Can you feel the nip of fall in the air? That can only mean one thing: Supercon is just around the corner. The next few weeks are going to bring a blitz of Supercon-related reveals, and we’re starting off with a big one: the workshops.
Using the Moondream visual language model, which runs directly on your Raspberry Pi, and not in the cloud, you can answer questions such as “are the clothes on the line?”, “is there a package on the porch?”, “did I leave the fridge open?”, or “is the dog on the bed?” [Jaryd] compares Moondream to an alternative visual AI system, You Only Look Once (YOLO).
Processing a question with Moondream on your Pi can take anywhere from just a few moments to 90 seconds, depending on the model used and the nature of the question. Moondream comes in two varieties, based on size, one is two billion parameters and the other five hundred million parameters. The larger model is more capable and more accurate, but it has a longer processing time — the fastest possible response time coming in at about 22 to 25 seconds. The smaller model is faster, about 8 to 10 seconds, but as you might expect its results are not as good. Indeed, [Jaryd] says the answers can be infuriatingly bad.
In the write-up, [Jaryd] runs you through how to use Moonbeam on your Pi 5 and the video (embedded below) shows it in action. Fair warning though, Moondream is quite RAM intensive so you will need at least 8 GB of memory in your Pi if you want to play along.
Until the 2000s vacuum tubes practically ruled the roost. Even if they had surrendered practically fully to semiconductor technology like integrated circuits, there was no escaping them in everything from displays to video cameras. Until CMOS sensor technology became practical, proper video cameras used video camera tubes and well into the 2000s you’d generally scoff at those newfangled LC displays as they couldn’t capture the image quality of a decent CRT TV or monitor.
For a while it seemed that LCDs might indeed be just a flash in the pan, as it saw itself competing not just with old-school CRTs, but also its purported successors in the form of SED and FED in particular, while plasma TVs made home cinema go nuts for a long while with sizes, fast response times and black levels worth their high sale prices.
We all know now that LCDs survived, along with the newcomer in OLED displays, but despite this CRTs do not feel like something we truly left behind. Along with a retro computing revival, there’s an increasing level of interest in old-school CRTs to the point where people are actively prowling for used CRTs and the discontent with LCDs and OLED is clear with people longing for futuristic technologies like MicroLED and QD displays to fix all that’s wrong with today’s displays.
Could the return of CRTs be nigh in some kind of format?
A few weeks back, we reported on a research group that figured out how to measure heartrate using perturbations in WiFi signals. [Nick Bild] was interested in this so-called “Pulse-Fi” technique, but noted the paper explaining it was behind a paywall. Thus, he worked to recreate the technology himself so he could publish the results openly for anyone eager to learn.
[Nick] paid for the research paper, and noted that it was short on a few of the finer details and didn’t come with any code or data from the original research team. He thus was left to figure out the finer details of how to measure heart rate via WiFi in his own way, though he believes his method is quite close to the original work.
The basic concept is simple enough. One ESP32 is set up to transmit a stream of Channel State Information packets to another ESP32, with a person standing in between. As the person’s heart beats, it changes the way the radio waves propagate from the transmitting unit to the receiver. These changes can be read from the packets, and processed to estimate the person’s heart rate. [Nick] explains the various data-massaging steps involved to go from this raw radio data to a usable heart rate readout.
Occasionally a design requires capacitors that are much closer to being identical in value to one another than the usual tolerance ranges afford. Precision matching of components from parts on hand might sound like a needle-in-a-haystack problem, but not with [Stephen Woodward]’s Capacitor Matchmaker design.
The larger the output voltage, the greater the mismatch between capacitors A and B.
The Matchmaker is a small circuit intended to be attached to a DVM, with the output voltage indicating whether two capacitors (A and B) are precisely matched in value. If they are not equal, the voltage output indicates the degree of the mismatch as well as which is the larger of the two.
The core of the design is complementary excitation of the two capacitors (the CD4013B dual flip-flop achieves this) which results in a measurable signal if the two capacitors are different; nominally 50 mV per % of mismatch. Output polarity indicates which of the capacitors is the larger one. In the case of the two capacitors being equal, the charges cancel out.
Can’t precision-matched capacitors be purchased? Absolutely, but doing so is not always an option. As [Stephen] points out, selection of such components is limited and they come at an added cost. If one’s design requires extra-tight tolerances, requires capacitor values or types not easily available as precision pairs, or one’s budget simply doesn’t allow for the added cost, then the DIY approach makes a lot more sense.
If you’re going to go down this road, [Stephen] shares an extra time-saving tip: use insulated gloves to handle the capacitors being tested. Heating up a capacitor before testing it — even just from one’s fingers — can have a measurable effect.
[Stephen]’s got a knack for insightful electronic applications. Check out his PWMPot, a simple DIY circuit that can be an awfully good stand-in for a digital potentiometer.
What do you do when you find a ISA Sound Blaster 2.0 card in a pile of scrap? Try to repair the damage on it to give it a second shot at life, of course. This is what [Adrian Black] did with one hapless victim, with the card in question being mostly in good condition minus an IC that had been rather rudely removed. The core Creative CT1336A and Yamaha YM3812 ICs were still in place, so the task was to figure out what IC was missing, find a replacement and install it.
The CT1350 is the final revision of the original 8-bit ISA Sound Blaster card, with a number of upgrades that makes this actually quite a desirable soundcard. The CT1350B revision featured here on a card from 1994 was the last to retain compatibility with the C/MS chips featured on the original SB card. After consulting with [Alex] from the Bits und Bolts YT channel, it was found that not only is the missing IC merely an Intel 8051-based Atmel MCU, but replacements are readily available. After [Alex] sent him a few replacements with two versions of the firmware preflashed, all [Adrian] had to do was install one.
Before installation, [Adrian] tested the card to see whether the expected remaining functionality like the basic OPL2 soundchip worked, which was the case. Installing the new MCU got somewhat hairy as multiple damaged pads and traces were discovered, probably because the old chip was violently removed. Along the way of figuring out how important these damaged pads are, a reverse-engineered schematic of the card was discovered, which was super helpful.
Some awkward soldering later, the card’s Sound Blaster functionality sprung back to life, after nudging the volume dial on the card up from zero. Clearly the missing MCU was the only major issue with the card, along with the missing IO bracket, for which a replacement was printed after the video was recorded.
Usually when an alchemist shows up promising to turn rocks into gold, you should run the other way. Sure, rocket fuel isn’t gold, but on the moon it’s worth more than its weight in the yellow stuff. So there would be reason to be skeptical if this “Blue Alchemist” was actually an alchemist, and not a chemical reactor under development by the Blue Origin corporation.
The chemistry in question is quite simple, really: take moon dust, which is rich in aluminum silicate minerals, and melt the stuff. Then it’s just a matter of electrolysis to split the elements, collecting the gaseous oxygen for use in your rockets. So: moon dust to air and metals, just add power. Lots and lots of power.
Melting rock takes a lot of temperature, and the molten rock doesn’t electrolyse quite as easily as the water we’re more familiar with splitting. Still, it’s very doable; this is how aluminum is produced on Earth, though notably not from the sorts of minerals you find in moon dust. Given the image accompanying the press release, perhaps on the moon the old expression will be modified to “make oxygen while the sun shines”.
That’s not likely to be flying any time soon, but of course even with the Methalox rockets in vogue these days, there are appreciable cost savings to leaving your oxygen and home. And we’re not biologists, but maybe Astronauts would like to breathe some of this oxygen stuff? We’ve heard it’s good for your health.
