cardboard shredding power, producing bags upon bags of thinly sliced cardboard ready to be turned into fuel, making the workshop a bit warmer to work in. The video flows well and is a sight to see – it’s a pleasure to observe someone who knows their way around the shop like folks over at [New Yorkshire Workshop] do, and you get a lot of insights into the process and all the little tricks that they have up their sleeves.

The endgoal is not reached – yet. The shredder’s output is not quite suitable for their briquette press, a whole project by itself, and we are sure to see the continuation of this story in their next videos – a hydraulic briquette press was suggested as one of the possible ways to move from here, and their last video works on exactly that. Nevertheless, this one’s a beast of a shredder. After seeing this one, if you suddenly have a hunger for powerful shredders, check this 3D printed one out.

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Tracked RC Vehicle Is (Mostly) 3D Printed

March 17, 2022 by Bryan Cockfield 2 Comments

While wheels might seem like a foundational technology, they do have one major flaw: they typically need maintained roads in order to work. Anyone who has experience driving a Jeep or truck off-road likely knows this first-hand. For those with extreme off-road needs the track is often employed. [Let’s Print] is working on perfecting his RC tracked vehicle to take advantage of these perks using little more than 3D printed parts and aluminum stock.

This vehicle doesn’t just include the 3D printed tracks, but an entire 3D printed gearbox and drivetrain to drive them. Each track is driven by its own DC motor coupled to a planetary gearbox to give each plenty of torque to operate in snow or mud. The gearbox is mated to a differential which currently shares a shaft, which means that steering is currently not possible. The original plan was to have each motor drive the tracks independently but a small mistake in the build meant that the shaft needed to be tied together. [Let’s Print] has several options to eventually include steering, including an articulating body or redesigning the drivetrain to be able to separate the shaft.

While this vehicle currently has no wheels in order to improve traction, [Let’s Print] does point out that a pair of wheels could complement this vehicle when he finished the back half of it since wheels have a major advantage over tracks when it comes to steering. A vehicle with both could have the advantages of both, so we’re interested to see where this build eventually goes.

Thanks to [Joonas] for the tip!

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Autonomous Mower Hits Snag

February 28, 2022 by Bryan Cockfield 10 Comments

Interfacing technology and electronics with the real world is often fairly tricky. Complexity and edge cases work their way in to every corner of a project like this; just ask anyone who has ever tried to operate a rover on Mars, make a hydroponics garden, or build almost any robotics project. Even those of us who simply own a consumer-grade printer are flummoxed by the ways in which they can fail when manipulating single sheets of paper. This robotic lawnmower is no exception, driving its creator [TK] to extremes to get it to mow his lawn.

[TK] actually had a platform for his autonomous mower ready to go thanks to a previous build using this solar-powered robot to explore the Australian outback. Adding another motor to handle the grass trimming seemed simple at first and he set about wiring it all up and interfacing it to the robot. After the first iteration he found the robot was moving too fast to effectively cut the grass, so he added a more powerful cutting motor and a gearbox to help the mower crawl more slowly over the lawn. Disaster struck when his 3D printed mount for the steel cutting blades shattered, but with [TK] uninjured he pushed on with more improvements.

As it stands right now, the mower can effectively cut the grass moving forward even with the plastic-only cutting blades that [TK] is using now for safety reasons. The mower stripped its reverse gear so there still are some improvements to make before this robot is autonomously cutting the lawn without supervision. Normally we see lawnmowers retrofitted with robotics rather than robotics retrofitted with a lawnmower, but we’re excited to see any approach that lets us worry about one less household chore.

Thanks to [Rob] for the tip!

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Resin-Printed Gears Versus PLA: Which Is Tougher?

February 10, 2022 by Lewin Day 33 Comments

When it comes to making gearboxes, 3D printing has the benefit that it lets you whip up whatever strange gears you might need without a whole lot of hunting around at obscure gear suppliers. This is particularly good for those outside the limited radius served by McMaster Carr. When it came to 3D printed gears though, [Michael Rechtin] wondered whether PLA or resin-printed gears performed better, and decided to investigate.

The subject of the test is a 3D-printed compound planetary gearbox, designed for a NEMA-17 motor with an 80:1 reduction. The FDM printer was a Creality CR10S, while the Creality LD02-H was on resin duty.

The assembled gearboxes were tested by using a 100 mm arm to press against a 20 kg load cell so that their performance could be measured accurately. By multiplying the force applied to the load cell by the length of the arm, the torque output from the gearbox can be calculated. A rig was set up with each gearbox pushing on the load cell in turn, with a closed-loop controller ensuring the gearbox is loaded up to the stall torque of the stepper motor before letting the other motor take over.

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Keynote Video: Jeremy Fielding Wants To Help You Get Moving

December 23, 2021 by Tom Nardi 7 Comments

For many DIY hardware projects, the most movement it’s likely to see is when we pick the assembled unit up off the workbench and carry it to wherever it’s destined to spend the rest of its functional life. From weather sensors to smart mirrors, there’s a huge array of devices that don’t need to move one millimeter to function. But eventually, you’re likely to run into a project that’s a bit more dynamic. Maybe you’d like to motorize your window shades, or go all out and build a remote controlled rover. With these more active designs comes a whole slew of new problems you may never have encountered before.

Luckily for us, folks like Jeremy Fielding are out there and willing to share their knowledge. In his fascinating presentation for the 2021 Hackaday Remoticon, Building Hardware that Moves: the Fundamentals that Everyone Should Know, he took viewers on a whirlwind tour of what he’s learned about designing and building complex machines from his years of professional experience. Whether its a relatively simple articulated workbench for the shop, a gargantuan earthmoving machine, or a high-dexterity robotic arm, each project he’s worked on has presented unique challenges that needed to be solved.

Not all of Jeremy’s machines will fit in your average workshop.

A lot of the projects that Jeremy has worked on are on a much larger scale than what your average hobbyist is ever going to run into. When there’s an arrow pointing out the tiny human in a picture of you and the machine you’re currently working on, you know things are getting serious. But as anyone who’s watched his YouTube videos knows, he’s got a real knack for taking these high-level concepts and distilling them into something more digestible for the home gamer.

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Cheap Big Servo For Robot Arm

November 19, 2021 by Lewin Day 10 Comments

[Skyentific] is looking to push the hobbyist robotics state of the art. Motors and their gears, the actuators, are typically the most expensive part. For his build, he realised he needed big servos capable of delivering plenty of torque. Thus, he set about creating a 3D-printed design to get the job done on a budget. (Video, embedded below.)

Stepper motors are the order of the day here, chosen for their low cost compared to brushless solutions, particularly when taking control hardware into account. In this design, the stepper motor drives a sun gear as part of a bigger planetary gearbox with a high gear ratio. Cross-roller bearings are used to allow the servo to effectively handle both radial and axial loads. The servo as a whole is designed to fit neatly into the joints of the robot arm itself, and has external mounting points provisioned as such.

It’s a neat servo that somewhat apes those used on full-sized industrial designs, at least in the sense of being an integrated part of the joints of a robot arm. It also comes in at a relatively-cheap $32 based on the materials used by [Skyentific].

We’ve seen some related work from [Skyentific] before, too – like this interesting cable-driven joint. Video after the break.

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A Simple LEGO Automatic Transmission

July 22, 2021 by Lewin Day 9 Comments

The automatic transmission in your average automobile can be a complicated, hydraulic-y thing full of spooky fluids and many spinning parts. However, simpler designs for “automatic” gearboxes exist, like this Lego design from [FUNTastyX].

The build is based around a simple open differential but configured in a unique way. A motor drives what would typically be one of the output shafts as an input. The same motor is also geared what would normally be the main differential input shaft as well. In these conditions, this double-drive arrangement would sum the speed input and lead to a faster rotational speed at the other shaft, which becomes the output.

However, the trick in this build is that the drive going to what would be the usual differential input is done through a Lego slipper clutch. This part, as explained by [TechnicBricks], allows the outer teeth of the gear to slip relative to the shaft once torque demand is exceeded. What this functionally does is that when the output of the “automatic gearbox” is loaded down, the extra torque demand causes the clutch to slip. This then leads to only one input to the differential doing any work, changing the gear ratio automatically.

It’s likely not a particularly efficient gearbox, as there are significant losses through the very simple clutch, we suspect. However, it does technically work, and we’d love to see its performance rated directly against other simple Lego gearbox designs.

It’s a little confusing to explain in text, but the video from [FUNTastyX] does a great job at explaining the principle in just a few minutes. We’ve seen plenty of crazy Lego gearboxes over the years, and we doubt this will be the last. Video after the break.

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