Sensing Danger With Spinach

Do you need more proof that we’re living in the future? A group of MIT engineers have found a way for spinach, aka Popeye’s favorite short-term strength booster, to send potentially lifesaving emails regarding explosives in the area.

As the team outlined in a paper published in 2016, the field of plant nanobionics uses nanotechnology to enhance the natural abilities of plants and make them do new tricks. Here’s how this one works: the roots of the spinach plants absorb nitroaromatic compounds such as picric acid from the groundwater, and these transpire up through the stem and into the leaves along with water and other nutrients. When the compounds reach the leaves, they accumulate in the plants’ mesophyll — the inner tissue of the leaves.

A pair of sensors made of single-walled carbon nanotubes are built into the leaves. One sensor is engineered to detect nitroaromatic compounds using near-infrared fluorescent emission, and the other is used as a reference signal. As the the compounds build up in the mesophyll, the IR signal gets stronger. This change is detected by a camera, which triggers an email alert to the researchers within a matter of minutes. After running the experiments with a fancy-pants indium-gallium-arsenide camera, the researchers were able to duplicate the results using a Raspberry Pi and a CCD camera module with the infrared filter removed.

Plants have an ear to the groundwater like none other and absorb a lot of information about the environment around them, so the researchers believe that detecting explosive materials is only the beginning — they could also be harbingers of pollution and other environmental concerns.

Even if there is no threat of landmines in the vicinity, weeds are a problem everywhere. There’s a Raspberry Pi-based solution for those, too.

GBA Gets Homebrew USB Charging Upgrade

Sure there are pre-made kits to add a rechargeable battery and USB-C compatibility to Nintendo’s venerable Game Boy Advance, but [HorstBaerbel] thought he could throw together something similar for a fraction of the price. Plus, he wouldn’t have to wait on shipping. The end result might not be quite as polished, but it’s certainly impressive for what’s essentially a junk bin build.

The star of the show is the popular TP4056 lithium-ion charger module. [HorstBaerbel] went with the more common micro USB version, but these boards are also available with USB-C should you want to embrace the future. The module fits nicely inside the original battery compartment while while still leaving room for a 1,000 mAh pouch cell. The 4.2 V output of the fully charged battery is a bit too high for the Game Boy’s liking, so he used the forward voltage drop of a diode to bring it down to a more acceptable 3.5 V.

Naturally this does waste a good deal of energy, especially compared to the DC-DC converters used in commercial offerings like the CleanJuice, but it still delivers a respectable seven hours of runtime. The only issue with this modification seems to be that you’ve got just five minutes to save your progress and shut down when the GBA’s low-battery light goes on; but what’s life without a little excitement?

While not nearly extreme as some of the other GBA modifications we’ve seen over the years, this project is yet another example of the seemingly unlimited hacking potential of Nintendo’s iconic Game Boy line.

The Future Of Hydrogen Power… Is Paste?

We’ve been promised hydrogen-powered engines for some time now. One downside though is the need for hydrogen vehicles to have heavy high-pressure tanks. While a 700 bar tank and the accompanying fuel cell is acceptable for a city bus or a truck, it becomes problematic with smaller vehicles, especially ones such as scooters or even full-sized motorcycles. The Fraunhofer Institute wants to run smaller vehicles on magnesium hydride in a paste form that they call POWERPASTE.

The idea is that the paste effectively stores hydrogen at normal temperature and pressure, where it stays chemically locked until mixed with water. The researchers note that it will decompose around 250 °C, but while your motorcycle may seem hot when parked in the sun, it isn’t getting quite to 250C.

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PCB Bath Comes From Russia With Love

[Ruvin Kub] likes magnets, a lot. Most of his projects feature some sort of magnet and his PC board agitation bath is no exception. You can see a video about the device, below. We’ll admit our Russian is pretty rusty, but if you ask YouTube nicely it will translate the Russian subtitles into whatever language you like.

One of the things we liked about the video was that he uses hydrogen peroxide, citric acid, and salt as an etchant. We’ve seen the same mix with vinegar or muriatic acid instead of citric acid. We aren’t sure what the actual  translation is about why he doesn’t like ferric chloride, but YouTube says, “she’s too gloomy for my light souls.”

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Cap-Gun Lighter Built From Scratch

For most of us, a lighter is a cheap $2 plastic tool that serves a purpose, and little more. Some of us may go so far as to have a nice Zippo, or perhaps a windproof lighter for better outdoor performance. But if you’re a machinist, you could consider whipping yourself up something special, like this build by [W&M Levsha].

There’s plenty to love here for those who love making chips. The body is crafted out of brass and copper, soldered together by blowtorch. The lighter works by an unusual mechanism. The fluid tank is stuffed with cotton wool and filled with lighter fluid, which feeds a wick, which by itself, is fairly ordinary. However, ignition is via a spring-loaded aluminium hammer, which fires off a paper cap, igniting the wick. The flame can then be extinguished by blowing it out.

It’s a lighter that’s sure to be a conversation piece, though we wonder how welcome it’s cracking report will be at a quiet, reserved cigar bar. The mechanism may have more consumables than a typical lighter, but that’s the price paid to be truly unique. There are other creative designs out there too, like this lighter which uses a platinum catalyst for ignition. Video after the break.

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Super Mario Original Sound Tracks Get High Quality Remaster Thanks To Gigaleak

2020 saw many gigabytes of internal Nintendo data leaked on the broader internet. Known as the “Gigaleak”, it contained source codes and assets from many games. Using data from this leak, a group of enthusiasts has put together high-quality renditions of the SNES Super Mario World Original Sound Tracks (OST).

The work was made possible when source code from the Gameboy Advance remake of Super Mario World was found in the leaked data. The source code included the names of the samples, which were the same as were used in the original SNES game. This allowed the team to find the original samples amongst the gigabytes of leaked files.

We wondered what would be done with all that code, speculating that it would be a poison pill for the emulator scene. This type of hack wasn’t even on our radar and we’re delighted to see the project come to light. The reproduced songs have an altogether different quality than the original SNES soundtrack. This is largely due to the samples not having to be compressed or cut down to fit on a cartridge and work with the console’s sound chip. Other variances in the sound also come from the fact that unlike in the game, the samples in these renditions don’t match the play lengths in the original game.

Regardless of the changes, it’s interesting to hear a more full, rounded sound of these classic video game tunes. It reminds us somewhat of the later CD console era, when sound designers were able to break free of the limitations of earlier hardware. Of course, we still bow at the alter of chiptune, though — and this MIDI Gameboy mod is a great place to start if you’re curious. Video after the break.

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The Right Tools For The Job

We’re knee-deep in new microcontrollers over here, from the new Raspberry Pi Pico to an engineering sample from Espressif that’s right now on our desk. (Spoiler alert, review coming out Monday.) And microcontroller peripherals are a little bit like Pokemon — you’ve just got to catch them all. If a microcontroller doesn’t have 23 UARTS, WiFi, Bluetooth, IR/DA, and a 16-channel 48 MHz ADC, it’s hardly worth considering. More is always better, right?

No, it’s not. Chip design is always a compromise, and who says you’re limited to one microcontroller per project anyway? [Francesco] built a gas-meter reader that reminded to think outside of the single-microcontroller design paradigm. It uses an ATtiny13 for its low power sleep mode, ease of wakeup, and decent ADCs. Pairing this with an ESP8266 that’s turned off except when the ATtiny wants to send data to the network results in a lower power budget than would be achievable with the ESP alone, but still gets his data up into his home-grown cloud.

Of course, there’s more complexity here than a single-micro solution, but the I2C lines between the two chips actually form a natural division of work — each unit can be tested separately. And it’s using each chip for what it’s best at: simple, low-power tasks for the Tiny and wrangling WiFi on the ESP.

Once you’ve moved past the “more is better” mindset, you’ll start to make a mental map of which chips are best for what. The obvious next step is combination designs like this one.