Going Whole-Hog On A First Satellite Ground Station

October 20, 2026 by No comments

When most radio enthusiasts start trying to pick up signals from satellites, they might put together a quick-and-dirty Yagi antenna and try to catch a repeater as is passes overhead, or they might grab a small unused dish from a satellite TV service and point it up at a weather satellite by hand to try to decode some of the data coming down. But [Cranktown City] had a different approach. He found an eight-foot dish online and built a massive articulating base station out of it as his first exploration into the world of satellites.

The first problem that needs to be solved with a dish of this size is its mounting location. This installation uses a large post and concrete foundation with a custom-fabricated metal base at the bottom. The metal base houses all of the electronics not just for receiving signals from the dish, but also for orienting it properly. That includes a large metal gear driven by a wheelchair motor to control its azimuth and a linear actuator to take care of its elevation. Getting the large dish onto the frame was its own ordeal, complicated by the fact that it’s not uniform in its shape and has to be mounted in a specific orientation.

With everything assembled, the circularly-polarized antenna installed, and the computers up and running, the dish is able to track satellites across the sky and download data from things like GOES weather satellites. [Cranktown City] also built in a system that detects wind and points the dish vertically when it goes above a certain speed. This level of effort is impressive, and absolutely not required to listen in on plenty of sattelite activity out in the sky, but this installation will certainly give [Cranktown City] a lot of mileage and possibly even work for some radio astronomy.

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NASA’s Lunar Grounding Challenge Is A Real Buzz

October 20, 2026 by 3 Comments

One could make a joke about how an astronaut walking on the lunar surface is rather akin to a cat walking on the carpet in the living room, but out in space the resulting triboelectric discharge can do a lot more damage than just some stinging fingers and a bemused looking cat.

The problem that NASA and other space agencies are dealing with is that the charge that builds up on a lunar-walking astronaut is very hard to equalize with something like a lunar lander. For this reason they have now set up the Lunar Grounding Challenge to consult the public whilst dangling $150,000 of rewards in front of anyone ready to pounce with a good idea.

Here on Earth we got many ways in which we can get rid of such an unwanted charge, with dry winter weather demonstrating quite effectively why humidity is a crucial factor here. With no real atmosphere on the Moon, each astronaut thus becomes a walking capacitor, which is worsened when said astronaut ventures outside of the sunlit areas and then returns to the slightly positively charged lander.

The challenge here is thus to equalize the astronaut and lander, with a design specification of a -100 kV or higher astronaut and about 100 V lander. A resulting current should not exceed 1 mA, ideally less than 0.2 mA to remain below human perception levels. If an arc exists it should not contact the suit or astronaut.

Of course, the most low-tech solution would be to use a resistor to limit the current, but at those voltage ranges it would take an awful long time to bleed off, in an environment that’s basically a perfect insulator as space will never be cold. It definitely seems like a fun challenge to sink one’s fangs into.

A series of ten close up images of two pieces of coral. In the first, on the top left, the coral on the left is bright white while the one on the right is brown with darker brown spots. Text reads: "Week 0." The last image, on the bottom right, shows both pieces of coral as brown with darker brown spots and the text, "Week 9." The intervening images show the white, dead coral, slowly becoming more brown as time progresses.

Spreading Life To Bleached Coral

October 20, 2026 by 4 Comments

Coral bleaching is a major problem for ocean ecosystems as the ocean gets warmer. Researchers at Stanford have found a new method for regenerating bleached corals.

Scientists working on coral found that when they had a bleached and healthy example accidentally touching in the lab, the symbionts from the healthy coral that make its food were able to spread to the bleached coral, reviving it in a matter of weeks. Contact was only required for one week, although three days was sufficient in a few cases. The effect only seems to work with corals of the same genet as the healthy corals of other genets just take over the bleached coral antagonistically.

This is particularly exciting, as areas where not all coral has bleached may indicate the presence of symbionts that are more heat tolerant, and being able to spread these symbionts to their neighbors quickly can greatly speed up the process of coral regeneration and save the reef. Coral reefs are some of the most vibrant ecosystems in the ocean, so if you save the coral, you can save many other species as well that rely on them.

If you’d like to explore how the coral is doing near you, perhaps you should try an open ROV or a bionic jellyfish?

Super Mario Galaxy Now Runs On The GBA

October 20, 2026 by No comments

Joining the ranks of fresh backported Nintendo games is Super Mario Galaxy for the Nintendo Game Boy Advance (GBA), courtesy of [Tobias Friedly], AKA [Tobi]. In a recent video he announces the release of this game, along with the release of the source code of the engine and all the game’s code in a GitHub project.

Naturally none of the original Wii game’s assets are provided to appease Nintendo’s vicious lawyers, so you’re expected to bring your own super-legally acquired ISO image or equivalent to fill in these blanks when you build your ROM for the GBA.

This is a mostly complete port, even integrating the star pointer despite the GBA’s limited number of controls compared to the Wii. In some situations it’s opted to have star bits automatically collected to work around this limitation, which is probably a quality-of-life improvement that many SMG players will appreciate.

For the game’s logic a lot of code was borrowed from the recently decompiled version of the original game, which saved a lot of time even if the GBA’s hardware is no match for the Wii’s. From the gameplay in the video it definitely looks like a playable version of the game, with an acceptable frame rate that looks to be worth a try.

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Visualize Regular Expressions With Marbles

October 20, 2026 by 14 Comments

If you are one of those people who visualize things physically better than in the abstract, then Regex Marble Run by [bottomless] might be for you. You enter a test expression and a string, and the site generates a virtual marble machine that lets you see the regular expression pick apart the string in a physical way.

Click this link, and you’ll see the regular expression “^[hH]ack.[dD][^0-9]*$” which, if you aren’t a regular expression user, might seem a bit cryptic. However, it is fairly simple if you take it bit-by-bit.

The caret character tells it to match the start of the string. So “^dog” will match “dog” and “dog food” but won’t match “food for a dog.” The following bit “[hH]” will match either “h” or “H”. Then there is “ack” which is just what you think it is. So a string starting with “hack” or “Hack” might match (depending on the rest of the expression.

The period means match any single character. Then there’s another “[]” but this time with “dD” to match any kind of D. The next “[]” character class is a range from 0-9, but since there is a caret, the match is negated. So “[^0-9]” means match anything except a digit from 0 to 9. The “*” means we can have zero or more of these. So “HackxD” matches, but so does “HackxDXYZabc” for now. Trick question: Does “HackxDXYZabc123” match? So far, yes, but it only matches to the lowercase “c” character.

The final character, “$” means end of string. So now “HackxDXYZabc123” does not match because we are still in the middle of the string. However, “HackxDXYZabc” will match since the previous “*” “ate” the rest of the string.

Head spinning? The site will let you see each letter of a test string as a marble that falls through the different parts of the regular expression. Balls that pass wind up in the left-hand box, while failures are in the right-hand box. Will it help you? We don’t know, but it is fun to watch.

Want a refresher on regular expressions? Or perhaps you want some practice?

Birduino Plays Bird Calls On Demand With NFC-enabled Cards

October 19, 2026 by 7 Comments

All [Hannah Robertson]’s Birduino needs is for one to tap an NFC-enabled card to the reader, and the device plays one of the vocalizations associated with the bird shown on the card. It ties together a few different components into a whole, and acts as a good reference design for similar work. There are a few time-saving construction tips worth keeping in mind, too.

The major components are an Arduino Nano, an RC522 RFID reader, and an MP3 player module. Using hardware modules and breakout boards means simpler wiring and being able to take advantage of existing libraries and sample code. There are also a few other things in this build that avoid re-inventing the wheel.

A deck of bird cards plus a roll of NFC stickers equals a ready-to-scan assortment without having to design it oneself.

Rather than design, print, and cut a set of bird cards, [Hannah] found a set of bird-themed playing cards with a different North American bird on each. The back of each card gets an NFC sticker off a big roll purchased online. The result? A set of NFC-enabled bird cards with a minimum of work and fuss. The RC522 RFID reader doesn’t fully support NFC, but it works well enough to read the ID off the stickers.

When the user touches a card to the reader, the device plays one of the vocalizations from a collection of sounds for each bird. Creating the manifests and linking each card’s ID to them was a lot of manual work, but the result is great. The sound themselves come from the Cornell Guide to Bird Sounds of the United States and Canada, a $20 USD curated compilation of vocalizations from a staggering 908 bird species of North America. In a way, the biggest bottleneck is the card deck itself. At 52 cards plus two Jokers, it contains only a small subset of the total birds in the Cornell collection.

The enclosure is laser-cut clear acrylic, and here [Hannah] offers some time- and money-saving advice for anyone looking to glue acrylic to acrylic in a way that doesn’t frost or cloud the clear acrylic: Clear Gorilla Glue Gel. There are of course other glues made for this purpose, but Clear Gorilla Glue Gel (the one in a squeeze tube) is something one should be able to find in just about any hardware store. Another tip: double-check before buying, because many Gorilla Glue products are very similarly named despite being significantly different products.

Watch (and listen to) the video embedded below. If birds and their vocalizations are something that intrigues and inspires you, Cornell also has a resource for identifying birds by sound alone — we’ve seen it implemented with a Raspberry Pi and USB microphone.

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Making Photovoltaic Solar Cells With A Microwave

October 19, 2026 by 2 Comments

Although solar panels may seem like a kind of magic, they’re really quite simple devices, in their silicon form featuring nothing but the p-type silicon wafer and an n-type layer doped with e.g. phosphorus. Because of this simplicity it’s quite possible to make your own solar cells at home using only a few basic, off-the-shelf ingredients and a kiln, which in this recent video by [Dr. Semiconductor] uses a microwave kiln and thus justifies the video’s title.

Even the silicon wafer that you start with can be easily purchased online, though you have to be careful that it’s a bare wafer, without existing etchings on it. On this you need to get a phosphorus-rich layer, which is done by creating a delicious mixture of 1 mL of tetraethyl orthosilicate (TEOS), 0.3 mL of 85 wt% phosphoric acid, 5 mL of ethanol and 0.25 mL of distilled water. After low heat boiling this for 30 minutes, it is spincoated onto the cut square of silicon wafer using a spinning platform, like a PC fan.

Next, you shove the coated silicon into the kiln and put it into the microwave to bake at a fairly low power level for half an hour. In the video it took less than 50% power of the microwave to not melt the silicon, so remember that those microwave kilns get pretty hot.

With the delightful smells of freshly baked silicon now teasing your nostrils, you can then take out the doped silicon to sand or etch off the thin layer of glass that’s formed around the new PV cell. On the clear spots you can now put a gallium-indium contact on the p-type Si side and a wad of indium on the newly doped Si-P side, which are now your contacts for the PV cell.

The full recipe along with many of the issues discussed in the video can also be found on the blog article, though the video conclusion notes that many improvements are still possible. The created PV cell in the video reaches an efficiency of about 5%, but this could be improved through changes like the use of a clean-room, adding an anti-reflection coating and improving the contact with the cell.

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