Finding a Lost Tooth With Science!

Sometimes the hack is a masterwork of circuit design, crafting, 3D printing and programming. Other times, the hack is knowing which tool is right for the job, even when the job isn’t your regular, run-of-the-mill, job. [John]’s son lost his tooth on their gravel driveway, so [John] set out to find it.

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White socks fluoresce under UV

When [John] set out to help his son and find the tooth, he needed a plan of attack – there was a large area to cover and, when [John] looked over the expanse of gravel the terms “needle” and “haystack” came to mind. Just scanning the ground wasn’t going to work, he needed a way to differentiate the tooth from the background. Luckily, he had a UV flashlight handy and, after testing it on his own teeth, realized that his son’s tooth would fluoresce under UV light and the gravel wouldn’t.

Off [John] went at night to find the tooth with his flashlight. He soon realized that many things fluoresce under UV light – bits of plastic, quartz crystal in the rocks, his socks. [John] eventually found the tooth, and his son is happier now. No soldering was involved, no development on breadboards, no high-voltage, but this is one of those hacks that is more about problem solving than throwing microcontrollers at a situation. In the end, though, everyone’s happy, and that’s what counts.

Extracting Sounds With Acid And UV

Toaplan was a Japanese video game developer in the 80s and early 90s, most famous for Zero Wing, the source of the ancient ‘All Your Base’ meme. Memeology has come a long way since the Something Awful forums and a pre-Google Internet, but MAME hasn’t. Despite the completionist nature of MAME aficionados, there are still four Toaplan games with no sound in the current version of MAME.

The sound files for these games is something of a holy grail for connoisseurs of old arcade games, and efforts to extract these sounds have been fruitless for three decades. Now, finally, these sounds have been released with the help of sulfuric acid and microscopes.

The sounds for Fire SharkVimanaTeki Paki, and Ghox were stored on their respective arcade boards inside the ROM for a microcontroller, separate from the actual game ROM. Since the fuse bits of this microcontroller were set, the only way to extract the data was decapsulation. This messy and precise work was done by CAPS0ff, who melted away the epoxy coating of the chip, revealing the microcontroller core.

Even without a microscope, the quarry of this hunt was plainly visible, but there was still no way to read out the data. The built-in read prevention bit was set, and the only way to clear that was to un-set a fuse. This was done by masking everything on the chip except the suspected fuse, putting it under UV, and checking if the fuse switched itself to an unburnt state.

The data extraction worked, and now the MAME project has the sound data for games that would have otherwise been forgotten to time. A great success, even if the games are generic top-down shooters.

Robots With 3D Printed Shock Absorbing Skin

MIT’s Computer Science and Artificial Intelligence Laboratory, CSAIL, put out a paper recently about an interesting advance in 3D printing. Naturally, being the computer science and AI lab the paper had a robotic bend to it. In summary, they can 3D print a robot with a rubber skin of arbitrarily varying stiffness. The end goal? Shock absorbing skin!

They modified an Objet printer to print simultaneously using three materials. One is a UV curing solid. One is a UV curing rubber, and the other is an unreactive liquid. By carefully depositing these in a pattern they can print a material with any property they like. In doing so they have been able to print mono body robots that, simply put, crash into the ground better.  There are other uses of course, from joints to sensor housings. There’s more in the paper.

We’re not sure how this compares to the Objet’s existing ability to mix flexible resins together to produce different Shore ratings. Likely this offers more seamless transitions and a wider range of material properties. From the paper it also appears to dampen better than the alternatives. Either way, it’s an interesting advance and approach. We wonder if it’s possible to reproduce on a larger scale with FDM.

Seeing the Truly Invisible with DIY Shortwave UV Imaging

We’ve all seen how to peel IR filters off digital cameras so they can see a little better in the dark, but there’s so much more to this next project than that. How about being able to see things normally completely outside the visual spectrum, like hydrogen combustion or electrical discharges?

UV Electrical Discharge

[David Prutchi] has just shared his incredible work on making his own shortwave ultraviolet viewers for imaging entirely outside of the normal visible spectrum – in other words, seeing the truly invisible. The project has not only fascinating application examples, but provides detailed information about how to build two different imagers – complete with exact part numbers and sources.

UV-Viewer-SmallIf you’re thinking UV is a broad brush, you’re right. [David Prutchi] says he is most interested in Solar Blind UV (SBUV):

Solar radiation in the 240 nm to 280 nm range is completely absorbed by the ozone in the atmosphere and cannot reach Earth’s surface…

Without interference from background light, even very weak levels of UV are detectable. This allows ultraviolet-emitting phenomena (e.g. electrical discharges, hydrogen combustion, etc.) to be detectable in full daylight.

There is more to the process than simply slapping a UV filter onto a camera, but happily he addresses all the details and the information is also available as a PDF whitepaper. [David Prutchi] has been working with imaging for a long time, and with his sharing of detailed build plans and exact part numbers maybe others will get in on the fun. He’s also previously shared full build plans for a Raspberry Pi based multispectral imager, [David’s] DOLPHi Polarization Camera was a finalist in the 2015 Hackaday Prize, and he spoke at the Hackaday SuperConference about the usefulness of advanced imaging techniques for things like tissue analysis in medical procedures, and landmine detection for the purposes of cleaning up hazardous areas.

UV Photographic Printer Lets You Use Strange Chemistries

There is a family of old photographic chemistries based on iron compounds which, like the blueprint, are exposed using UV light. Ironically, the digital camera revolution which has made everything else in our photographic lives much easier, has made it harder to experiment around with these alternative methods. [David Brown] is making a UV photographic printer to change that.

[David]’s application has a lot in common with PCB printers that use a UV-sensitive resist, only [David] needs greyscale, and it might also be nice if it could work with wet paper. This makes it a more challenging project than you might think, but we like the cut of [David]’s jib.

Like some of the other UV exposer projects, [David]’s uses a rotating mirror to scan across the to-be photograph’s surface. Unlike the other ones that we’ve seen, the exposer hangs from two linear rails. Other printers move the paper underneath a stationary scanning head, which seems a mechanically simpler arrangement. We’re excited to see how this goes.

There’s a lot of interest in UV PCB printers right now. We’ve seen one made from junked CD-ROM drives on one end of the spectrum to one made by retrofitting a delta robot on the other. And don’t disregard the work done by folks interested in UV-curing 3D printers, either.

EPROM Timer

[glitch] had a cheap EPROM eraser with very few features. Actually, that might be giving it too much credit: it’s barely more than a UV light that turns on when it’s plugged in and turns off when it’s plugged out unplugged. Of course it would be nice to implement some safety features, so he decided he’d hook it up to a software-controlled power outlet.

Of course, controlling a relay that’s wired to mains is old hat around here, and in fact, we’ve covered [glitch]’s optoisolated mains switch already. He’s gone a little beyond the normal mains relay project with this one, though. Rather than use a microcontroller to run the relay, [glitch] wrote a simple Ruby script on his computer to turn the EPROM eraser on for the precise amount of time that is required to erase the memory.The Ruby script drives the relay control directly over a USB to serial adapter’s RTS handshake pin.

[glitch]’s hack reminds us that if you just need a quick couple bits of slow output, a USB-serial converter might be just the ticket. You could imagine driving everything from standard lamps to your 3D printer’s bed heater (provided you use similar hardware), but it’s especially helpful for [glitch] who claims to forget to turn off the eraser when it’s done its job, which leaves a potentially dangerous UV source just lying about. It’s always a good idea to add safety features to a dangerous piece of equipment!

The Ultimate Tool For Homebrew PCB Manufacturing

While OSHPark, Seeed Studio, and DirtyPCB have taken most of the fun and urgency out of making your own circuit boards at home, there are still a few niche cases and weird people who like to go it alone. For them, [Jarzębski] has created the ultimate homebrew PCB manufacturing solution (.pl, here’s the Google translatrix).

[Jarzębski] is using UV-sensitive photomasks for his PCBs, but he’s not doing something simple like a blacklight to develop his boards. He’s using a 30 Watt UV LED for exposing his boards. This, of course, generates a lot of heat and to mitigate that he’s added a Peltier cooler, temperature sensor, and a fan to cool off this retina-burning LED. 30 Watts will get the job done, considering [Jarzębski] was using a quartet of 4.5W LEDs before this build.

Developing a PCB is only one part of the equation; you need to etch it, too. For this, [Jarzębski] is using a small 1.6 Liter aquarium and four aquarium heaters for dunking 120mm x 120mm PCBs in the tank. There’s no mention of what chemistry [Jarzębski] is using – ferric chloride, cupric chloride, or otherwise – but the heaters and aerator should make etching go very smoothly.

There’s a video (English) going over the rest of the project below.

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