A fast-looking hand plays a reaction time game.

2024 Tiny Games Challenge: Improving Reaction Time

July 23, 2024 by 3 Comments

What lies at the heart of many games? In a sense, it’s your response time, which is a function of hand-eye coordination. Although the 2024 Business Card Challenge has come to a close, [gokux] tends to go small anyway, and has taken their miniature approach to the Tiny Games Challenge with this awesome little reaction time game.

It’s basically whack-a-mole, but instead of striking down fuzzy puppets, you get fast and furious on big buttons that light up. Press any button to start, and there is a 3-2-1 countdown to get you geared up for action. Once the screen says ‘GO’, you’re off to the races. Each of the four buttons will light up in random order, and your overall response time is taken as the average of these four.

While there are many microcontrollers that would work here, [gokux] chose the Seeed Studio Xiao ESP32-C3. If you want to make one of these for yourself, there are excellent build instructions waiting for you. Be sure to check it out in action after the break. Oh, and be sure to let [gokux] know if you can beat 220 ms.

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Illustrated Kristina with an IBM Model M keyboard floating between her hands.

Keebin’ With Kristina: The One With The Key Cap Map

July 23, 2024 by 5 Comments

So, [zyumbik]’s trademark seems to be sexing things up, and the Artsey layout did not escape their gaze. This is the Sexy Artsey. Let’s back up a bit.

A pink and purple 10-key keyboard with a rotary encoder, spikes, and a custom area with LEGO attached.
Image by [zyumbik] via reddit
Artsey is a keyboard layout for chording, and this keyboard is built for it. It’s a one-handed keyboard meant for pressing multiple keys at a time to produce each character. With some use, [zyumbik] discovered that the Taipo layout might be a better fit, so there are currently some elements of both.

If you’d like to make this adorable keyboard, everything is waiting for you to download, including files for various thingamabobs you can stick on the side there where the rainbow is now. There’s also a groovy flower version of the knob.

Controller-wise, you can use a Seeed Studio Xiao in either BLE or RP2040 format, or the Waveshare RP2040 Zero. The firmware is written in ZMK.

Remember the death metal macropad? (Who could forget that tentacled nightmare?) This is the same creator. Kind of hard to believe, innit? Well, except for the spikes. Apparently they’re for thumb discipline.

Via reddit

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Could Carbon Fiber Be The New Asbestos?

July 23, 2024 by 54 Comments

Could carbon fiber inflict the same kind of damage on the human body as asbestos? That’s the question which [Nathan] found himself struggling with after taking a look at carbon fiber-reinforced filament under a microscope, revealing a sight that brings to mind fibrous asbestos samples. Considering the absolutely horrifying impact that asbestos exposure can have, this is a totally pertinent question to ask. Fortunately, scientific studies have already been performed on this topic.

Example SEM and TEM images of the released particles following the rupture of CFRP cables in the tensile strength test. (Credit: Jing Wang et al, Journal of Nanobiotechnology, 2017)
Example SEM and TEM images of the released particles following the rupture of CFRP cables in the tensile strength test. (Credit: Jing Wang et al, Journal of Nanobiotechnology, 2017)

While [Nathan] demonstrated that the small lengths of carbon fiber (CF) contained in some FDM filaments love to get stuck in your skin and remain there even after washing one’s hands repeatedly, the aspect that makes asbestos such a hazard is that the mineral fibers are easily respirable due to their size. It is this property which allows asbestos fibers to nestle deep inside the lungs, where they pierce cell membranes and cause sustained inflammation, DNA damage and all too often lung cancer or worse.

Clearly, the 0.5 to 1 mm sized CF strands in FDM filaments aren’t easily inhaled, but as described by [Jing Wang] and colleagues in a 2017 Journal of Nanobiotechnology paper, CF can easily shatter into smaller, sharper fragments through mechanical operations (cutting, sanding, etc.) which can be respirable. It is thus damaged carbon fiber, whether from CF reinforced thermal polymers or other CF-containing materials, that poses a potential health risk. This is not unlike asbestos — which when stable in-situ poses no risk, but can create respirable clouds of fibers when disturbed. When handling CF-containing materials, especially for processing, wearing an effective respirator (at least N95/P2) that is rated for filtering out asbestos fibers would thus seem to be a wise precaution.

The treacherous aspect of asbestos and kin is that diseases like lung cancer and mesothelioma are not immediately noticeable after exposure, but can take decades to develop. In the case of mesothelioma, this can be between 15 and 30 years after exposure, so protecting yourself today with a good respirator is the only way you can be relatively certain that you will not be cursing your overconfident young self by that time.

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You Can Use LEDs As Sensors, Too

July 23, 2024 by 69 Comments

LEDs are a wonderful technology. You put in a little bit of power, and you get out a wonderful amount of light. They’re efficient, cheap, and plentiful. We use them for so much!

What you might not have known is that these humble components have a secret feature, one largely undocumented in the datasheets. You can use an LED as a light source, sure, but did you know you can use one as a sensor?

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Photoresistor-based Single Pixel Camera

July 23, 2024 by 18 Comments

[Hugh] has been going back through episodes of the Hackaday podcast, and Elliot mentioned in episode 67 that it can often be inspiring to go back through the archives of Hackaday to find ideas for new projects. Well, he did just that and came across a single-pixel camera made using an infrared photodiode. He decided to try and hack together his own single-pixel camera, but this time on the cheap and using an ever simpler component – a photoresistor!

His description of the project tickled me – “I’ve used an ESP32, MicroPython, two servos, a peanut butter jar lid, a toilet paper roll, a paper towel roll, magnets and scrap wood for this version.” That’s certainly a much simpler bill of materials than the original (which was written up by Hackaday way back in 2015), which used a nice metal frame to hold everything together. However, there’s absolutely nothing wrong with improvising with things you happen to have to hand.

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Brain Implant Uses Graphene Instead Of Metal Probes

July 23, 2024 by 7 Comments

Implantable electrodes for the (human) brain have been around for a many decades in the form of Utah arrays and kin, but these tend to be made out of metal, which can cause issues when stimulating the surrounding neurons with an induced current. This is due to faradaic processes between the metal probe and an electrolyte (i.e. the cerebrospinal fluid). Over time this can result in insulating deposits forming on the probe’s surface, reducing their effectiveness.

Graphene-based, high-resolution cortical brain interface (Credit: Inbrain Neuroelectronics)
Graphene-based, high-resolution cortical brain interface (Credit: Inbrain Neuroelectronics)

Now a company called InBrain claims to have cracked making electrodes out of graphene, following a series of tests on non-human test subjects. Unlike metal probes, these carbon-based probes should be significantly more biocompatible even when used for brain stimulation as with the target goal of treating the symptoms associated with Alzheimer’s.

During the upcoming first phase human subjects would have these implants installed where they would monitor brain activity in Alzheimer’s patients, to gauge how well their medication is helping with the symptoms like tremors. Later these devices would provide deep-brain stimulation, purportedly more efficiently than similar therapies in use today. The FDA was impressed enough at least to give it the ‘breakthrough device’ designation, though it is hard to wade through the marketing hype to get a clear picture of the technology in question.

In their most recently published paper (preprint) in Nature Nanotechnology, [Calia] and colleagues describe flexible graphene depth neural probes (gDNP) which appear to be what is being talked about. These gDNP are used in the experiment to simultaneously record infraslow (<0.1 Hz) and higher frequencies, a feat which metal microelectrodes are claimed to struggle with.

Although few details are available right now, we welcome any brain microelectrode array improvements, as they are incredibly important for many types of medical therapies and research.

Exploring Cheap Tantalum Caps Of Mysterious Provenance

July 22, 2024 by 27 Comments

We’ve all heard about the perils of counterfeit chips, and more than a few of us have probably been bitten by those scruple-free types who run random chips through a laser marker and foist them off as something they’re not. Honestly, we’ve never understood the business model here — it seems like the counterfeiters spend almost as much time and effort faking chips as they would just getting the real ones. But we digress.

Unfortunately, integrated circuits aren’t the only parts that can be profitably faked, as [Amateur Hardware Repair] shows us with this look at questionable tantalum capacitors. In the market for some tantalums for a repair project, the offerings at AliExpress proved too tempting to resist, despite being advertised alongside 1,000 gram gold bars for $121 each. Wisely, he also ordered samples from more reputable dealers like LCSC, DigiKey, and Mouser, although not at the same improbably low unit price.

It was pretty much clear where this would be going just from the shipping. While the parts houses all shipped their tantalums in Mylar bags with humidity indicators, with all but LCSC including a desiccant pack, the AliExpress package came carefully enrobed in — plastic cling wrap? The Ali tantalums were also physically different from the other parts: they were considerably smaller, the leads seemed a little chowdered up, and the package markings were quite messy and somewhat illegible. But the proof is in the testing, and while all the more expensive parts tested fine in terms of capacitance and equivalent series resistance, the caps of unknown provenance had ESRs in the 30 milliohm range, three to five times what the reputable caps measured.

None of this is to say that there aren’t some screaming deals on marketplaces like AliExpress, Amazon, and eBay, of course. It’s not even necessarily proof that these parts were in fact counterfeit, it could be that they were just surplus parts that hadn’t been stored under controlled conditions. But you get what you pay for, and as noted in the comments below the video, a lot of what you’re paying for at the parts houses is lot tracebility.

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