Author: Maya Posch

1429 Articles

Smart Thermostats Pitched For Texas Homes To Relieve Stressed Grid

November 14, 2024 by 86 Comments

It’s not much of a secret that Texas’ nearly completely isolated grid is in a bit of a pickle, with generating capacity often being handily outstripped during periods of extreme demand. In a latest bid to fight this problem, smart thermostats are being offered to customers, who will then participate in peak-shaving. The partnership between NRG Energy Inc., Renew Home LLC, and Alphabet Inc. will see about 650,000 of these thermostats distributed to customers.

For customers the incentive would be mostly financial, though the details on the potential cost savings seem scarce. The thermostats would be either a Vivint (an NRG company) or Google Nest branded one, which would be controlled via Google Cloud, allowing for thermostat settings to be changed to reduce the load on the grid. This is expected to save ‘300 MW’ in the first two years, though it’s not clear whether this means ‘continuously’, or intermittent like with a peaker natural gas plant.

Demand curtailment is not a new thing, with it being a big thing among commercial customers in South Korea, as we discussed within the topic of vehicle-to-grid energy storage. Depending on how it is implemented it can make a big difference, but it’ll remain to see how regular consumers take to the idea. It also provides more evidence for reducing grid load being a lot easier than adding grid-level storage, which is becoming an increasingly dire topic as more non-dispatchable solar and wind power is added to the grid.

Making Sense Of Real-Time Operating Systems In 2024

November 13, 2024 by 52 Comments

The best part about real-time OS (RTOS) availability in 2024 is that we developers are positively spoiled for choice, but as a corollary this also makes it a complete pain to determine what the optimal choice for a project is. Beyond simply opting for a safe choice like FreeRTOS for an MCU project and figuring out any implications later during the development process, it can pay off massively to invest some time up-front matching the project requirements with the features offered by these various RTOSes. A few years ago I wrote a primer on the various levels of ‘real-time’ and whether you may even just want to forego an RTOS at all and use a simple Big Loop™ & interrupt-based design.

With such design parameters in mind, we can then look more clearly at the available RTOS options available today, which is the focus of this article. Obviously it won’t be an exhaustive comparison, and especially projects like FreeRTOS have seen themselves customized to various degrees by manufacturers like ST Microelectronics and Espressif, among others. This also brings to the forefront less pleasant considerations, such as expected support levels, as illustrated by e.g. Microsoft’s Azure RTOS (formerly ThreadX) recently getting moved to the Eclipse Foundation as the Eclipse ThreadX open source project. On one hand this could make it a solid open-source licensed RTOS, or it could have been open sourced because Microsoft has moved on to something else and cleared out its cupboard.

Thus without further ado, let’s have a look at RTOSes in 2024 and which ones are worth considering, in my opinion.

Continue reading “Making Sense Of Real-Time Operating Systems In 2024” →

NASA Announces New Trials For In-Space Laser Welding

November 13, 2024 by 20 Comments

In-space manufacturing is a big challenge, even with many of the same manufacturing methods being available as on the ground. These methods include rivets, bolts, but also welding, the latter of which was first attempted fifty years ago by Soviet cosmonauts. In-space welding is the subject of a recently announced NASA collaboration. The main aspects to investigate are the effects of reduced gravity and varying amounts of atmosphere on welds.

The Soviets took the lead in space welding when they first performed the feat during the Soyuz-6 mission in 1969. NASA conducted their own welding experiments aboard Skylab in 1973, and in 1984, the first (and last) welds were made in open space during an EVA on the Salyut-7 mission. This time around, NASA wants to investigate fiber laser-based welding, as laid out in these presentation slides. The first set of tests during parabolic flight maneuvers were performed in August of 2024 already, with further testing in space to follow.

Back in 1996 NASA collaborated with the E.O. Paton Welding Institute in Kyiv, Ukraine, on in-space welding as part of the ISWE project which would have been tested on the Mir space station, but manifesting issues ended up killing this project. Most recently ESA has tested in-space welding using the same electron-beam welding (EBW) approach used by the 1969 Soyuz-6 experiment. Electron beam welding has the advantage of providing great control over the weld in a high-vacuum environment such as found in space.

So why use laser beam welding (LBW) rather than EBW? EBW obviously doesn’t work too well when there is some level of atmosphere, is more limited with materials and has as only major advantage that it uses less power than LBW. As these LBW trials move to space, they may offer new ways to create structure and habitats not only in space, but also on the lunar and Martian surface.

Featured image: comparing laser beam welding with electron beam welding in space. (Source: E. Choi et al., OSU, NASA)

The End Of Ondsel And Reflecting On The Commercial Prospects For FreeCAD

November 12, 2024 by 106 Comments

Within the world of CAD there are the well-known and more niche big commercial players and there are projects like FreeCAD that seek to bring a OSS solution to the CAD world. As with other OSS projects like the GIMP, these OSS takes on commercial software do not always follow established user interactions (UX), which is where Ondsel sought to bridge the gap by giving commercial CAD users a more accessible FreeCAD experience. This effort is now however at an end, with a blog post by Ondsel core team member [Brad Collette] providing the details.

The idea of commercializing OSS is by no means novel, as this is what Red Hat and many others have done for decades now. In our article on FOSS development bounties we touched upon the different funding models for FOSS projects, with the Linux kernel enjoying strong commercial support. The trick is of course to attract such commercial support and associated funding, which is where the development on the UI/UX and feature set of the core FreeCAD code base was key. Unfortunately the business case was not strong enough to attract such commercial partners and Ondsel has been shutdown.

As also discussed on the FreeCAD forum, the Ondsel codebase will likely be at least partially merged into the FreeCAD code, ending for now the prospect of FreeCAD playing in the big leagues with the likes of AutoCAD.

Thanks to [Brian Harrington] for the tip.

A Brief History Of Cyrix, Or How To Get Sued By Intel A Lot

November 12, 2024 by 29 Comments

In a new installment on computer history, [Bradford Morgan White] takes us through the sordid history of Cyrix, as this plucky little company created the best math co-processors (FasMath) and then a range of interesting x86-compatible CPUs that would give competing x86 CPUs a run for their money. Even though Cyrix played by the rules of licensing agreements, Intel would keep suing Cyrix repeatedly since the 1980s well into 1990s, for a total of seventeen times until Cyrix counter-sued for patent violations in May of 1997.

This case was settled between Cyrix and Intel, with a cross-licensing agreement established. Unfortunately these mounting legal costs and the stresses of keeping up with the competition (i.e. Intel) was proving too much and Cyrix was sold off to National Semiconductor, who wasn’t enthusiastic about competing with Intel. After this Cyrix got split up into Geode (sold to AMD) and Cyrix Technologies (sold to VIA). Interestingly, VIA’s x86 patent licenses and patents ended up being the foundation of Zhaoxin: a joint venture between VIA and Shanghai’s government which produces x86 CPUs for primarily the Chinese market.

We looked at the Cyrix Cx486DLC processor a while ago, and why their 386 upgrade options were perhaps not that great. Their later CPUs have however left a strong legacy that seems to endure in some way to this day.

Minuteman ICBM Launch Tests Triple Warheads

November 12, 2024 by 75 Comments

On November 5th, the United States launched an LGM-30G Minuteman III ICBM from Vandenberg Space Force Base in California. Roughly 30 minutes later the three warheads onboard struck their targets 4,200 miles (6,759 km) away at the Reagan Test Site in the Marshall Islands. What is remarkable about this test is not that one of these ICBMs was fired — as this is regularly done to test the readiness of the US’ ICBMs — but rather that it carried three warheads instead of a single one.

Originally the Minuteman III ICBMs were equipped with three warheads, but in 2014 this was reduced to just one as a result of arms control limits agreed upon with Russia. This New Start Treaty expires in 2026 and the plan is to put three warheads back in the 400 operational Minuteman III ICBMs in the US’ arsenal. To this end a validation test had to be performed, yet a 2023 launch failed. So far it appears that this new launch has succeeded.

Although the three warheads in this November 5 launch were not nuclear warheads but rather Joint Test Assemblies, one of them contained more than just instrumentation to provide flight telemetry. In order to test the delivery vehicle more fully a so-called ‘high-fidelity’ JTA was also used which is assembled much like a real warhead, including explosives. The only difference being that no nuclear material is present, just surrogate materials to create a similar balance as the full warhead.

Assuming the many gigabytes of test data checks out these Minuteman III ICBMs should be ready to serve well into the 2030s at which point the much-delayed LGM-35 Sentinel should take over.

Why The Saturn V Used Kerosene For Its Hydraulics Fluid

November 11, 2024 by 38 Comments

We usually think of a hydraulic system as fully self-contained, with a hydraulic pump, tubing, and actuators filled with a working fluid. This of course adds a lot of weight and complexity that can be undesirable in certain projects, with the Saturn V Moon rocket demonstrating a solution to this which is still being used to this day. In a blast-from-the-past, a December 1963 article originally published in Hydraulics & Pneumatics details the kerosene-based hydraulics (fueldraulics) system for the S-1C stage’s gimbal system that controlled the four outer engines.

Rather than a high-pressure, MIL-H-5606 hydraulic oil-based closed loop as in the Saturn I, this takes kerosene from the high-pressure side of the F1 rocket engine’s turbopump and uses it in a single-pass system. This cuts out a separate hydraulic pump, a hydraulic reservoir, which was mostly beneficial in terms of reducing points of failure (and leaks), ergo increasing reliability. Such was the theory at the time at least, and due to issues with RP-1 kerosene’s relatively low flash point and differences in lubricity properties, ultimately RJ-1, RP-1 and MIL-H-5606 were used during checkout leading up to the launch.

In hindsight we know that this fueldraulic system worked as intended with all Saturn V launches, and today it’s still used across a range of aircraft in mostly jet engines and actuators elsewhere of the Boeing 777 as well as the F-35. In the case of the latter it only made the news when there was an issue that grounded these jets due to badly crimped lines. Since fueldraulics tends to be lower pressure, this might be considered a benefit in such cases too, as anyone who has ever experienced a hydraulic line failure can attest to.

Featured image: Gimbal systems proposed for the F-1, oxygen-kerosene engine with a fueldraulic system. (Source: Hydraulics & Pneumatics, 1963)