Day: July 22, 2021

A Simple LEGO Automatic Transmission

July 22, 2021 by 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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What Kind Of GPU Are You?

July 22, 2021 by 9 Comments

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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Rover Uses Different Kind Of Tracks

July 22, 2021 by 7 Comments

Tracked robots usually require at least two wheels inside to work properly. However, [James Bruton] discovered a curious tractor design from the 1940s, the Fordson Rotaped, which only uses a single sprocket wheel inside each track. Being [James], he built a self-balancing robot around the rotaped concept.

Instead of a lot of short track sections, the Rotaped uses six long sections of track, about the same length as the wheel’s diameter. To keep the track on the wheel, a series of chains or an oval frame is used on the inside of the track.

As is usual for [James]’ projects, most of the mechanical parts are 3D printed. To hold the tracks in place, he stretches a bungee cord loop around three points on each side of the track. To make things more interesting, he made the robot balanced on the tracks. This took a bit of PID tuning to get working without oscillations, since the wheels experience a slight cogging effect inside the tracks. The wheels are driven by a pair of brushless motors with O-Drive controllers. The balancing is handled by an Arduino Mega, which reads processed position values from an Arduino Pro Mini connected to an MPU6050 IMU.

This might be a viable alternative to conventional tracks for certain applications, and the reduced part count is certainly an advantage. Let us know in the comments if it spawns any ideas. [James] has previously built another tracked rover, which uses flexible 3D printed track sections. By far, the biggest 3D printed tracked vehicle we’ve seen was [Ivan Miranda]’s ridable tank.

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Detecting Ripeness In Fruit And Vegetables Via Neural Networks

July 22, 2021 by 11 Comments

Humans have an innate knack for identifying food that is fit to eat. There’s a reason you instinctively enjoy fresh fruit and vegetables, but find maggot-infested rotting flesh offputting, for example. However, we like to automate as much of the food production process as possible so we can do other things, so it’s necessary to have machines sort the ripe and ready produce from the rest at times. [kutluhan_aktar] has found a way to do just that, using the power of neural networks.

The project’s goal is a straightforward one, aiming to detect ripeness in fruit and vegetables by monitoring pigment changes. Rather than use a camera, the project relies on data from an AS7341 visible light sensor, which is better suited to capturing accurate spectral data. This allows a better read of the actual light reflected by the fruit, as determined by the pigments in the skin which are directly related to ripeness.

Sample readings were taken from a series of fruit and vegetables over a period of several days, which allowed a database to be built up of the produce at various stages of ripeness. This was then used to create a TensorFlow model which can determine the ripeness of fruit held under the sensor with a reasonable degree of certainty.

The build is a great example of the use of advanced sensing in combination with neural networks. We suspect the results are far more accurate than could have reasonably be determined with a cheap webcam, though we’d love to see an in-depth comparison as such.

Believe it or not, it’s not the only fruit spectrometer we’ve featured in these hallowed pages. Video after the break.

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New Video Series: Designing With Complex Geometry

July 22, 2021 by 17 Comments

Whether it’s a 3D printed robot chassis or a stained glass window, looking at a completed object and trying to understand how it was designed and put together can be intimidating. But upon closer examination, you can often identify the repeating shapes and substructures that were combined to create the final piece. Soon you might find that the design that seemed incredibly intricate when taken as a whole is actually an amalgamation of simple geometric elements.

This skill, the ability to see an object for its principle components, is just as important for designing new objects as it is for understanding existing ones. As James McBennett explains in his HackadayU course Designing with Complex Geometry, if you want to master computer-aided design (CAD) and start creating your own intricate designs, you’d do well to start with a toolbox of relatively straightforward geometric primitives that you can quickly modify and reuse. With time, your bag of tricks will be overflowing with parametric structures that can be reshaped on the fly to fit into whatever you’re currently working on.

His tool of choice is Grasshopper, a visual programming language that’s part of Rhino. Designs are created using an interface reminiscent of Node-RED or even GNU Radio, with each interconnected block representing a primitive shape or function that can be configured through static variables, interactive sliders, conditional operations, and even mathematical expressions. By linking these modules together complex structures can be generated and manipulated programmatically, greatly reducing the time and effort required compared to a manual approach.

As with many powerful tools, there’s certainly a learning curve for Grasshopper. But over the course of this five part series, James does a great job of breaking things down into easily digestible pieces that build onto each other. By the final class you’ll be dealing with physics and pushing your designs into the third dimension, producing elaborate designs with almost biological qualities.

Of course, Rhino isn’t for everyone. The $995 program is closed source and officially only runs on Windows and Mac OS. But the modular design concepts that James introduces, as well as the technique of looking at large complex objects as a collection of substructures, can be applied to other parametric CAD packages such as FreeCAD and OpenSCAD.

Designing with Complex Geometry is just one of the incredible courses offered through HackadayU, our pay-as-you-wish grad school for hardware hackers. From drones to quantum computing, the current list of courses has something for everyone.

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Who Flew Across The Atlantic First? The Airborne Boats Of 1919

July 22, 2021 by 47 Comments

Aviation history is a bit strange. People tend to remember some firsts but not others and — sometimes — not even firsts. For example, everyone knows Amelia Earhart attempted to be the first woman to fly around the globe. She failed, but do you know who succeeded? It was Jerrie Mock. How about the first person to do it? Wiley Post, a name largely forgotten by the public. Charles Lindbergh is another great example. He was the first person to fly across the Atlantic, right? Not exactly. The story of the real first transatlantic flight is one of aviation hacking by the United States Navy.

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No Mask Required: Bring-A-Hack Is Back August 5th

July 22, 2021 by 9 Comments

Yes, we’re still in a pandemic and yes, these types of events are still happening over videoconference and not in meat space. But you know what? That means that so many more people have the opportunity to show up and show off their hacks! As long as 1 PM PDT is within your personal uptime, that is. Maybe you can make an exception if not?

Here is your link: the summer edition of Bring a Hack with Tindie and Hackaday will take place on Thursday, August 5th at 1:00 PM Pacific Daylight time (that’s 4pm EDT | 9pm BST/CET). Choose your gnarliest hack of late and go register for the event, which will be held on the Crowdcast video chat platform this time around.

The remote Bring-A-Hack held way back in April was packed with awesome people. Now is your chance to join in! You all have awesome projects from the last few months (we’ve seen a lot of them on these very pages), so come show them off to the hacker elite from around the globe. You know the deal: it really doesn’t matter what level your project is on, so don’t worry about that. As long as you’re passionate about it, we’d love to see it and hear all about the problems you had to overcome and yes, even the mistakes you made. You never know what knowledge you might have that can push someone else’s project over the finish line.

Shine up your hacks, and mark those calendars; here’s a timezone converter if you need it. Reserve your spot now. Seriously, don’t fool yourself into thinking your build isn’t impressive enough — we want to see it. My hack might not even involve a circuit, and that’s enough to pique your interest, right? See you there!