PVC ROV is a study in MPV

Low Buck PVC ROV IS Definitely A MVP

December 2, 2021 by 8 Comments

Do you have a hundred bucks and some time to kill? [Peter Sripol] invites you to come along with him and build a remotely operated submarine with only the most basic, easily accessible parts, as you can see in the video below the break.

Using nothing more than PVC pipe, an Ethernet cable, and a very basic electrical system, [Peter] has built a real MVP of a submarine. No, not Most Valuable Player; Minimum Viable Product. You see, there’s not a microcontroller, motor controller, sensor, or MOSFET to be found except for that which might reside inside the knock-off GoPro style camera which is encased in a candle wax sealed enclosure.

Instead, simple brushed motors live right out in the open water. Single pole double throw switches are connected to 100 feet of Ethernet cable and control the relays powering the motors. The camera signal is brought back to the controller through the same cable. Simple is the key to the build, and we have to admit that for all of its Minimum Viability, the little ROV has a lot going for it. [Peter] even manages to use the little craft to find and make possible the retrieval of a crustacean encrusted shopping cart from a saltwater canal. Not bad, little rover, not bad.

Also noteworthy is that the video below has its own PVC ROV Sea Shanty, which is something you just don’t hear every day.

Underwater ROV builds are the sort of thing almost every hacker thinks about doing at least once, and some hackers even include Lego, magnets, and balloons in their builds! Continue reading “Low Buck PVC ROV IS Definitely A MVP” →

Illustrated Kristina with an IBM Model M keyboard floating between her hands.

Keebin’ With Kristina: The One With The Cat Keyboard

December 2, 2021 by 8 Comments

Special thanks to [Maarten], who stumbled upon this old gem of a geekhack thread by [suka]. It’s essentially a show and tell of their DIY keyboard journey, complete with pictures. [suka]’s interest started with a yen for ergonomic keyboard layout alternatives. They soon found the geekhack forum and started lurking around, practicing layouts like Neo and AdNW, which [suka] still uses today.

A pair of num pads wired up to a Teensy becomes a keyboard.When it was time to stop lurking and start building something, [suka] got plenty of support from the community. They knew they wanted a split ortho with a trackpoint and plenty of thumb keys. [suka] started by building them from old Cherry keyboards, which are easier to come by in Germany.

The first build was a pair of num pads turned landscape and wired up to a Teensy, but [suka] wanted those sweet, clacky Cherry MX switches instead of MLs. So the second version used a pair of sawed-off num pads from old MX boards.

When the Truly Ergonomic came out, it got [suka] interested in one-piece splits. Plus, they were tired of carrying around a two-piece keyboard. So their next build was a sexy monoblock split with a laser-sintered case and keycaps. But that was ultimately too uncomfortable, so [suka] went back to split-splits.

Everyone takes a different path into and through this hobby, and they’re all likely to be interesting. Is yours documented somewhere? Let us know.

What Could Have Been: The Dygma Raise

I do some streaming here and there, mostly for the sense of focus I get out of being live on camera. I like to find out what my people in chat are clacking on, and one of them told me they have a staggered split called the Dygma Raise. I hadn’t heard of it before that day, but this keyboard has been around for a few years now.

This same person told me that Dygma might make an ortholinear version sometime soon, but apparently Dygma wanted it that way from the beginning. According to the timely video below sent to the tips line by [deʃhipu], Dygma’s original plan was a split ortho with few keys and presumably a layer system.

Continue reading “Keebin’ With Kristina: The One With The Cat Keyboard” →

Play Doom Or GTA V With Your Own Custom Controller And Xbox Emulator

December 2, 2021 by 11 Comments

[Arnov] is bringing his own custom-made controller to the party and it is sure to impress. The design appears to have been inspired by the Xbox controller layout. Two joysticks for fine control of game characters, 4 face buttons, and two shoulder buttons. He opted for all through-hole components to make the assembly easier. No messing with tiny surface mount components here. We really appreciate the detail given to the silkscreen and the homage paid to a staple of retro gaming.

We were pretty impressed with how smoothly the controller translated to the game. He mentioned that was a huge improvement over his previous design. His original design had buttons instead of joysticks, but switching to joysticks gave him much better in-game control. That could also have a lot to do with the Xbox controller emulator running the background, but still.

Given that gift-giving season is upon us, you could really impress the video game enthusiast in your life with this as a custom gift. You could even run Retro games like Doom if you hook it up to a RetroPie. That ought to get a few people’s attention.

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Two Mars Orbiters Chatted For Atmospheric Science

December 2, 2021 by 9 Comments

Mission extensions for interplanetary robot explorers are usually continuations of their primary mission. But sometimes the hardware already on board are put to novel uses. European Space Agency has started using radio equipment on board two Mars orbiters to probe the Martian atmosphere.

The scientific basis is straightforward: radio signals are affected by whatever they had traveled through. When transmitting data, such effects are noises to be minimized. But we can also leverage it for atmospheric science here on Earth. ESA applied the same concept at Mars: by transmitting a known signal from one Mars orbiter to another, changes in the received signal tells scientists something about the Martian atmosphere between them.

So the theory sounds good, but the engineering implementation took some work. Most radio equipment on board ESA’s orbiters were not designed to talk to each other. In fact they were deliberately different to minimize interference. However, both Mars Express and Trace Gas Orbiter were designed to act as data relays for surface probes, and not just the one they each carried to Mars. Thus their related radio gear were flexible enough to be adapted to this experiment.

These two machines launched over a decade apart. Yet they could now communicate with each other in Mars orbit using radios originally designed for talking to the surface. In the near future such chatter will probably be limited, as Trace Gas Orbiter is still in the middle of its primary mission. But this success lets ESA think about how much further to push the idea in the future. In the meantime Mars Express will continue its observation of Mars, doing things like giving us context on Perseverance rover landing.

Listening To The Sounds Of An 1960s Military Computer

December 1, 2021 by 44 Comments

Restoring vintage computers is the favorite task of many hardware hackers. Retrocomputing probably makes you think of home computer brands like Commodore, Amiga, or Apple but [Erik Baigar] is deeply into collecting early military computers from the UK-based Elliott company. Earlier this year he made a detailed video that shows how he successfully brought an Elliott 920M from the 1960s back to life.

It is quite amazing that the Elliott company already managed to fit their 1960s computer into a shoebox-sized footprint. As computers had not yet settled on the common 8bit word size back then the Elliott 900 series are rather exotic 18bit or 12bit machines. The 920M was used as a guidance computer for European space rockets in the 1960s and ’70s but also for navigational purposes in fighter jets until as late as 2010.

Opening up the innards of this machine reveals some exotic quirks of early electronics manufacturing. The logic modules contain multilayer PCBs where components were welded instead of soldered onto thin sheets of mylar foil that were then potted in Araldite.

To get the computer running [Erik Baigar] first had to recreate the custom connectors using a milling machine. He then used an Arduino to simulate a paper tape reader and load programs into the machine. An interesting hack is when he makes the memory reading and writing audible by simply placing a radio next to the machine. [Erik Baigar] finishes off his demonstration of the computer by running some classic BASIC games like tic-tac-toe and a maze creator.

If you would like to code your own BASIC programs on more modern hardware you should check out this BASIC interpreter for the Raspberry Pi Pico.

Video after the break.

Continue reading “Listening To The Sounds Of An 1960s Military Computer” →

A scaled down version of a pedestrian crossing signal

Don’t Walk Past This 3D Printed Pedestrian Crossing Light

December 1, 2021 by 9 Comments

There’s just something so pleasing about scaled-down electronic replicas, and this adorable 3D printed pedestrian crossing light by [sjm4306] is no exception.

Although a little smaller than its real-world counterpart, the bright yellow housing and illuminated indicators on this pedestrian lamp are instantly recognizable due to their ubiquitous use throughout the United States. The handful of printed parts are held together using friction alone, which makes assembly a literal snap. The ‘safety grill’ with its many angles ended up being one of the most tedious parts of the build process, but the effort was definitely justified, as it just wouldn’t look right without it.

A suitably minuscule ATtiny85 drives a pair of LED strips that effectively mimic the familiar symbols for ‘Walk’ and ‘Don’t Walk’. [sjm4306] has designed the board and case in such a way to accommodate a variety of options. For example, there’s just enough room to squeeze in a thin battery, should you want to power this contraption on-the-go. If you don’t have an ATtiny85 on hand, the board also supports an ATmega328p or even an ESP8266.

All the build details are available over on Hackaday.io. While it’s billed as a ‘night light’, we think this could be an awesome platform for an office toy, similar to this office status light project. Or if you’ve somehow already got your hands on a full-size pedestrian lamp, why not hook it up to the Internet?

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SuperCapacitors Vs Batteries Again

December 1, 2021 by 41 Comments

Supercapacitors are definitely not the same as batteries, we all know that. They tend to have a very low operating voltage, and due to their operating principle of storing charge on parallel plates, their discharge curve is quite unfriendly for modern microcontroller devices. Energy storage efficiency per unit volume is also low compared with modern lithium polymer (LiPo) batteries so all in all they don’t look all that useful for many of our projects. However, as [Andreas Spiess’] latest video demonstrates, they do have some redeeming features that might make them useful for certain embedded applications.

The low operating voltage initially looks like an issue for devices operating at a typical 3.3V, and it’s tempting to simply wire a few in series and roll with it. But as [Andreas] explains in his typically clear manner, it would be necessary to have a complex power stage, operating in buck mode with capacitor voltage above the required level, and in boost mode when it heads below. Too complex – it’s much easier to simply stick with a low voltage bank of paralleled supercaps, and just operate always in boost mode. Even doing this, you’re not realistically going to get more than a handful of hours operating voltage with an always active device.

So why bother at all with supercaps, surely using a LiPo is so much easier and better? In many cases the answer is definitely a yes. But LiPo cells must not be charged in freezing temperatures (apart from certain special low temp products), else the cell can rapidly be destroyed due to lithium metal deposition at the anode. Also you need to be careful charging them, especially when they’re heavily discharged, as they are easily damaged without the proper treatment. LiPo cells operate based on chemical principles – lithium ions literally have to move around inside the structure, and eventually the battery will wear out.

Supercapacitors have the advantage of very long life (but sometimes, they do leak) much more aggressive charging and discharging behaviours and will operate down to very low temperatures. This makes them very useful when a large amount of power is available sporadically (for super fast charge cycles) or in places where temperatures stay persistently very low, such as up a mountain were solar will work, albeit slowly, but LiPo batteries will definitely not be suitable.

Other battery chemistries are available, such as Lithium Iron Phosphate which can tolerate the cold. Also you can always just insulate the battery with an integrated heater and preheat the battery to a safe charging temperature as well. So, just like everything with electronics, it’s important to choose the correct parts for your application, and it all starts with the power source. Supercapacitors might just hit an appropriate price/performance point for that special application you had in mind.

Supercapacitors aren’t really suitable for many applications, like powering an eBike or running your laptop, but hey, they did it anyway.

Continue reading “SuperCapacitors Vs Batteries Again” →