Read Utility Meters Via SDR To Fill Out Smart Home Stats

July 30, 2024 by Donald Papp 21 Comments

[Jeff Sandberg] has put a fair bit of effort into adding solar and battery storage with associated smarts to his home, but his energy usage statistics were incomplete. His solution was to read data from the utility meter using RTL-SDR to fill in the blanks. The results are good so far, and there’s no reason similar readings for gas and water can’t also be done.

[Jeff] uses the open source home automation software Home Assistant which integrates nicely with his solar and battery backup system, but due to the way his house is wired, it’s only aware of about half of the energy usage in the house. For example, [Jeff]’s heavy appliances get their power directly from the power company and are not part of the solar and battery systems. This means that Home Assistant’s energy statistics are incomplete.

Fortunately, in the USA most smart meters broadcast their data in a manner that an economical software-defined radio like RTL-SDR can access. That provided [Jeff] with the data he needed to get a much more complete picture of his energy usage.

While getting data from utility meters is conceptually straightforward, actually implementing things in a way that integrated with his system took a bit more work. If you’re finding yourself in the same boat, be sure to look at [Jeff]’s documentation to get some ideas.

Junk Bin Build Lets You Test Fuel Injectors On The Cheap

July 30, 2024 by Dan Maloney 32 Comments

Fiddle around with cars long enough and you’ll realize two things: first, anything beyond the simplest repairs will probably require some kind of specialized tool, and second, those tools can be prohibitively expensive. That doesn’t mean you’re out of luck, though, especially if you’ve got scrap galore and a DIY spirit, as this junk bin fuel injector test stand ably demonstrates.

[Desert Rat Racer]’s test rig is designed to support four injectors at once and to test them under conditions as close as possible to what they’ll experience when installed. To that end, [Rat] mounted a junk intake manifold to a stand made from scrap wood and metal found by the side of the road. A pickle jar serves as a reservoir for the test fluid — he wisely used mineral spirits as a safer substitute for gasoline — and a scrap electric fuel pump pressurizes a junk fuel rail, which distributes fuel to the injectors under test.

For testing, the injectors are wired up to an electric injector tester, which is one of the few off-the-shelf components in the build. The fuel pump and injectors are powered by the 12 volt rail of a scrapped PC power supply. Just being able to watch the spray pattern is often enough to find a faulty injector, but in case a more quantitative test is indicated, each injector is positioned over a cheap glass cylinder to catch the test fluid, and scraps of a tape measure are used to measure the depth of the collected fluid. No fancy — and expensive — graduated cylinders required.

While we truly respect the hackiness of [Desert Rat Racer]’s build, the concept of avoiding buying tactical tools is foreign to us. We understand the logic of not dropping a ton on a single-use tool, but where’s the fancy blow-molded plastic case?

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Building The Unreleased Lemmings Arcade Cabinet From 1991

July 29, 2024 by Maya Posch 7 Comments

Back in the early 90s the world was almost graced with an arcade version of Lemmings, but after a few board revisions it was abandoned in 1991. Now the folk over at UK-based [RMC – The Cave] on YouTube have managed to not only get their mitts on a nearly finished prototype board, but have also designed and built a period-appropriate cabinet to go with it. This involved looking at a range of arcade cabinets created by Data East and picking a design that would allow both for the two-player mode of the game, and fit the overall style.

Arcade cabinets came in a wide range of cabinet styles and control layouts, largely defined by the game’s requirements, but sometimes with flourishes to distinguish the cabinet from the hundred others in the same arcade.

In this particular case the typical zig-zag (Z-back) style was found to be a good fit as on the Data East Night Slashers 1993-era cabinet, which then mostly left the controls (with two trackballs) and cabinet art to figure out. Fortunately there is plenty of inspiration when it comes to Lemmings art, leading to the finished cabinet with the original mainboard, the JAMMA wiring harness with MultiPi JAMMA controller, a 19″ CRT monitor and other components including the 3D printed controls panel.

With more and more new arcades popping up in the US and elsewhere, perhaps we’ll see these Lemmings arcade cabinets appear there too, especially since the ROMs on the prototype board were dumped for convenient MAME-ing.

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A bright orange sailboat with solar panels on the wing sail and the hull of the craft. A number of protuberances from the wing are visible containing instruments and radio equipment.

Saildrones Searching The Sea For Clues To Hurricane Behavior

July 29, 2024 by Navarre Bartz 26 Comments

Hurricanes can cause widespread destruction, so early forecasting of their strength is important to protect people and their homes. The US National Oceanic and Atmospheric Administration (NOAA) is using saildrones to get better data from inside these monster storms.

Rising ocean temperatures due to climate change are causing hurricanes to intensify more rapidly than in the past, although modeling these changes is still a difficult task. People on shore need to know if they’re in store for a tropical storm or a high strength hurricane to know what precautions to take. Evacuating an area is expensive and disruptive, so it’s understandable that people want to know if it’s necessary.

Starting with five units in 2021, the fleet has gradually increased in size to twelve last summer. These 23ft (7m), 33ft (10m), or 65ft (20m) long vessels are propelled by wing sails and power their radio and telemetry systems with a combination of solar and battery power. No fossil fueled vessel can match the up to 370 days at sea without refueling that these drones can achieve, and the ability to withstand hurricane winds and sea conditions allow scientists an up-close-and-personal look at a hurricane without risking human lives.

We’ve covered how the data gets from a saildrone to shore before, and if you want to know how robots learn to sail, there’s a Supercon talk for that.

Thanks to [CrLz] for the tip!

Getting Linux Process List Without Forking Using Just A Bash Script

July 29, 2024 by Maya Posch 16 Comments

The ps command is extremely useful when you want to get some quick information on active system processes (hence the name), especially followed by piping it into grep and kin for some filtering. One gotcha is of course that ps doesn’t run in the current shell process, but is forked off into its own process, so what if everything goes wrong and you absolutely need to run ps aux on a system that is completely and utterly out of fresh process IDs to hand out? In that scenario, you fortunately can write a shell script that does the same, but all within the same shell, as [Isabella Bosia] did, with a Bash shell script.

The how and why is mostly covered in the shell script itself, using detailed comments. Initially the hope was to just read out and parse the contents of /proc/<pid>/status, but that doesn’t have details like CPU%. The result is a bit more parsing to get the desired result, as well as a significant amount of cussing in the comments. Even if it’s not entirely practical, as the odds of ending up on a system with zero free PIDs are probably between zero and NaN, but as an ‘entertaining’ job interview question and example of all the fun things one can do with shell scripting it’s definitely highly recommended.

A black and brown planner opened like a laptop. Inside is a greyscale eink phone inside a brown piece of MDF on top, and a black keyboard fills the bottom half.

Foliodeck Squeezes A Writerdeck Into A Planner

July 29, 2024 by Navarre Bartz 2 Comments

When it comes to writing, sometimes a computer or smartphone is just too distracting to keep on task. [vagabondvivant] found this to be the case and rolled their own distraction-free writing tool, the Foliodeck.

With the increasing availability of parts for cyberdecks, it’s not too surprising to see we’re seeing the emergence of the writerdeck. Typically designed to be a no frills word processing device, they are designed to help their creators focus on writing and not be subject to the myriad notifications present trying to work with a more general computing device or smartphone.

In this case, [vagabondvivant] took a classy looking planner folio and removed its paper management components to leave a fabric and leather shell. The heart of the assembly is a HiSense A5 eink smartphone magnetically attached to a piece of MDF cut to mate the phone to the planner shell. A 10 Ah powerbank slots into the MDF below the keyboard which is also magnetically attached, and the whole thing zips up nicely. Future improvements are planned like a hinge, so it doesn’t have to be propped against something and a custom-built mechanical keyboard.

This isn’t the first writerdeck we’ve seen, and we’ve seen some other writer-focused decks and typewriter replacements.

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Three different keyboard devices with greyscale LCDs on top are on a white table. In the back left is a beige one with grey keys, front and center is a black model, and to the right is a translucent blue model with black keys being held up by a hand.

A Brief History Of AlphaSmart

July 29, 2024 by Navarre Bartz 18 Comments

There are a handful of gadgets that do one thing so well that they become cult classics long after the company that made them has moved on or closed up shop. [This Does Not Compute] takes us through the history of the AlphaSmart word processor which started as an educational tool, but finds itself in many a writer’s bag today.

The original AlphaSmart bears more than a passing resemblance to its Apple contemporaries since the company was founded by two Apple engineers. The Cupertino company didn’t see the value in the concept, but didn’t lean on any non-competes to keep the pair from pursuing the idea on their own time either. What resulted was a dead simple word processor that could be had for 1/5 of what a new computer typically cost in the era, which was particularly attractive for the target market of schools.

After several successful years, the pressure of PDAs and then smartphones from one side and cheaper laptops from the other meant school districts no longer wanted single-purpose devices when they could have a fully-fledged computing experience for students. We wonder if that was the right call, with so many now wanting distraction-free devices, but it was the end of the road for the company either way.

Our own [Kristina Panos] and [Tom Nardi] have shown us the guts of the Neo and of one of its competitors, the Writer, respectively. If you have a Neo of your own in need of replacement keycaps, you can print them.

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