The Moondrop MIAD 01: A Smartphone With Balanced Audio Output

May 9, 2024 by Maya Posch 1 Comment

Over the past several years we have seen smartphones regrettably lose features which were once standard, such as FM radios, IR blasters, status LEDs, physical buttons, micro SD card slots, and of course headphone jacks. An interesting counterpoint here regarding the latter is the newly released Moondrop MIAD 01 smartphone.

As a relatively well-known manufacturer of audio equipment including in-ear monitors (IEMs), the announcement of a smartphone came out of left field, but the specifications make sense. Of particular interest are the dual audio jacks: one 3.5 mm TRRS and one 4.4 mm balanced TRRS, making it a good match for high-end headphones that support balanced audio.

While the smartphone hardware is your average mid-range selection, featuring a MediaTek Dimensity 7050 SoC — its main selling point are the dual Cirrus Logic MasterHiFi DACs, that power the dual audio jacks. It’s also the reason behind the name: Mobile Internet Audio Device, or MIAD for short.

Given Moondrop’s audio enthusiast market, this tracks. These are people for whom the mere mentioning of ‘Bluetooth Audio’ or ‘USB-C-to-audio jack dongle’ is likely to evoke a less than favorable response.

In terms of software, Moondrop says the phone will offer a “native” Android 13 experience, which hopefully means it will be free from manufacturer-specific changes and bloatware. You’ll need to manually install Google Mobile Services though, as is often the case with Android devices that aren’t from the major players in the industry.

As reported by Android Authority, the MIAD 01 is available via select outlets for $399. Details like software updates remain to be clarified, but this might be the most over the top audio-centric smartphone we have seen so far. It definitely gives Sony’s current range of Android-based Walkmans a run for their money, while even having phone functionality in the package.

Matchbox Transceiver Pushes The Spy Radio Concept To Its Limits

May 9, 2024 by Dan Maloney 3 Comments

The Altoids tin has long been the enclosure of choice for those seeking to show off their miniaturization chops. This is especially true for amateur radio homebrewers — you really have to know what you’re doing to stuff a complete radio in a tiny tin. But when you can build an entire 80-meter transceiver in a matchbox, that’s a whole other level of DIY prowess.

It’s no surprise that this one comes to us from [Helge Fykse (LA6NCA)], who has used the aforementioned Altoids tin to build an impressive range of “spy radios” in both vacuum tube and solid-state versions. He wisely chose solid-state for the matchbox version of the transceiver, using just three transistors and a dual op-amp in a DIP-8 package. There’s also an RF mixer in an SMD package; [Helge] doesn’t specify the parts, but it looks like it might be from Mini-Circuits. Everything is mounted dead bug style on tiny pieces of copper-clad board that get soldered to a board just the right size to fit in a matchbox.

A 9 volt battery, riding in a separate matchbox, powers the rig. As do the earbud and tiny Morse key. That doesn’t detract from the build at all, and neither does the fact that the half-wave dipole antenna is disguised as a roll of fishing line. [Helge]’s demo of the radio is impressive too. The antenna is set up very low to the ground to take advantage of near vertical incidence skywave (NVIS) propagation, which tends to direct signals straight up into the ionosphere and scatter them almost directly back down. This allows for medium-range contacts like [Helge]’s 239 km contact in the video below.

Banging out Morse with no sidetone was a challenge, but it’s a small price to pay for such a cool build. We’re not sure how much smaller [Helge] can go, but we’re eager to see him try.

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ArdEEG Lowers The Cost Of Brain-Computer Interfaces

May 8, 2024 by Tom Nardi 3 Comments

Considering the incredible potential offered by brain-computer interfaces (BCIs), it’s no wonder there are so many companies scrambling to make their mark in the field. Some see it as an assistive technology, while others imagine it as the future of interactive entertainment. Regardless of the application, the technology has yet to make much inroads with the DIY crowd — largely due to the complexity and cost of the hardware involved.

But that might change in the near future thanks to projects like ardEEG from [Ildar Rakhmatulin]. This open source shield mounts to the top of the Arduino UNO R4 WiFi and features eight channels for collecting electroencephalogram (EEG) data, such as from a dry electrode cap. The signals can then be processed on the computer using the provided Python example code. From there, the raw data can be visualized or plugged into whatever application you have in mind.

Why target the relatively uncommon WiFi version of the Uno? It’s probably obvious for those with experience with this kind of hardware, but for safety, the system needs complete electrical isolation. The Arduino and shield are powered by a common USB battery bank, and all communication is done over WiFi. Even still, the documentation is clear that the ardEEG is not a medical device, and hasn’t been certified by any regulatory agency — its use is entirely at your own risk.

[Ildar] tells us the hardware will be available soon and should cost under $250, making it one of the most affordable BCI development platforms out there. As with his earlier PiEEG project, the hope is that basing the system around a common device in the hacker and maker scene will help democratize access to BCI research.

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How We Got The Scanning Electron Microscope

May 8, 2024 by Al Williams 2 Comments

According to [Asianometry], no one believed in the scanning electron microscope. No one, that is, except [Charles Oatley].The video below tells the whole story.

The Cambridge graduate built radios during World War II and then joined Cambridge as a lecturer once the conflict was over. [Hans Busch] demonstrated using magnets to move electron beams, which suggested the possibility of creating a lens, and it was an obvious thought to make a microscope that uses electrons.

After all, electrons can have smaller wavelength than light, so a microscope using electrons could — in theory — image at a higher resolution. [Max Knoll] and [Ernst Ruska], in fact, developed the transmission electron microscope or TEM.

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FLOSS Weekly Episode 782: Nitric — In Search Of The Right Knob

May 8, 2024 by Jonathan Bennett No comments

This week Jonathan Bennett and David Ruggles chat with Rak Siva and Steve Demchuck to talk about Nitric! That’s the Infrastructure from Code framework that makes it easy to use a cloud back-end in your code, using any of multiple providers, in multiple programming languages.

The group chatted about the role and form of good documentation, as well as whether a Contributor License Agreement is ever appropriate, and what a good CLA would actually look like. Don’t miss it!
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Robotic Platform Turns Shop Vac Into Roomba

May 8, 2024 by Bryan Cockfield 5 Comments

The robotic revolution is currently happening, although for the time being it seems as though most of the robots are still being generally helpful to humanity, whether that help is on an assembly line, help growing food, or help transporting us from place to place. They’ve even showed up in our homes, although it’s not quite the Jetsons-like future yet as they mostly help do cleaning tasks. There are companies that will sell things like robotic vacuum cleaners but [Clay Builds] wanted one of his own so he converted a shop vac instead.

The shop vac sits in a laser-cut plywood frame and rolls on an axle powered by windshield wiper motors. Power is provided from a questionable e-bike battery which drives the motors and control electronics. A beefy inverter is also added to power the four horsepower vacuum cleaner motor. The robot has the ability to sense collisions with walls and other obstacles, and changes its path in a semi-random way in order to provide the most amount of cleaning coverage for whatever floor it happens to be rolling on.

There are a few things keeping this build from replacing anyone’s Roomba, though. Due to the less-than-reputable battery, [Clay Builds] doesn’t want to leave the robot unattended and this turned out to be a good practice when he found another part of the build, a set of power resistors meant to limit current going to the vacuum, starting to smoke and melt some of the project enclosure. We can always think of more dangerous tools to attach a robotic platform to, though.

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Much Faster Cold Brew Through Cavitation

May 8, 2024 by Kristina Panos 11 Comments

Some coffee snobs might call this sacrilege. Cold brew is supposed to take a long time — that’s part of how it gets its characteristic smoothness. But a group of engineers from the University of New South Wales (UNSW Sydney) have figured out a way to cut the time down from several hours to a mere three minutes, using ultrasonic waves.

Typically, the cold brew coffee process takes between 12 and 24 hours. Enough time to steep the grounds and extract the flavors without the benefit of hot water. This is how it differs from iced coffee, which is brewed hot and poured over ice.

Interestingly, the UNSW Sydney engineers’ process uses a typical prosumer-grade espresso machine and involves blasting the portafilter with a transducer and a horn. This transforms the coffee basket into a sonoreactor. Sound waves at a frequency of 38.8 kHz are injected at multiple points through the walls, generating acoustic cavitation within. You can read all about it in Ultrasonics Sonochemistry.

That’s not even the most exciting part. The study found that this arrangement is capable of doubling both the extraction yield and caffeine concentration, compared with non-soundblasted samples. The team sent samples of the coffee off to be evaluated on aroma, texture, flavor, and aftertaste. Although the one-minute extraction samples received similar ratings to a 24-hour brew in terms of flavor and aftertaste, they lacked the intensity and dark chocolate aroma of the longer brew. But the three-minute extraction samples scored quite highly in all areas, suggesting that the average cold brew drinker wouldn’t be able to tell the difference.

Would you like to roast your own beans at home? You can use a popcorn popper, but you might get tired of semi-uneven roasts and upgrade to a DIY wobble disk roaster.

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