Old Film Camera Modified For Different Chemistry

While most photographers have moved on to digital cameras with their numerous benefits, there are a few artists out there still taking pictures with film. While film is among the more well-known analog photographic methods available, there are chemically simpler ways of taking pictures available for those willing to experiment a little bit. Cyanotype photography is one of these methods, and as [JGJMatt] shows, it only takes a few commonly available chemicals, some paper, and a slightly modified box camera to get started.

Cyanotype photography works by adding UV-reactive chemicals to paper and exposing the paper similarly to how film would be exposed. The photographs come out blue wherever the paper wasn’t exposed and white where it was. Before mixing up chemicals and taking photos, though, [JGJMatt] needed to restore an old Kodak Brownie camera, designed to use a now expensive type of film. Once the camera is cleaned up, only a few modifications are needed to adapt it to the cyanotype method, one of which involves placing a magnet on the shutter to keep it open for the longer exposure times needed for this type of photography. There is some development to do on these pictures, but it’s relatively simple to do in comparison to more traditional chemical film development.

For anyone looking for a different way of taking photographs, or even those looking for a method of taking analog pictures without the hassle of developing film or creating a darkroom, cyanotype offers a much easier entry point and plenty of artists creating images with this method don’t use a camera at all. There are plenty of other photographic chemistries to explore as well; one of our favorites uses platinum to create striking black-and-white photos.

Reliable 3D Printing With Ceramic Slurry

3D printing is at its most accessible (and most affordable) when printing in various plastics or resin. Printers of this sort are available for less than the cost of plenty of common power tools. Printing in materials other than plastic, though, can be a bit more involved. There are printers now for various metals and even concrete, but these can be orders of magnitude more expensive than their plastic cousins. And then there are materials which haven’t really materialized into a viable 3D printing system. Ceramic is one of those, and while there are some printers that can print in ceramic, this latest printer makes some excellent strides in the technology.

Existing technology for printing in ceramic uses a type of ceramic slurry as the print medium, and then curing it with ultraviolet light to solidify the material. The problem with ultraviolet light is that it doesn’t penetrate particularly far into the slurry, only meaningfully curing the outside portions. This can lead to problems, especially around support structures, with the viability of the prints. The key improvement that the team at Jiangnan University made was using near-infrared light to cure the prints instead, allowing the energy to penetrate much further into the material for better curing. This also greatly reduces or eliminates the need for supports in the print.

The paper about the method is available in full at Nature, documenting all of the details surrounding this new system. It may be a while until this method is available to a wider audience, though. If you can get by with a print material that’s a little less exotic, it’s not too hard to get a metal 3D printer, as long as you are familiar with a bit of electrochemistry.

Sunshine In A Bag

Ultraviolet (UV) curing lamps are crucial if you have a resin 3D printer or work with UV adhesives. Some folks line an old Amazon shipping box with foil and drop a spotlight somewhere inside. Other folks toss their work under the all-natural light source, Sol. Both options have portability and reliability problems, but [AudreyObscura] has it covered with a reflective mat lined with UV strip lights. This HackadayPrize2020 finalist exemplifies the ideal that good ideas are often simple, and this has a remarkably short bill of materials.

Foil bubble insulation is the medium because it provides structure and reflectivity, but it doesn’t cooperate with the LED strip’s adhesive. [AudreyObscura] demonstrates that masking tape as an interfacing layer makes everyone play nicely. A fine example of an experienced maker, their design covers bundling wires and insulating connections to keep everything tidy and isolated. With different arrangements, this can form a tunnel lit from above, a chimney lit from the walls, or you can drape it over some scaffolding.

If you need something a little less portable for your own shop you might consider a mirror-filled chamber. One nice touch to add is a turntable to help make sure the entire part is cured without any missing areas.

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Buyer Beware: This LED Bulb Sold As Germicidal Doesn’t Emit UV-C

Germicidal lamps are designed to destroy viruses and bacteria using ultraviolet light. But not just any UV light will work, and I came across an example of a lamp that was advertised as germicidal but a few things just weren’t right about it.

This is an actual UV-C LED made by CEL (PDF) that emits 275nm. Note the clear glass that covers the LED.

I ordered the UV-C germicidal LED lamp on Amazon, and received it a few days ago. It felt the suspicion from the first moment: playing around with a lot of different UV LEDs, I’ve learnt how the parasitic visible light from different UV ranges should look like to human eye. Also, proper UV-C LED lenses like the one shown here are made of quartz glass. Compare that to the image at the top of the article of the bulb I received that has a soft plastic lens, which is possibly opaque and degradable in the far UV range. The most important clue that something was wrong was the price. It’s hard to imagine that a UV-C LED lamp with the 253.7nm wavelength, made of more than 200 LEDs and in such a robust metal case, can cost only $62.99.

Although there was the risk of being unjust, I decided to return the product. In my message I bluffed that I measured the spectra of the lamp with a spectral emission meter, and that its output was not in the UV-C range. The next day I received confirmation that the bluff paid off: the seller replied that they advertised the product according to information from the supplier, and that the incorrect information was caused by their lack of understanding of product information. They also attached the official datasheet with the measured wavelength: it was not 253.7 nm, as advertised, but with the peak at 394.3 nm, and the dominant wavelength at 413.9 nm. It was not in the far UV-C, but in the near UV-A range and not at all useful for destroying germs! The seller promised that the product would be removed from their store, and kept the promise.

If you are thinking about buying a UV-C LED lamp, maybe you should get the good old CFL germicidal lamp. I don’t think that viruses care too much about the new technology.

Fail Of The Week: EPROMs, Rats’ Nests, Tanning Lamps, And Cardboard On Fire

It all started when I bought a late-1990s synthesizer that needed a firmware upgrade. One could simply pull the ROM chip, ship it off to Yamaha for a free replacement, and swap in the new one — in 2003. Lacking a time machine, a sensible option is to buy a pre-programmed aftermarket EPROM on eBay for $10, and if you just want a single pre-flashed EPROM that’s probably the right way to go. But I wanted an adventure.

Spoiler alert: I did manage to flash a few EPROMs and the RM1X is happily running OS 1.13 and pumping out the jams. That’s not the adventure. The adventure is trying to erase UV-erasable EPROMS.

And that’s how I ended up with a small cardboard fire and a scorched tanning lamp, and why I bought a $5 LED, and why I left EPROMs out in the sun for four days. And why, in the end, I gave up and ordered a $15 EPROM eraser from China. Along the way, I learned a ton about old-school UV-erasable EPROMs, and now I have a stack of obsolete silicon that’s looking for a new project like a hammer looks for a nail — just as soon as that UV eraser arrives in the mail.

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Incredible 3D Printed Overwatch Airsoft Pistol

If you ever needed evidence that gamers are some of the most dedicated individuals in all of fandom, then look no further than this fantastic 3D printed recreation of the “Pulse Pistol” as featured in the immensely popular “Overwatch”. Built by the guys at [Danger Doc], this replica doesn’t just look the part, it’s also a fully functional Airsoft gun. In the detailed build video after the break, the year-long design and construction of the gun is broken down for your viewing pleasure.

Because the end goal was to make something that looked as though it came from the game itself, a lot of time was put into making sure that the externals were faithful to the digital version while still able to contain all the hardware they needed to cram in there. This is a fully auto gun, so it needed a battery and motors, as well as a way to feed the firing mechanism Airsoft BBs that didn’t require an anachronistic magazine sticking out.

They combined a off-the-shelf firing mechanism and high-capacity magazine but it took plenty of custom designed parts to get everything mated up. The magazine has a clockwork mechanism to advance the BBs which required the user to manually crank up, but this was replaced with an electric motor to make things a little more futuristic. In addition to all the LEDs on the body of the gun, there’s also an internal array of ultraviolet SMD LEDs to charge the glow-in-the-dark “tracer” BBs as they move through the magazine. In low light, this gives the shots from the gun something of a laser effect.

We’ve seen 3D printed guns from games before, but rarely with this attention to detail and engineering. Honestly, this even gives some¬†real 3D printed guns a run for their money.

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Improvising An EPROM Eraser

Back in the old days, when we were still twiddling bits with magnetized needles, changing the data on an EPROM wasn’t as simple as shoving it in a programmer. These memory¬†chips were erased with UV light shining through a quartz window onto a silicon die. At the time, there were neat little blacklights in a box sold to erase these chips. There’s little need for these chip erasers now, so how do you erase and program a chip these days? Build your own chip eraser using components that would have blown minds back in the 70s.

[Charles] got his hands on an old 2764 EPROM for a project, but this chip had a problem — there was still data on it. Fortunately, old electronics are highly resistant to abuse, so he pulled out the obvious equipment to erase this chip, a 300 watt tanning lamp. This almost burnt down the house, and after a second round of erasing of six hours under the lamp, there were still unerased bits.

Our ability to generate UV light has improved dramatically over the last fifty years, and [Charles] remembered he had an assortment of LEDs, including a few tiny 5mW UV LEDs. Can five milliwatts do what three hundred watts couldn’t? Yes; the LED had the right frequency to flip a bit, and erasing an EPROM is a function of intensity and time. All you really need to do is shine a LED onto a chip for a few hours.

With this vintage chip erased, [Charles] slapped together an EPROM programmer — with a programming voltage of 21V — out of an ATMega and a bench power supply. It eventually worked, allowing [Charles]’ project, a vintage liquid crystal display, to have the right data using vintage-correct parts.