Access To Fresh And Potable Water: An Ancient And Very Current Challenge

July 2, 2024 by Maya Posch 28 Comments

Throughout history, clean and potable water has been one of the most prized possessions, without which no human civilization could have ever sustained itself. Not only is water crucial for drinking and food preparation, but also for agriculture, cleaning and the production of countless materials, chemicals and much more. And this isn’t a modern problem: good water supplies and the most successful ancient cultures go hand in hand.

For instance, the retention and management of fresh water in reservoirs played a major role in the Khmer Empire, with many of its reservoirs (baray) surviving to today. Similarly, the Anuradhapure Kingdom in Ceylon (now Sri Lanka) featured massive reservoirs like Kala Wewa that was constructed in 460 CE with a capacity of 123 million m³. In the New World, the Maya civilization similarly created reservoirs with intricate canals to capture rainwater before the dry season started, as due to the karst landscape wells were not possible.

Keeping this water fresh and free from contaminants and pollution was a major problem for especially the Maya, with a recent perspective by Lisa J. Lucera in PNAS Anthropology suggesting that they used an approach similar to modern day constructed wetlands to keep disease and illness at bay, while earlier discoveries also suggest the use of filtration including the use of zeolite.

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SIMD-Accelerated Computer Vision On The ESP32-S3

July 1, 2024 by Maya Posch 11 Comments

One of the fun parts of the ESP32-S3 microcontroller is that it got upgraded to the newer Cadence Xtensa LX7 processor core, which turns out to have a range of SIMD instructions that can help to significantly speed up a range of tasks. [Shranav Palakurthi] recently used this to speed up the processing of video frames to detect corners using the FAST method. By moving some operations that benefit from SIMD over to an optimized version written in LX7 ASM, the algorithm’s throughput was increased by 220%, from 5.1 MP/s to 11.2 MP/s, albeit with some caveats.

The problem with the SIMD instructions in the LX7 other than them being very poorly documented – unless you sign an NDA with Cadence – is that it misses many instructions that would be really useful. For [Shranav] the lack of support for direct misaligned reads and comparing of unsigned 8-bit numbers were hurdles, but could be worked around, with the results available on GitHub.

Much of the groundwork for this SIMD implementation was laid by [Larry Bank], who reverse-engineered the SIMD instructions from available documentation and code samples, finding that the ESP32-S3 misses quite a few common SIMD instructions, including various shifts and unaligned reads and writes. Still, it’s good enough for quite a few tasks, as long as you can make it work with the available instructions.

By kallerna - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=122952945

ChatGPT And Other LLMs Produce Bull Excrement, Not Hallucinations

July 1, 2024 by Maya Posch 99 Comments

In the communications surrounding LLMs and popular interfaces like ChatGPT the term ‘hallucination’ is often used to reference false statements made in the output of these models. This infers that there is some coherency and an attempt by the LLM to be both cognizant of the truth, while also suffering moments of (mild) insanity. The LLM thus effectively is treated like a young child or a person suffering from disorders like Alzheimer’s, giving it agency in the process. That this is utter nonsense and patently incorrect is the subject of a treatise by [Michael Townsen Hicks] and colleagues, as published in Ethics and Information Technology.

Much of the distinction lies in the difference between a lie and bullshit, as so eloquently described in [Harry G. Frankfurt]’s 1986 essay and 2005 book On Bullshit. Whereas a lie is intended to deceive and cover up the truth, bullshitting is done with no regard for, or connection with, the truth. The bullshitting is only intended to serve the immediate situation, reminiscent of the worst of sound bite culture.

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Apple May Use Electrical Debonding For Battery Replacement

June 29, 2024 by Maya Posch 21 Comments

As a result of the European Union’s push for greater repairability of consumer devices like smartphones, Apple sees itself forced to make the batteries in the iPhone user-replaceable by 2027. Reportedly, this has led Apple to look at using electroadhesion rather than conventional adhesives which require either heat, isopropyl alcohol, violence, or all of the above to release. Although details are scarce, it seems that the general idea would be that the battery is wrapped in metal, which, together with the inside of the metal case, would allow for the creation of a cationic/anionic pair capable of permanent adhesion with the application of a low-voltage DC current.

This is not an entirely wild idea. Tesa has already commercialized it in the electrical debonding form of its Debonding on Demand product. This uses a tape that’s applied to one side of the (metal) surfaces, with a 5 bar pressure being applied for 5 seconds. Afterwards, the two parts can be released again without residue as shown in the above image. This involves applying a 12V DC voltage for 60 seconds, with the two parts afterward removable without force.

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Building A Hydraulic System With 3D Printed SLA Resin Parts

June 29, 2024 by Maya Posch 3 Comments

Showing off the 3D-printed hydraulics system. (Credit: Indeterminate Design, YouTube)

Hydraulics are incredibly versatile, but due to the pressures at which they operate, they are also rather expensive and not very DIY-friendly. This isn’t to say that you cannot take a fair shot at a halfway usable 3D-printed set of hydraulics, as [Indeterminate Design] demonstrates in a recent video. Although not 100% 3D-printed, it does give a good idea of how far you can push plastic-based additive manufacturing in this field.

Most interesting is the integration of the gear pump, 4-way selector valve, and relief valve into a single structure, which was printed with a resin printer (via the JLC3DP 3D print service). After bolting on the (also 3D printed) clear reservoir and assembling the rest of the structure including the MR63 ball bearings, relief spring valve, and pneumatic fittings it was ready to be tested. The (unloaded) gear pump could pump about 0.32 L/minute, demonstrating its basic functionality.

For the hydraulic cylinder, mostly non-3D printed parts were used, with a brass cylinder forming the main body. During these initial tests, plain water was used, followed by CHF11 hydraulic oil, with a pressure of about 1.3 bar (19 PSI) calculated afterward. This fairly low pressure is suspected to be caused by leaky seals (including the busted shaft seal), but as a basic proof of concept, it provides an interesting foundation for improvements.

Want a primer on hydraulics? We got you. MIT likes 3D printing with hydraulics, too (dead link, but the underlying paper link is still good).

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Reviving A Free 1990s Millport CNC Vertical Mill

June 28, 2024 by Maya Posch 25 Comments

When faced with the offer of free machining equipment, there is no realistic way to say ‘no’. This is how [Anthony Kouttron]’s brother [Thomas] got to pick up a large 1990s-era CNC machine as a new companion for his growing collection of such equipment. The trickiest part of the move to the new location was getting the machine to fit through the barn doors, requiring some impromptu disassembly of the Z-axis assembly, which required the use of an engine crane and some fine adjustments with the reinstallation. With that [Thomas] and [Anthony] got to gawk at their new prize in its new home.

This Millport vertical mill is effectively a Taiwanese clone of the Bridgeport vertical mill design, though using an imported servo control system from Anilam. The most exciting part about a CNC machine like this is usually the electronics, especially for a well-used machine. Fortunately the AT-style PC and expansion cards looked to be in decent condition, and the mill’s CRT-based controller popped up the AMI BIOS screen before booting into the Anilam S1100 CNC software on top of MS-DOS, all running off a 1 MB Flash card.

Which is not to say that there weren’t some issues to be fixed. The Dallas DS12887 real-time clock/NVRAM module on the mainboard was of course dead. After replacing it, the BIOS finally remembered the right boot and input settings, so that the CNC machine’s own controls could be used instead of an external keyboard. This just left figuring out the Anilam controls, or so they thought, as a range of new errors popped up about X-lag and the Distribution Board. This had [Anthony] do a deep-dive into the electronics cabinets to clean metal chips and repair broken parts and floating pins. After this and a replacement Anilam Encoder this Millport vertical mill was finally ready to be put back into service.

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Cleaning Up World War 2’s Legacy On The Seafloor With Robots

June 28, 2024 by Maya Posch 26 Comments

Until the 1970s, a very common method to dispose of unneeded munitions was to simply tip them off the side of a ship. This means that everything from grenades to chemical weapons have been languishing in large quantities around Europe’s shorelines, right alongside other types of unexploded ordnance (UXO).

Although clearing and mapping such dump sites are a standard part of e.g. marine infrastructure such as undersea cabling and off-shore wind turbines, no large-scale effort has so far been undertaken to remove them, even as they continue to pose an increasing hazard to people and the environment. Most recently, efforts are underway to truly begin clearing these UXO, as the BBC reports.

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