How do you collect a lot of data about the ionosphere? Well, you could use sounding rockets or specialized gear. Or maybe you can just conscript a huge number of cell phones. That was the approach taken by Google researchers in a recent paper in Nature.
The idea is that GPS and similar navigation satellites measure transit time of the satellite signal, but the ionosphere alters the propagation of those signals. In fact, this effect is one of the major sources of error in GPS navigation. Most receivers have an 8-parameter model of the ionosphere that reduces that error by about 50%.
However, by measuring the difference in time between signals of different frequencies, the phone can estimate the total electron current (TEC) of the ionosphere between the receiver and the satellite. This requires a dual-frequency receiver, of course.
The Raspberry Pi 5 board strapped to a liquid nitrogen cooler with an ElmorLabs AMPLE-X1 power board attached. (Credit: Pieter-Jan Plaisier, SkatterBencher.com)
As impractical as most overclocking of computers is these days, there is still a lot of fun to be had along the way. Case in point being [Pieter-Jan Plaisier]’s recent liquid nitrogen-aided overclocking of an unsuspecting Raspberry Pi 5 and its BCM2712 SoC. Previous OCing attempts with air cooling by [Pieter] had left things off at a paltry 3 GHz from the default 2.4 GHz, with the power management IC (PMIC) circuitry on the SBC turning out to be the main limiting factor.
The main change here was thus to go for liquid nitrogen (LN2) cooling, with a small chipset LN2 pot to fit on the SBC. Another improvement was the application of a NUMA (non-uniform memory addressing) patch to force the BCM2712’s memory controller to utilize better RAM chip parallelism.
With these changes, the OC could now hit 3.6 GHz, but at 3.7 GHz, the system would always crash. It was time to further investigate the PMIC issues.
The PMIC imposes voltage configuration limitations and turns the system off at high power consumption levels. A solution there was to replace said circuitry with an ElmorLabs AMPLE-X1 power supply and definitively void the SBC’s warranty. This involves removing inductors and removing solder mask to attach the external power wires. Yet even with these changes, the SoC frequency had trouble scaling, which is why an external clock board was used to replace the 54 MHz oscillator on the PCB. Unfortunately, this also failed to improve the final overclock.
We covered the ease of OCing to 3 GHz previously, and no doubt some of us are wondering whether the new SoC stepping may OC better. Regardless, if you want to get a faster small system without jumping through all those hoops, there are definitely better (and cheaper) options. But you do miss out on the fun of refilling the LN2 pot every couple of minutes.
According to the Sapir–Whorf hypothesis, our language influences how we think and experience the world. That’s easy to imagine. Certainly our symbolism of mathematics influences how we calculate. Can you imagine doing moderately complex math with Roman numerals or without zero or negative numbers? But recently I was reminded that technological media also influences our perception of reality, and I have a Hackaday post to thank for it.
The post in question was about color TV. When I was a kid, most people had black and white TVs, although there were color sets. Even if you had a color set, many shows and movies were in black and white. Back then, many people still shot black and white film in their cameras, too, for many reasons. To make matters worse, I grew up in a small town, reading books from the local library that were ten or twenty years behind the times.
At some point, I read a statistic that said that most people dream in black and white. You may find this surprising, as I’ll bet you dream in color. It turns out, how people dream may have changed over the years and still and motion photography may be the reason.
The Post
In the post, I posed a question I’ve thought about many times: Did people dream in black and white before the advent of photography? It was kind of an off-hand remark to open the post, but many people reacted to it in the comments. They seemed surprised that I would ask that because, of course, everyone dreams in color.
I asked a few people I knew who also seemed very surprised that I would assume anyone ever dreams in color. But I was sure I had been told that sometime in the past. Time to hit the Internet and find out if that was incorrect or a false memory or something else. Turns out, it was indeed something else.
A scientific paper from 2008 held the answer. It turns out that science started asking questions like this in the early 1900s. Up through the 1940s, people overwhelmingly reported dreaming in black and white, at least most of the time. Color dreams were in the minority, although not unheard of.
Then something changed. Studies that occurred in the 1960s and later, show exactly the opposite. People almost always dream in color and rarely in black and white. Of course, that correlates well with the rise of color photos, movies, and television. What’s more is, while there is no scientific evidence gathering about earlier times, there is a suspicious lack of, for example, a Shakespeare quote about “The gray world of slumber…” or anything else that would hint that the writer was dreaming in black and white.
Interpretation
Judging from the paper, it seems clear that most people agree that color media played a role in this surprising finding. What they can’t agree on is why. It does seem unlikely that your dreams really change based on your media consumption. But it is possible that your recollection changes. This is particularly true since the way researchers acquired data changed over that time period, too. But even if the data doesn’t show that you dreamed in black and white, it did show that you remembered dreaming in black and white.
For that matter, it isn’t clear that anyone understands how you experience dreams visually, anyway. It isn’t like the back of your eyelids are little movie screens. You don’t actually see anything in a dream, you only remember seeing it.
The Question
If something as simple as black-and-white movies and TV can change how we perceive dreams, you have to wonder how much tech is changing our reality experience in other ways. Do we live differently because we have cell phones? Or the Internet? Will virtual reality alter our dream lives? It would be interesting to fast-forward a century and see what historians say about our time and how strangely we perceive reality today.
Early computer kits aimed at learning took all sorts of forms, from full-fledged computer kits like the Altair 8800 to the ready-made MicroBee Computer-In-A-Book. For those just wanting to dip their toes in the computing world, many low-cost computer “trainers” were released, and Japan had some awesome ones. [Jason Jacques] shows off his Gakken Micro-Computer FX-System (or is it the FX-Computer? Or maybe the FX-Micom? It seems like they couldn’t make up their minds). In any event, it was a combination microcomputer and I/O building blocks system running a custom version of the Texas Instrument TMS1100 microprocessor. Specifically designed to introduce users to the world of computing, the included guide is very detailed and includes 100 example programs and lots of information on how all the opcodes work.
This 4-bit system is similar to the Kenbak computer, with a very simple instruction set and limited address space. However, adding electronic components in plastic blocks brings this machine to a new level of interactivity. Connections can be made to and from the microcomputer block, as well as to the on-board speaker and simple input/output pins. The example circuit displayed on the front cover of the box enables the microcontroller to connect to the speaker and allows a switch to light up a small incandescent bulb. We can imagine many users wiring up all sorts of extra components to their FX-Computers, and with the advent of 3D printing, it wouldn’t be difficult to create new blocks to insert into the grid.
Ceci n’est pas unekeyboard, sure. But it’s keyboard-adjacent, and how. [Joshua Bemenderfer]’s wrists are tired of moving off the keyboard in order to mouse, and he decided to create a trackball that can sit just below the Space bar. The idea is to get rid of the regular mouse entirely if this works out.
Image by [Joshua Bemenderfer] via Hackaday.IOAnd sure, the Ploopy family of open-source mice would welcome him with open arms, but they don’t come cheap. [Joshua]’s plan here is to make something for under $10. Ideally, less than $5.
Starting with an off-the-shelf trackball, the first BOM came in around $25 if you throw in $5 for the 3D printing of the case. [Joshua] added some cheap ceramic bearings to make it better. Since this was still too high, he turned to the internals of cheap mice.
Trial and error has resulted in a 99-cent special from Ali being the idea candidate. There are even cheaper mice to be had, but this one has an ideal layout for doing a bit of surgery. It also requires remapping since [Joshua] is flipping the sensor upside down and using a POM ball on top of it. Now he just needs to figure out how to add buttons and make them split keyboard-friendly.
Normally, you think of things casting a shadow as being opaque. However, new research shows that under certain conditions, a laser beam can cast a shadow. This may sound like nothing more than a novelty, but it may have applications in using one laser beam to control another. If you want more details, you can read the actual paper online.
Typically, light passes through light without having an effect. But using a ruby crystal and specific laser wavelengths. In particular, a green laser has a non-linear response in the crystal that causes a shadow in a blue laser passing through the same crystal.
Collecting retrocomputers is fun, especially when you find fully-functional examples that you can plug in, switch on, and start playing with. Meanwhile, others prefer to find the damaged examples and nurse them back to health. [polymatt] can count himself in that category, as evidenced by his heroic rescue of an 1993 IBM ThinkPad Tablet.
The tablet came to [polymatt] in truly awful condition. Having been dropped at least once, the LCD screen was cracked, the case battered, and all the plastics were very much the worse for wear. Many of us would consider it too far gone, especially considering that replacement parts for such an item are virtually unobtainable. And yet, [polymatt] took on the challenge nonetheless.
Despite its condition, there were some signs of life in the machine. The pen-based touch display seemed to respond to the pen itself, and the backlight sort of worked, too. Still, with the LCD so badly damaged, it had to be replaced. Boggling the mind, [polymatt] was actually able to find a 9.4″ dual-scan monochrome LCD that was close enough to sort-of fit, size-wise. To make it work, though, it needed a completely custom mount to fit with the original case and electromagnetic digitizes sheet. From there, there was plenty more to do—recapping, recabling, fixing the batteries, and repairing the enclosure including a fresh set of nice decals.
The fact is, 1993 IBM ThinkPad Tablets just don’t come along every day. These rare specimens are absolutely worth this sort of heroic restoration effort if you do happen to score one on the retro market. Video after the break.
