Mothballing Rosalind: How To Put A Space Mission In Storage

April 11, 2022 by Dan Maloney 13 Comments

In planetary exploration circles, Mars has quite a bad reputation. The Red Planet has a habit of eating spacecraft sent there to explore it, to the degree that nearly half of the missions we’ve thrown at it have failed in one way or another. The “Mars Curse” manifests itself most spectacularly when landers fail to negotiate the terminal descent and new billion-dollar craters appear on the Martian regolith, while some missions meet their doom en route to the planet, and an unlucky few have even blown up on the launchpad.

But the latest example of the Mars Curse, the recent cancellation of the second half of the ExoMars mission, represents a new and depressing failure mode: war — specifically the Russian invasion of Ukraine. The international outrage over the aggression resulted in economic sanctions and diplomatic isolation of Russia, which retaliated by ending its partnership with the European Space Agency (ESA), depriving the mission of its launch vehicle and dooming the mission that would have landed the rover Rosalind Franklin on Oxia Planum near the Martian Equator in 2023.

While there’s still a chance that administrators and diplomats will work things out, chances are slim that it will be in time for the narrow launch window that the mission was shooting for in September of 2022. That means the Rosalind Franklin, along with all the other flight hardware that was nearly ready to launch, will have to be put in storage at least until the next launch window opens in 2024. That begs the question: how does one put a complex spacecraft into storage? And could such mothballing have unintended consequences for the mission when it eventually does fly?

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This End Table Conceals A Close Encounter

April 11, 2022 by Jenny List 18 Comments

If you’re of a Certain Age, perhaps you had a train set as a child. An oval of track, a loco, and some rolling stock; it matters not whether it was Thomas the Tank Engine or a large express train — they were at the time a pretty cool toy. Move forward a few decades, and model railways have become either super-expensive room-filler layouts, or have sunk low as novelty Christmas ornaments, so that the basic loop of track is in dire need of rescue. Perhaps [Peter Waldraff] can help, with a beautifully-constructed N gauge circular layout concealed in an end table. Even better, when you examine it closely, it becomes apparent that this is no ordinary train set, it’s a scene from Close Encounters Of The Third Kind.

This is a project of two equally well-made parts, the piece of furniture and the train. The former is entirely scratch-built, with a cylindrical outside made from carefully cut rings of plywood and a sliding riser mechanism in the centre with a concrete counterweight. Slide the cylinder upwards, and the layout is revealed — a scratch-built hill in the centre of the ring of track and the lit-up underside of the UFO above it. As the train goes round the track, it even triggers a set of crossing lights and sounds for extra realism. The full story can be seen in the video below the break, and is well worth a watch.

We’ve covered more than one concealed model railway layout in the past, and it comes as no surprise when browsing to find that [Peter]’s work has featured here before.

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The end result - motorized window in a silver stainless steel frame, with the linear actuators and gas struts, shown from the outside half-open.

Swing Gate Motors Come To Help For Opening A Giant Servery Window

April 11, 2022 by Arya Voronova 34 Comments

[Martin Roberts] wrote to us, telling us about a build that his company, [Ocean View Workshop], was tasked with. Creating a four meter wide window able to open vertically is no small feat, and it had to be custom-built because the local company building such windows wasn’t comfortable working with anything other than aluminum — insufficient for the window’s scale. With massive weight of the glass alone, structural requirements for supporting it, and the mechanical loads to be applied, some careful planning was in order.

To start with, this window had to be motorized, as an average person wouldn’t be capable of pulling it upwards. Not satisfied with the linear actuator choice available, they went to a hardware store and found some swing gate actuators that, in workshop tests, proved themselves to be more than capable of handling way over the weight required. In fact, they were capable of lifting [Martin] himself off the ground without much hassle.

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Coin Acceptors Are Higher-Tech Than You Think

April 10, 2022 by Al Williams 16 Comments

Coin-operated machines have a longer history than you might think. Ancient temples used them to dispense, for example, holy water to the faithful in return for their coins. Old payphones rang a bell when you inserted a coin so the operator knew you paid. Old pinball machines had a wire to catch things with holes in the middle so you couldn’t play with washers. But like everything else, coin acceptors have advanced quite a bit. [Electronoobs] shows a unit that can accept coins from different countries and it is surprisingly complex inside. He used what he learned from the teardown to build his own Arduino-based version.

For scale, there is the obligatory banana. Inside the box there are several induction coils and some photo electronics. In particular, there are two optical sensors that watch the coin roll down a ramp. This produces two pulses. The width of the pulse indicates the diameter of the coin, and the time between the pulses tells its speed.

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Two pairs of boards described in the article, with toggle switches and RCA jacks, shown interconnected, LEDs on all four boards lit up.

Boards For Playful Exploration Of Digital Protocols

April 10, 2022 by Arya Voronova 1 Comment

Teaching people efficiently isn’t limited to transmitting material from one head to another — it’s also about conveying the principles that got us there. [Mara Bos] shows us a toolkit (Twitter,
nitter link) that you can arm your students with, creating a small playground where, given a set of constraints, they can invent and figure communication protocols out on their own.

This tool is aimed to teach digital communication protocols from a different direction. We all know that UART, I2C, SPI and such have different use cases, but why? Why are baud rates important? When are clock or chip select lines useful? What’s the deal with the start bit? We kinda sorta figure out the answers to these on our own by mental reverse-engineering, but these things can be taught better, and [Mara] shows us how.

Gently guided by your observations and insights, your students will go through defining new and old communication standards from the ground up, rediscovering concepts like acknowledge bits, bus contention, or even DDR. And, as you point out that the tricks they just discovered have real-world counterparts, you will see the light bulb go on in their head — realizing that they, too, could be part of the next generation of engineers that design the technologies of tomorrow.

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Hackaday Links: April 10, 2022

April 10, 2022 by Dan Maloney 19 Comments

A funny thing happened on the way to the delta. The one on Jezero crater on Mars, that is, as the Perseverance rover may have captured a glimpse of the parachute that helped deliver it to the Red Planet a little over a year ago. Getting the rover safely onto the Martian surface was an incredibly complex undertaking, made all the more impressive by the fact that it was completely autonomous. The parachute, which slowed the descent vehicle holding the rover, was jettisoned well before the “Sky Crane” deployed to lower the rover to the surface. The parachute wafted to the surface a bit over a kilometer from the landing zone. NASA hasn’t confirmed that what’s seen in the raw images is the chute; in fact, they haven’t even acknowledged the big white thing that’s obviously not a rock in the picture at all. Perhaps they’re reserving final judgment until they get an overflight by the Ingenuity helicopter, which is currently landed not too far from where the descent stage crashed. We’d love to see pictures of that wreckage.

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Robotic Boat Rides High On PVC Pipe Pontoons

April 10, 2022 by Tom Nardi 11 Comments

If you want to build your own rover, there’s plenty of cheap RC trucks out there that will provide a serviceable chassis to work with. Looking to go airborne with a custom drone? Thanks to the immense popularity of first-person view (FPV) flying, you’ll find a nearly infinite variety of affordable fixed wing and quadcopter platforms out there to chose from. But when it comes to robotic watercraft, the turn-key options aren’t nearly as plentiful; the toys are all too small, and the commercial options are priced for entities that have an R&D budget to burn. For amateur aquatic explorers, creativity is the name of the game.

Take for example this impressive vessel built by [wesgood]. With a 3D printed electronics enclosure mounted to a pair of pontoons made of cheap 4-inch PVC pipe available from the hardware store, it provides a stable platform without breaking the bank. Commercial jet drive units built into the printed tail caps for the pipes provide propulsion, and allow the craft to be steered through differential thrust. Without rudders or exposed propellers, this design is particularly well-suited for operating in shallow waters.

A removable electronics tray allows for easy access.

Perched high above the water, the electronics box contains a Raspberry Pi 2, BU353 USB GPS receiver, and a Arduino Mega 2560 paired with a custom PCB that offers up convenient ports to connect a dual-channel Cytron 3 amp motor driver and Adafruit BNO055 9-DOF IMU. Power is provided by two 6,000 mAh LiPo batteries mounted low in the pontoons, and a matching pair of Adafruit current/voltage sensors are used to keep track of the energy budget. A small USB WiFi dongle with an external antenna plugged into the Pi offers up a WiFi network that [wesgood] can connect to with an iPad for control.

If the control software for the craft looks particularly well-polished, it’s probably because [wesgood] just so happens to be a professional developer with a focus on mobile applications. While we’re a bit skeptical of using WiFi for a critical long-distance link, we can’t deny that the iPad allows for a very slick interface. In addition to showing the status of the craft’s various systems, it lets the user either take manual control or place waypoints for autonomous navigation — although it sounds like that last feature is only partially implemented right now.

We love this design, and are eager to see more as the project develops. Recently [wesgood] experimented with payloads that can be suspended from the bottom of the electronics box, specifically a sonar module for performing bathymetric observations. There’s considerable interest in crowd sourced depth maps for inland waterways, and a robotic craft that can reliably chart these areas autonomously is certainly a step up from having to collect the data manually.