Hackaday Podcast 128: 3D-Printing Injection Molds, Squiggly Audio Tape, Curvy Mirrors, And Space Cadets

Hackaday editors Elliot Williams and Mike Szczys bubble sort the best hardware hacks so you don’t miss ’em. This week we’re smitten by the perfection of a telephone tape loop message announcer. We enjoyed seeing Blender’s ray tracing to design mirrors, and a webcam and computer monitor to stand in for triple-projector-based fractal fun. There’s a bit of injection molding, some Nintendo Switch disassembling, and the Internet on a calculator. We close the show with a pair of Space stories, including the happy news this week that Wally Funk finally made it there!

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

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3D Printed Roller Coaster Looks Pretty Darn Fun

Rollercoasters are great fun if you can deal with the exhilaration without throwing up or otherwise screaming until you pass out. Of course, the big outdoors ones are a little hard to get to at the moment, what with a pandemic raging outside. However, [3d_coasters] has built a tabletop design that, while it’s too small to ride, is nonetheless quite impressive. (Video, embedded below.)

The coaster is of the launch design. It relies on an elastic cord that is wound up to high tension to launch the train up to speed, with the train then coasting around the rest of the curves on the track. The quality of the modelling is highly impressive, too. The doors at the boarding platform are even actuated to simulate riders boarding the train! Everything is controlled by an Arduino, a handful of micro servos, and a DC motor.

As you might imagine, this project didn’t happen overnight. 600 hours were logged in Fusion 360 developing the track, and slicing the models in Cura for 3D printing took a further 5 hours. The actual printing process itself took 800 hours, not including finishing, so this project certainly isn’t one for the faint of heart. The final model weighs a full 30 lbs.

Believe it or not, we’ve featured 3D printed rollercoasters before, too. Video after the break.

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This Week In Security: NSO, Print Spooler, And A Mysterious Decryptor

The NSO Group has been in the news again recently, with multiple stories reporting on their Pegasus spyware product. The research and reporting spearheaded by Amnesty International is collectively known as “The Pegasus project”. This project made waves on the 18th, when multiple news outlets reported on a list of 50,000 phone numbers that are reported as “potential surveillance targets.” There are plenty of interesting people to be found on this list, like 14 heads of state and many journalists.

There are plenty of questions, too. Like what exactly is this list, and where did it come from? Amnesty international has pointed out that it is not a list of people actively being targeted. They’ve reported that of the devices associated with an entry on the list that they have been able to check, roughly 50% have shown signs of Pegasus spyware. The Guardian was part of the initial coordinated release, and has some impressive non-details to add:

The presence of a phone number in the data does not reveal whether a device was infected with Pegasus or subject to an attempted hack. However, the consortium believes the data is indicative of the potential targets NSO’s government clients identified in advance of possible surveillance attempts.

Amazon’s AWS was named as part of the C&C structure of Pegasus, and in response, they have pulled the plug on accounts linked to NSO. For their part, NSO denies the validity of the list altogether. Continue reading “This Week In Security: NSO, Print Spooler, And A Mysterious Decryptor”

LEGO Pole Climbers Are Great Study In What It Takes To Go Vertically Upwards

Climbing a pole with a robot might sound complicated and hard, but it doesn’t have to be. This video from [Brick Experiment Channel] demonstrates multiple methods of doing the job while keeping things simple from a mechanical perspective. (Video, embedded below.)

The first method uses a gravity locking design, where the weight of the battery pack is placed on a lever arm to increase the normal force on the wheels gripping the pole. Increasing the length of the lever arm, reducing the angle of the crawler, or adding grippier tyres can all be used to increase the grip with this design. The final design of this type is able to climb most of the way up an 8 meter flagpole without too much trouble.

The next version uses rubber bands to help add tension to grip the pole. This too works well and makes it to the top of the flagpole. The final build is a circulating design that looks truly wild in action, and winds its way to the top of the flagpole as well.

It’s great to see the experimental method of designing these Lego creations, as well as seeing how they do in the wild. [Brick Experiment Channel] has been featured here before, too.

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Tardygrade Walker Is A Lesson In 3D Printed Design

The ability to quickly create complex parts with 3D printers has created a platform to show off mechanical design skills. This is true in the case of [Dejan Ristic]’s capable little Tardygrade walking robot, which uses only two servos and a bunch of clever 3D printed parts.

The robot’s chassis is split into two subassemblies, each with a pair of feet on diagonal corners. As one pair of feet lifts the robot, the other section of the robot can rotate before coming back down, allowing the robot to turn. One servo handles the actuation of the feet, while the other rotates the body as required. An ESP32 based controller creates a web server user interface, and power comes from a lipo cell.

The interesting part of this robot is in how [Dejan] designed it for printing and assembly. All the parts can print without support, and in the correct orientation to optimize strength. There are only six screws in the assembly holding the servo and servo horns, while everything else uses snap fits or short pieces of filament. Take a look at the videos after the break to gain some appreciation of the design effort and attention to detail that went into this robot. Even the contact surfaces of the feet were carefully designed for optimum walking over flat surfaces and small obstacles.

This reminds us of [gzumwalt]’s little 3D printed creations, like the fridge crawler and mechanical edge-avoiding robot.

A Simple LEGO Automatic Transmission

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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What Kind Of GPU Are You?

In the old days, big computers often had some form of external array processor. The idea is you could load a bunch of numbers into the processor and then do some math operations on all of the numbers in parallel. These days, you are more likely to turn to your graphics card for number crunching support. You’ll usually use some library to help you do that, but things are always better when you understand what’s going on under the hood. That’s why we enjoyed [RasterGrid’s] post on GPU architecture types.

If you can tell the difference between IMR (immediate mode) and TBR (tile-based) rendering this might not be the post for you. But while we knew the terms, we found a lot of interesting detail including some graphics and pseudo code that clarified the key differences.

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