Hackaday Links Column Banner

Hackaday Links: March 22, 2020

Within the span of just two months, our world of unimaginable plenty and ready access to goods manufactured across the globe has been transformed into one where the bare essentials of life are hard to find at any price. The people on the frontline of the battle against COVID-19 are suffering supply chain pinches too, often at great risk to their health. Lack of proper personal protective equipment (PPE), especially face masks, is an acute problem, and the shortage will only exacerbate the problem as healthcare workers go down for the count. Factories are gearing up to make more masks, but in the meantime, the maker and hacker community can pitch in. FreeSewing, an open-source repository of sewing patterns, has a pattern for a simple face mask called the Fu that can be made quickly by an experienced threadworker. Efficacy of the masks made with that pattern will vary based on the materials used, obviously; a slightly less ad hoc effort is the 100 Million Mask Challenge, where volunteers are given a pattern and enough lab-tested materials to make 100 face masks. If you know how to sew, getting involved might make a difference.

As people around the world wrap their heads around the new normal of social distancing and the loss of human contact, there’s been an understandable spike in interest in amateur radio. QRZ.com reports that the FCC has recorded an uptick in the number of amateur radio licenses issued since the COVID-19 outbreak, and license test prep site HamRadioPrep.com has been swamped by new users seeking to prepare for taking the test. As we’ve discussed, the barrier for entry to ham radio is normally very low, both in terms of getting your license and getting the minimal equipment needed to get on the air. One hurdle aspiring hams might face is the cancellation of so-called VE testing, where Volunteer Examiners administer the written tests needed for each license class. Finding a face-to-face VE testing session now might be hard, but the VEs are likely to find a way to adapt. After all, hams were social distancing before social distancing was cool.

The list of public events that have been postponed or outright canceled by this pandemic is long indeed, with pretty much everything expected to draw more than a handful of people put into limbo. The hacking world is not immune, of course, with many high-profile events scuttled. But we hackers are a resourceful bunch, and the 10th annual Open Source Hardware Summit managed to go off on schedule as a virtual meeting last week. You can watch the nearly eight-hour livestream while you’re self-isolating. We’re confident that other conferences will go virtual in the near-term too rather than cancel outright.

And finally, if you’re sick of pandemic news and just want some escapist engineering eye candy, you could do worse than checking out what it takes to make a DSLR camera waterproof. We’ve honestly always numbered cameras as among the very least waterproof devices, but it turns out that photojournalists and filmmakers are pretty rough on their gear and expect it to keep working even so. The story here focuses (sorry) on Olympus cameras and lenses, which you’ll note that Takasu-san only ever refers to as “splash-proof”, and the complex system of O-rings and seals needed to keep water away from their innards. For our money, the best part was learning that lenses that have to change their internal volume, like zoom lenses, need to be vented so that air can move in and out. The engineering needed to keep water out of a vented system like that is pretty impressive.

Macro Photography With Industrial Lenses

Line scan cameras are advanced devices used for process inspection tasks in industrial applications. Used to monitor the quality of silicon wafers and other high-accuracy tasks, they’re often outfitted with top-quality optics that are highly specialised. [Peter] was able to get his hands on a lens for a line-scan camera, and decided to put it to work on some macro photography instead.

Macro image taken with the hacked lens.

Judging by the specs found online, this is a fairly serious piece of kit. It easily competes with top-shelf commercial optics, which is what piqued [Peter]’s interest in the part. Being such a specialised piece of hardware, you can’t just cruise over to eBay for an off-the-shelf adapter. Instead, a long chain of parts were used to affix this lens to a Sony AIII DSLR, converting from threaded fittings to a Nikon mount and then finally to Sony NEX mount.

Further work involved fitting an aperture into the chain to get the lens as close as possible to telecentric. This improves the lens’s performance for certain tasks, and makes focus stacking macro shots more readily achievable – something we’ve seen [Peter] tinker with before.

You never know what you might find when sorting through surplus industrial gear, could could score some high-performance hardware if you know where to look. It’s always great to see a cheap find become a useful instrument in the hacker toolbox!

Image Sensor From Discrete Parts Delivers Glorious 1-Kilopixel Images

Chances are pretty good that you have at least one digital image sensor somewhere close to you at this moment, likely within arm’s reach. The ubiquity of digital cameras is due to how cheap these sensors have become, and how easy they are to integrate into all sorts of devices. So why in the world would someone want to build an image sensor from discrete parts that’s 12,000 times worse than the average smartphone camera? Because, why not?

[Sean Hodgins] originally started this project as a digital pinhole camera, which is why it was called “digiObscura.” The idea was to build a 32×32 array of photosensors and focus light on it using only a pinhole, but that proved optically difficult as the small aperture greatly reduced the amount of light striking the array. The sensor, though, is where the interesting stuff is. [Sean] soldered 1,024 ALS-PT19 surface-mount phototransistors to the custom PCB along with two 32-bit analog multiplexers. The multiplexers are driven by a microcontroller to select each pixel in turn, one row and one column at a time. It takes a full five seconds to scan the array, so taking a picture hearkens back to the long exposures common in the early days of photography. And sure, it’s only a 1-kilopixel image, but it works.

[Sean] has had this project cooking for a while – in fact, the multiplexers he used for the camera came up as a separate project back in 2018. We’re glad to see that he got the rest built, even with the recycled lens he used. One wonders how a 3D-printed lens would work in front of that sensor.

Continue reading “Image Sensor From Discrete Parts Delivers Glorious 1-Kilopixel Images”

Acoustic Lenses Show Sound Can Be Focused Like Light

Acoustic lenses are remarkable devices that just got cooler. A recent presentation at SIGGRAPH 2019 showed that with the help of 3D printing, it is possible to build the acoustic equivalent of optical devices. That is to say, configurations that redirect or focus sound waves. One fascinating demonstration worked like an acoustic prism, able to send different notes from a simple melody in different directions. Another was a device that dynamically varied the distance between two lenses in order to focus sound onto a moving target. In both cases, the sounds originate from an ordinary speaker and are shaped by passing through the acoustic lens or lenses, which are entirely passive devices.

Researchers from the University of Sussex used 3D printing for a modular approach to acoustic lens design. 16 different pre-printed “bricks” (shown here) can be assembled in various combinations to get different results. There are limitations, however. The demonstration lenses only work in a narrow bandwidth, meaning that the sound they work with is limited to about an octave at best. That’s enough for a simple melody, but not nearly enough to cover a human’s full audible range. Download the PDF for a quick read about the details, it’s only two pages but loaded with enough to whet your appetite to know more.

Directional sound can be done in other ways as well, such as using an array of ultrasonic emitters to create a coherent beam of sound. Ultrasonic emitters can even levitate lightweight objects. Ain’t sound neat?

3D-Printed Extension For Extreme Macro Photography Includes Lens Electronic Control

Macro photography — the art of taking pictures of tiny things — can be an expensive pastime. Good lenses aren’t cheap, and greater magnification inflates the price even further. One way to release a bit more performance from your optics comes in the form of an extension tube, which mounts your lens further from the camera to zoom in a little on the image. Back in the day with a film SLR you could make a rough and ready tube with cardboard and tape, but in the age of the digital camera the lens has become as much a computer peripheral as an optical device. [Nicholas Sherlock] has solved this problem by creating a 3D-printed extension tube for his Canon that preserves connections between camera and lens.

More details of this 300mm monster’s construction go so far beyond a plastic tub formed of two threaded sections with adapter plates at the ends. He’s using off-the-shelf metal rings to fit camera and lens just right, but making the electronic contacts is where it gets interesting. On end uses pogo pins, the other provides a contact block made of nail heads. In both cases the 3D-printed parts are designed to provide mounting points for the pins and nails. The assembly technique is worth a look both because of the design and as an example of how to document all the juicy details we’re constantly looking for in a great hack.

The results speak for themselves, in that the photography provides an impressive level of close-up detail. If you would like to build your own tube, it is available on Thingiverse.

Macro extensions seem far between here, but we’ve brought you a few lens repairs in our time.

[via /r/photography]

Expensive Sony Lens Repair Reveals Shims & Shifts

The photographic hire company Lensrentals had a $2k Sony FE 135mm f1.8 GM camera lens returned with a problem: it was having issues focusing. So, they decided to do the obvious thing and take it apart. It’s a fascinating insight into some of the engineering that goes into a high-end camera lens.

That is perhaps a rather scary thing to do, because this is a very new lens that doesn’t even have a service manual yet. That’s akin to rechipping a Ferrari when you’ve never even opened the hood before.

One of the interesting things inside is the presence of a number of shims that adjust the placement between the groups of lens elements. It seems that however good their manufacturing tolerances are, sometimes you just have to put a shim or two in there to align things.

Continue reading “Expensive Sony Lens Repair Reveals Shims & Shifts”

Hold 3500 Volts Up To Your Eye

Old military equipment can sometimes be found in places like flea markets and eBay for pennies, often because people don’t always know what they have. While [tsbrownie] knew exactly what he was getting when he ordered this mystery device, we’re not sure we could say the same thing if we stumbled upon it ourselves. What looks like a vacuum tube of some sort turns out to be an infrared sensor from an old submarine periscope that was repurposed as a night vision device. (Video, embedded below.)

Of course, getting a tube like this to work requires high voltage. This one specifically needs 3500V in order to work properly, but this was taken care of with a small circuit housed in a PVC-like enclosure. The enclosure houses the tube in the center, with an eye piece at one end and a camera lens at the other, attached presumably by a 3D-printed mount. The electronics are housed in the “grip” and the whole thing looks like a small sightglass with a handle. Once powered up, the device is able to show a classic green night vision scene.

Old analog equipment like this is pretty rare, as are people with the expertise to find these devices and get them working again in some capacity. This is a great video for anyone with an interest in tubes, old military gear, or even if you already built a more modern night vision system a while back.

Thanks to [Zzp100] for the tip!

Continue reading “Hold 3500 Volts Up To Your Eye”