Rocker Bogie Suspension: The Beloved Solution To Extra-Planetary Rovers

September 14, 2023 by 18 Comments

When navigating the vast and unpredictable expanses of outer space, particularly on the alien terrains of distant planets, smart engineering often underlies every major achievement. A paramount example of this is the rocker bogie suspension system. It’s an integral component of NASA’s Mars rovers and has become an iconic feature in its own right. Its success has seen the design adopted by the Indian space program and thousands of hobbyists in turn.

So, what exactly is it that makes rocker bogie suspension such a compelling design solution? Let’s dive into the engineering that makes these six-wheeled wonders so special.

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A homebrew machine that dips a piece of wire into an etching solution

Homebrew Probe Tip Etcher Makes Amazingly Sharp Needles

September 14, 2023 by 17 Comments

There’s a simple reason why high-tech gadgets like PCs, TVs and smartphones are so cheap: they’re mass-produced. By spreading out huge engineering costs over equally huge production volumes, the cost per item can remain quite low. The flipside to this is that devices with only a small niche market can be extremely expensive even when they seem quite simple.

[Baird Bankovic], an undergrad student at Penn State University, discovered this when he was working with a scanning tunneling microscope (STM). He noticed that the machines used to make STM probes, a pretty straightforward process, cost north of $7500. This inspired him to make a cheap STM probe etching machine using simple homebrew parts.

If you’re not familiar with scanning tunneling microscopy, here’s how it works in a nutshell: a very sharp tungsten needle is positioned a few nanometers above the sample to be analyzed, and a small voltage is applied between the two. Through an effect known as quantum tunneling, a small current then flows between the probe and the sample. By observing this current and scanning the probe across the sample, a three-dimensional picture of the surface is obtained with sub-nanometer-level resolution.

One of the many factors that determine the quality of the image is the sharpness of the probe. Because a very sharp probe is extremely fragile and prone to oxidation, they are typically made on-site by dipping a piece of tungsten wire into an etchant in one of those costly machines.

That’s exactly what [Baird]’s device does: a Petri dish on a 3D printed frame holds a volume of sodium hydroxide solution, while a jackscrew Z-stage moves a probe holder up and down. A piece of tungsten wire is dipped into the solution and a voltage is applied to start the etching process. Because most of the etching happens at the liquid’s surface, the wire gets progressively thinner at that point until it snaps and the bottom half drops off. When this happens, the current through the wire changes rapidly, which triggers the machine to pull the wire out of the solution and stop the etching process.

The resulting probes have a well-defined sharp tip with an estimated width of about 50 nanometers — pretty impressive for such a simple setup. The entire hardware design is open source and available on [Baird]’s GitHub page for anyone to replicate. Nanometer-sized needles might only seem useful for those with a professional STM setup, but they also come in handy for all kinds of homebrew atomic-scale imaging experiments.

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ESP32 Drives Tiny FM Radio

September 14, 2023 by 21 Comments

Even as music streaming services and podcast apps dominate most of our listening time, it’s still a great idea to keep a radio on hand, if for nothing else than in emergency situations. After all, blizzards, hurricanes, and other natural disasters can quickly take out both home and mobile Internet access. If you’d like to have an FM radio with the absolute smallest footprint, take a look at this one built around an ESP32.

While the radio uses the ESP32 as the main control board hosted by a TTGO T-Display board which adds a 1.14 inch ST7789V IPS panel, it also makes use of the TEA5767 chip for handling the FM radio signals. As [Volos Projects] has it programmed, the ESP32 stores five preset channels which can be toggled using two buttons at the bottom of the device. There’s also some circuitry to handle output to headphones or a stereo.

For making the radio even smaller, some of the audio processing could be done on the ESP32 instead, although its much simpler to take a slightly larger footprint and offload this to an audio processing chip. Since the source code for this project is open, modifications could be done including adding seek/tune functionality instead of relying only on presets. If you’re not building this for emergencies, though, and your entire area is dominated by cookie cutter corporate-owned radio stations, an ESP32 with an internet connection is great for accessing better radio stations around the world.

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FPGA Runs IBM 5151 MDA Display

September 13, 2023 by 11 Comments

When it comes to driving a display, you can do all kinds of fancy tricks with microcontrollers to get an image up. Really, though, FPGAs are the weapon of choice for playing with these kinds of signals. [Ted Fried] put one to great work driving an ancient IBM 5151 MDA display, and shared his results on Hackaday.io.

The build relies on a Digilent Arty Z7-20 SOC FPGA development board, which has a beefy 600 MHz ARM processor on board. It also packs 500 MB of DRAM—more than enough for storing pixel data for an ancient display.

To drive the old display, [Ted] whipped up a state machine on the FPGA. It’s tasked with fetching display data from RAM and creating the appropriate timings for the MDA display interface. The images are stored directly in an array in C code running on the ARM core. From there, they are copied into the FPGA’s RAM for trucking out to the display. The 720×350 images are stored as 1 bit per pixel, and are created by converting the original JPEGs into single-bit bitmaps in GIMP, before final conversion into a C code array via utility of [Ted’s] own design.

If you’ve ever wanted to display your images in resplendent amber or green, then this could be the project for you. It’s also just a great way to learn about using FPGAs and interfacing with alternative display technologies. If you’ve been whipping up your own retro display hacks, don’t hesitate to drop us a line.

Mistranslation Of Newton’s First Law Discovered After Nearly 300 Years

September 13, 2023 by 57 Comments

For hundreds of years, we have been told what Newton’s First Law of Motion supposedly says, but recently a paper published in Philosophy of Science (preprint) by [Daniel Hoek] argues that it is based on a mistranslation of the original Latin text. As noted by [Stephanie Pappas] in Scientific American, this would seem to be a rather academic matter as Newton’s Laws of Motion have been superseded by General Relativity and other theories developed over the intervening centuries. Yet even today Newton’s theories are highly relevant, as they provide very accessible approximations for predicting phenomena on Earth.

Similarly, we owe it to scientific and historical accuracy to address such matters, all of which seem to come down to an awkward translation of Isaac Newton’s original Latin text in the 1726 third edition to English by Andrew Motte in 1729. This English translation is what ended up defining for countless generations what Newton’s Laws of Motion said, along with the other chapters in his Philosophiæ Naturalis Principia Mathematica.

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Paper Punching Machine Looks Like Cute Piece Of Computer History Past

September 13, 2023 by 23 Comments

Computing used to run on punch cards. Great stacks of cards would run middling programs, with data output onto more punched cards in turn. [Nii] has built a machine in this vein, capable of punching binary into paper tape. 

The machine is run by a stepper motor, which is charged with feeding the paper tape through the machine in steady steps. A series of vertically-actuated solenoids punch holes in the paper tape as directed. The machine buzzes and clicks away like the best electromechanical computing devices of the mid-century era.

To what end, we couldn’t possibly say. One user noted the machine was punching seemingly random binary into the paper tape, and [Nii] has not provided any explanation as to the machine’s higher purpose. Regardless, whatever it is doing, it looks like it’s doing it well. Feel free to speculate in the comments.

Impressively, the petite device will be demonstrated at MF-TOKYO, the 7th Annual Metal Forming Fair in Tokyo this year. We’re sure the clickity-clack will be muchly appreciated in person.  Video after the break.

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It’s Time You Built A Smart Pocket Watch

September 13, 2023 by 39 Comments

There’s just something about a pocket watch that screams class compared to the barbaric act of bending your arm, or the no-fun way of looking at your phone.

But smartwatches are dumb, analog things that mostly look pretty. Or are they? [JGJMatt] proves otherwise with their stunning DIY smart pocket watch. It is essentially a cheap smart watch from Amazon stuffed into the shell of an old pocket watch, but you know it’s not quite that simple.

On the easier side of things, [JGJMatt] had to come up with a 3D-printed bracket to hold the smart watch’s guts. On the harder end of the spectrum, he ended up building the charging port into the crown, where the latch used to be.

This is a beautiful build for sure, and a great way to reuse something that might otherwise end up thrown away or melted down.

Looking for a cool alternative pocket watch that’s a little easier to build? Check out [JGJMatt]’s pocket sundial.