Vibratory Rock Tumbler Bounces On Printed Spring

If you’re reading Hackaday, there’s a good chance you had a rock tumbler in your younger days. Hell, we’d put odds on a few of you having one rumbling away in the background as you read this. They’re relatively simple contraptions, and a common enough DIY project. But even still, this largely 3D printed rock tumbler from [Fraens] is unique enough to stand out.

To make a basic rock tumbler, all you really need to do is rotate a cylindrical chamber and let physics do its thing. Such contraptions are known as, unsurprisingly, rotary rock tumblers. But what [Fraens] has put together here is a vibratory tumbler, which…well, it vibrates. If this was Rockaday we might go farther down this particular rabbit hole and explain the pros and cons of each machine, but the short version is that vibratory tumblers are more mechanically complex and are generally better suited to fine finish work than rotary tumblers which take a brute force approach that tends to round off the rocks.

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3D Navigator For Blender

If you work with high-end CAD workstations, you may have encountered a SpaceMouse or similar devices. Sort of a mouse with an extra dimension, they aren’t cheap. So [meisterodin1981] decided to build a do-it-yourself version for use with Blender. You can check it out in the video below.

The device uses an MPU6050 accelerometer and a spring. It also has some buttons for special features. The device uses a Teensy 2, although any controller that can provide an HID device could probably do the job. Of course, a nice 3D printed case is part of the design. A printed pair of plates holds a 3D printer bed spring to provide the device’s Z-axis movement. The wires to the encoder are routed through the center of the spring, so neatness counts.

We’ve seen other 3D mice like the Orbion. Your other option is to pick up the old-fashioned serial port versions and convert them. Until you can do your designs in virtual reality, these mice are just the ticket.

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Ultimate Power: Lithium-Ion Batteries In Series

At some point, the 3.6 V of a single lithium ion battery just won’t do, and you’ll absolutely want to stack LiIon cells in series. When you need high power, you’ve either got to increase voltage or current, and currents above say 10 A require significantly beefed up components. This is how you’re able to charge your laptop from your USB-C powerbank, for instance.

Or maybe you just need higher voltages, and don’t feel like using a step-up converter, which brings along with it some level of inefficiency. Whatever your reasons, it’s time to put some cells into series. Continue reading “Ultimate Power: Lithium-Ion Batteries In Series”

How Much Thrust Is Your Prop Really Making?

The problem of components not conforming to their claimed specification is one that must challenge engineers in all fields, including it seems, that of multi-rotors and remote controlled aircraft. A motor can boast an impressive spec on the website which sells it, but overheat or just not deliver when it’s on your bench. Thus [Valkyrie Workshop] has come up with a simple but ingenious rig to evaluate a motor and propeller combo without breaking the bank.

It tales the form of a L-shaped wooden bracket clamped to a pivot point at its corner with one arm pointing upwards, with motor and propeller in a 3D printed holder on the upwards arm. The other arm extends horizontally and lies on a digital kitchen scale the same distance from the pivot as the motor. The same force as is exerted by the motor is transmitted via the bracket to the kitchen scale, allowing a direct readout of the thrust in grams or kilograms. This is a first version of the rig, further work will move to a load cell and Arduino for more flexibility in measurement.

We’ve featured similar devices here in the past, including one version which can be mounted to an automobile so it can be tested at speed.

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Reduction of a physical map to a graph.

Where Graph Theory Meets The Road: The Algorithms Behind Route Planning

Back in the hazy olden days of the pre-2000s, navigating between two locations generally required someone to whip out a paper map and painstakingly figure out the most optimal route between those depending on the chosen methods of transport. For today’s generations no such contrivances are required, with technology having obliterated even the a need to splurge good money on a GPS navigation device and annual map updates.

These days, you get out a computing device, open Google Maps or equivalent, ask it how you should travel somewhere, and most of the time the provided route will be the correct one, including the fine details such as train platform and departure times. Yet how does all of this seemingly magical route planning technology work? It’s often assumed that Dijkstra’s algorithm, or the A* graph traversal algorithm is used, but the reality is that although these pure graph theory algorithms are decidedly influential, they cannot be applied verbatim to the reality of graph traversal between destinations in the physical world.

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Amazon’s ‘Just Walk Out’ Shopping Is Out, Moves To Dash Carts At Its Grocery Stores

After a few years of Amazon promoting a grocery shopping experience without checkout lines and frustrating self-checkout experiences, it is now ditching its Just Walk Out technology. Conceptualized as a store where you can walk in, grab the items you need and walk out with said items automatically charged to your registered payment method, it never really caught much traction. More recently it was revealed that the technology wasn’t even as automated as portrayed, with human workers handling much of the tedium behind the scenes. This despite claims made by Amazon that it was all powered by deep machine learning and generative AI.

An Amazon Dash Cart's user interface, with scanner and display. (Credit: Amazon)
An Amazon Dash Cart’s user interface, with scanner and display. (Credit: Amazon)

Instead of plastering the ceilings of stores full with cameras, it seems that Amazon instead wishes to focus on smart shopping carts that can keep track of what has been put inside them. These so-called Dash Carts are equipped with cameras and other sensors to scan barcodes on items, as well as weigh unlabeled items (like fruit), making them into somewhat of a merging of scales at the vegetable and fruit section of stores today, and the scanning tools offered at some grocery stores to help with self-checkout.

As the main problem with the Just Walk Out technology was that it required constant (700 out of 1,000 sales in 2022) human interaction, it will be interesting to see whether the return to a more traditional self-service and self-checkout model (albeit with special Dash Lanes) may speed things along. Even so, as Gizmodo notes, Amazon will still keep the Just Walk Out technology running across locations in the UK and elsewhere. Either this means the tech isn’t fully dead yet, or we will see a revival at some point in time.

The printer's display with the exploit-loaded animation playing, saying "hacked by blasty" and a bunch more stuff

A Fun Exploit For Canon Printers Brings GDB Gifts

Modern printers make it all that much more tempting to try and hack them — the hardware generally tends to be decent, but the firmware appears to be designed to squeeze as much money out of you as possible while keeping your annoyance level consistently high. That’s why it’s nice to see this exploit of the Canon imageCLASS MF74XCdw series (MF742Cdw/MF743Cdw) by [blasty], triggerable over a network connection, with a story for our amusement.

In this post, we get a tale of how this hack came out of a Pwn2Own Toronto challenge, notes on the hardware involved, and we’re shown the journey to a successful hack. The Canon printer OS is built without many of the protections, which makes playing with it easier than with more modernized targets, but it’s nevertheless not straightforward. Still, exploiting a couple things like the SOAP XML implementation and the UTF8 encoder nets you an ability to play nice animations on the display, and most certainly, control over the entirety of the hardware if you wanted it.

One of the most fun things about this hack is the GDB stub recently included in the repo. If you wanted to debug Canon printers for fun or profit, [blasty] brings you a GDB stub to do that comfortably, with a respectable README that even has porting notes for other Canon ImageCLASS printer models, should you lay your hands on a different machine of despair. WiFi connectivity appears to be enough for this hack, so you better make sure you don’t have your network-connected printers exposed on the Internet — not that you needed more reasons to avoid that.