The Bluetooth SIG recently released the core specification for version 6.0 of Bluetooth. Compared to 5.x, it contains a number of changes and some new features, the most interesting probably being Channel Sounding. This builds upon existing features found in Bluetooth 5.x to determine the angle to, and direction of another device using Angle of Arrival (AoA) and Angle of Departure (AoD), but uses a new approach to much more precisely determine these parameters. as defined in the Technical Overview document for this feature.
In addition to this feature, there are also new ways to filter advertising packets, to reduce the number of packets to sift through (Decision-Based Advertising Filtering) and to filter out duplicate packets (Monitoring Advertisers). On a fundamental level, the Isochronous Adaptation Layer (ISOAL) received a new framing mode to reduce latency and increase reliability, alongside frame spacing now being negotiable and additional ways to exchange link layer information between devices.
As with any Bluetooth update, it will take a while before chipsets supporting it become widely available, and for the new features to be supported, but it gives a glimpse of what we can likely expect from Bluetooth-enabled devices in the future.
Launching things with electromagnetism is pretty fun, with linear induction motors being a popular design that finds use from everywhere in hobby designs like [Tom Stanton]’s to the electromagnetic launchers on new US and Chinese aircraft carriers. Although the exact design details differ, they use magnetic attraction and repulsion to create a linear motion on the propulsive element, like the sled in [Tom]’s design. Much like the electromagnetic catapults on a Gerald R. Ford-class carrier, electrical power is applied to rapidly move the sled through the channel, akin to a steam piston with a steam catapult.
Model airplane sparking its way through the launcher’s channel. (Credit: Tom Stanton, YouTube)
For [Tom]’s design, permanent magnets are used along both sides of the channel in an alternating north/south pole fashion, with the sled using a single wound coil that uses brushes to contact metal rails along both sides of the channel. Alternating current is then applied to this system, causing the coil to become an electromagnet and propel itself along the channel.
An important consideration here is the number of turns of wire on the sled’s coil, as this controls the current being passed, which is around 90 A for 100 turns. Even so, the fastest sled design only reached a speed of 44 mph (~71 km/h), which is 4 mph faster than [Tom]’s previous design that used coils alongside the channels and a sled featuring a permanent magnet.
One way to increase the speed is to use more coils on the sled, with a two-coil model launching a light-weight model airplane to 10.2 m/s, which is not only a pretty cool way to launch an airplane, but also gives you a sense of appreciation for the engineering challenges involved in making an electromagnetic catapult system work for life-sized airplanes as they’re yeeted off an aircraft carrier and preferably not straight into the drink.
There’s currently a significant amount of confusion around the full extent of the GPIO hardware issue in the Raspberry Pi RP2350 microcontroller, with [Ian] over at [Dangerous Prototypes] of Bus Pirate fame mentioning that deliveries of the RP2350-based Bus Pirate 5XL and 6 have been put on hold while the issue is further being investigated. Recorded in the MCU’s datasheet as erratum RP2350-E9, it was originally reported as only being related to the use of internal pull-downs, but [Ian] has since demonstrated in the primary issue ticket on GitHub that the same soft latching behavior on GPIO pins occurs also without pull-downs enabled.
Ian from Dangerous Prototypes demonstrating the RP2350-E9 issue in a Bus Pirate prototype without pull-ups.
When we first reported on this hardware bug in the RP2350’s A2 (and likely preceding) stepping there was still a lot of confusion about what this issue meant, but so far we have seen the Bus Pirate delay and projects like [AgustÃn Gimenez Bernad]’s LogicAnalyzer have opted for taking the RP2350 port out back. There are also indications that the ADC and PIO peripherals are affected by this issue, with workarounds only partially able to circumvent the hardware issue.
In the case of the Bus Pirate a potential workaround is the addition of 4.7 kOhm external pull-downs, but at the cost of 0.7 mA continuous load on the GPIO when pulled high and part of that when pulled low. It’s an ugly hack, but at the very least it might save existing boards. It also shows how serious a bug this is.
Meanwhile there are lively discussions about the issue on the Raspberry Pi forums, both on the E9 erratum as well as the question of when there will be a new stepping. The official statement by Raspberry Pi is still that ‘they are investigating’. Presumably there will be a Bx stepping at some point, but for now it is clear that the RP2350’s A2 stepping is probably best avoided.
Cutting grass with lasers works great in a test setup. (Credit: Allen Pan, YouTube)
Wouldn’t it be cool if you could cut the grass with lasers? Everyone knows that lasers are basically magic, and if you strap a diode laser or two to a lawn mower, it should slice through those pesky blades of grass with zero effort. Cue [Allen Pan]’s video on doing exactly this, demonstrating in the process that we do in fact live in a physics-based universe, and lasers are not magical light sabers that will just slice and dice without effort.
The first attempt to attach two diode lasers in a spinning configuration like the cutting blades on a traditional lawn mower led to the obvious focusing issues (fixed by removing the focusing lenses) and short contact time. Effectively, while these diode lasers can cut blades of grass, you need to give them some time to do the work. Naturally, this meant adding more lasers in a stationary grid, like creating a Resident Evil-style cutting grid, only for grass instead of intruders.
Does this work? Sort of. Especially thick grass has a lot of moisture in it, which the lasers have to boil off before they can do the cutting. As [Allen] and co-conspirator found out, this also risks igniting a lawn fire in especially thick grass. The best attempt to cut the lawn with lasers appears to have been made two years ago by [rctestflight], who used a stationary, 40 watt diode laser sweeping across an area. When placed on a (slowly) moving platform this could cut the lawn in a matter of days, whereas low-tech rapidly spinning blades would need at least a couple of minutes.
Obviously the answer is to toss out those weak diode lasers and get started with kW-level chemical lasers. We’re definitely looking forward to seeing those attempts, and the safety methods required to not turn it into a laser safety PSA.
Once the nerve center of Windows operating systems, the Control Panel and its multitude of applets has its roots in the earliest versions of Windows. From here users could use these configuration applets to control and adjust just about anything in a friendly graphical environment. Despite the lack of any significant criticism from users and with many generations having grown up with its familiar dialogs, it has over the past years been gradually phased out by the monolithic Universal Windows Platform (UWP) based Settings app.
Whereas the Windows control panel features an overview of the various applets – each of which uses Win32 GUI elements like tabs to organize settings – the Settings app is more Web-like, with lots of touch-friendly whitespace, a single navigable menu, kilometers of settings to scroll through and absolutely no way to keep more than one view open at the same time.
Unsurprisingly, this change has not been met with a lot of enthusiasm by the average Windows user, and with Microsoft now officially recommending users migrate over to the Settings app, it seems that before long we may have to say farewell to what used to be an intrinsic part of the Windows operating system since its first iterations. Yet bizarrely, much of the Control Panel functionality doesn’t exist yet in the Settings app, and it remain an open question how much of it can be translated into the Settings app user experience (UX) paradigm at all.
Considering how unusual this kind of control panel used to be beyond quaint touch-centric platforms like Android and iOS, what is Microsoft’s goal here? Have discovered a UX secret that has eluded every other OS developer?
Additive manufacturing (AM) has been getting a lot of attention over the years, with its use in construction a recurring theme. Generally this brings to mind massive 3D printers that are carted to construction sites and assemble entire homes on the spot. That’s the perspective with which a recent ZDNet article by [Rajiv Rao] opens, before asking whether AM in construction is actually solving any problems. As [Rajiv] notes, the main use of such on-site AM construction is for exclusive, expensive designs, such as ICON’s House Zero which leans into the extruded concrete printing method.
Their more reasonable Wolf Ranch residential homes in Texas also use ICON’s Vulcan II printer to print walls out of concrete, with a roof, electrical wiring, plumbing, etc. installed afterwards. Prices for these Wolf Ranch 3 to 4 bedroom houses range from about $450,000 to $600,000, and ICON has been contracted by NASA to work a way to 3D print structures on the Moon out of regolith.
3D printed home by WASP out of clay. (Credit: WASP)
Naturally, none of these prices are even remotely in the range of the first-home buyers, or the many economically disadvantaged who make up a sizable part of the population in the US and many other nations in the Americas, Africa, etc. To make AM in construction economically viable, it would seem that going more flatpack and on-site assembly is the way to go, using the age-old pre-fabrication (prefab) method of constructions.
This is the concept behind the University of Maine’s BioHome3D, which mainly uses PLA, wood fiber and similar materials to create modules that contain insulation in the form of wood fiber and cellulose. These modules are 3D printed in a factory, after which they’re carted off to the construction site for assembly, pretty much like any traditional prefab home, just with the AM step and use of PLA rather than traditional methods.
Prefab is a great way to speed up construction and already commonly used in the industry, as modules can have windows, doors, insulation, electrical wiring, plumbing, etc. all installed in the factory, with on-site work limited to just final assembly and connecting the loose bits. The main question thus seems to be whether AM in prefab provides a significant benefit, such as in less material wasted by working from (discarded) wood pulp and kin.
While in the article [Rajiv] keeps gravitating towards the need to use less concrete (because of the climate) and make homes more affordable through 3D printing, AM is not necessarily the panacea some make it out to be, due to the fact that houses are complex structures that have to do much more than provide a floor, walls and a roof. If adding a floor (or two) on top of the ground floor, additional requirements come into play, before even considering aspects like repairability which is rarely considered in the context of AM construction.
Recently Raspberry Pi released the 2GB version of the Raspberry Pi 5 with a new BCM2712 SoC featuring the D0 stepping. As expected, [Jeff Geerling] got his mitts on one of these boards and ran it through its paces, with positive results. Well, mostly positive results — as the Geekbench test took offence to the mere 2 GB of RAM on the board and consistently ran out of memory by the multi-core Photo Filter test, as feared when we originally reported on this new SBC. Although using swap is an option, this would not have made for a very realistic SoC benchmark, ergo [Jeff] resorted to using sysbenchinstead.
Naturally some overclocking was also performed, to truly push the SoC to its limits. This boosted the clock speed from 2.4 GHz all the way up to 3.5 GHz with the sysbench score increasing from 4155 to 6068. At 3.6 GHz the system wouldn’t boot any more, but [Jeff] figured that delidding the SoC could enable even faster speeds. This procedure also enabled taking a look at the bare D0 stepping die, revealing it to be 32.5% smaller than the previous C1 stepping on presumably the same 16 nm process.
Although 3.5 GHz turns out to be a hard limit for now, the power usage was interesting with idle power being 0.9 watts lower (at 2.4 W) for the D0 stepping and the power and temperatures under load also looked better than the C1 stepping. Even when taking the power savings of half the RAM versus the 4 GB version into account, the D0 stepping seems significantly more optimized. The main question now is when we can expect to see it appear on the 4 and 8 GB versions of the SBC, though the answer there is likely ‘when current C1 stocks run out’.
