Raspberry Pi Crammed Into Old Film Camera

If you wanted an expensive film camera when you were a kid, you are in luck. Used film SLRs are super cheap now that everyone wants digital cameras. Of course, in reality, you want a digital camera, too. So do what [befinitiv] did. Make a film cartridge out of a Raspberry Pi that can convert your camera to digital. (Video, embedded below.)

In theory, this sounds like a genius idea. The practical aspect isn’t perfect, though. For one thing, the small image sensor used means that the camera is zoomed in quite a bit. Also, the shutter button isn’t integrated, so the shutter is open all the time. You may think that doesn’t matter, but don’t forget that the way an SLR works means if the shutter is open, there’s no viewfinder.

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One Of The Largest Large Format Cameras You Will Ever Have Seen

When fate lands a very high quality lens in front of you, what do you do with it? If you are [Tim Hamilton], the solution is obvious. Use it in a huge large-format camera.

The lens came from a newspaper magnifier made redundant by digitalisation and used as a paperweight. It’s an extremely high quality piece of optical equipment so seeing it wasted in this way was a source of distress. So after characterising it an enormous scaled-up box and bellows was constructed, and set upon a suitably substantial wheeled tripod.

Instead of a huge piece of film or some unobtainable giant electronic sensor, the image is projected onto a large screen at the rear of the camera. A modern digital camera is mounted inside the box just beneath the lens and photographs the screen, resulting in the feel of the largest of large format cameras with the convenience of a digital format. The resulting images have a special quality to them that recalls pictures from the past, and definitely makes the camera a special if slightly inconvenient device.

This may be one of the larger cameras we’ve featured, but it’s not the first that uses a similar technique.

Image Sensors Demystified By [IMSAI Guy]

The February 1975 issue of Popular Electronics had what was — at the time — an amazing project. The Cyclops, a digital camera with a 32 by 32 pixel resolution with 4 bits per pixel. It was hard to imagine then that we would now all carry around high-resolution color cameras that were also phones, network terminals, and so many other things. But how much do you know about how those cameras really work? If you want to know more, check out [IMSAI Guy’s] recent video on how image sensors work.

The video doesn’t cover any practical projects or circuits, but it has a good explanation of what goes on in modern digital cameras. If you don’t know what digital cameras have in common with an octopus, you might want to watch.

If you want to see what the state of the art in 1975 was, have a look at this post. The image sensor in that camera didn’t have much in common with the ones we use today, but you have to admit it is clever. Of course, 1975 was also the year Kodak developed a digital camera and failed to understand what to do with it. Like the Cyclops, it had little in common with our modern smartphone cameras, but you have to start somewhere.

Hacking A Digital Microscope Camera For Fun And Automated PCB Inspection

A desire for automated PCB inspection has led [charliex] down some deep rabbit holes. He’s written his own inspection software, he’s mounted his PCB vise on a stepper-controlled table, and now he’s hacked his digital microscope camera to allow remote and automated control.

Eakins cameras have become a relatively popular, relatively inexpensive choice for electronics hobbyists to inspect their small-scale work. The cameras have a USB port for a mouse and overlay a GUI on the HDMI output for controlling the camera’s various settings and capturing images to the SD card. Using the mouse-based GUI can feel clunky, though, so users have already endeavored to streamline the process to fit better in their workflow. [charliex] decided to take streamlining a few steps further.

One issue in microscope photography is that microscopes have an extremely tight focus plane. So, even at the minuscule scales of an SMD circuit board, the components are simply too tall. Only a sub-millimeter-thick layer can be in focus at a time. If you take just a single image, much of what you want to see will be lost in the blurry distance. Focus stacking solves this problem by taking multiple pictures with the focus set at different depths then combining their focused bits into a single sharp image.

This takes care of the focus issue, but even the most streamlined and intuitive manual controls become tedious given the multitude of pictures required. So [charliex] searched for a way to remotely control his camera, automating focus stacking and possibly even full PCB scans.

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Tracking Drone Flight Path Via Video, Using Cameras We Can Get

Calculating three-dimensional position from two-dimensional projections are literal textbook examples in geometry, but those examples are the “assume a spherical cow” type of simplifications. Applicable only in an ideal world where the projections are made with mathematically perfect cameras at precisely known locations with infinite resolution. Making things work in the real world is a lot harder. But not only have [Jingtong Li, Jesse Murray et al.] worked through the math of tracking a drone’s 3D flight from 2D video, they’ve released their MultiViewUnsynch software on GitHub so we can all play with it.

Instead of laboratory grade optical instruments, the cameras used in these experiments are available at our local consumer electronics store. A table in their paper Reconstruction of 3D Flight Trajectories from Ad-Hoc Camera Networks (arXiv:2003.04784) listed several Huawei cell phone cameras, a few Sony digital cameras, and a GoPro 3. Video cameras don’t need to be placed in any particular arrangement, because positions are calculated from their video footage. Correlating overlapping footage from dissimilar cameras is a challenge all in itself, since these cameras record at varying framerates ranging from 25 to 59.94 frames per second. Furthermore, these cameras all have rolling shutters, which adds an extra variable as scanlines in a frame are taken at slightly different times. This is not an easy problem.

There is a lot of interest in tracking drone flights, especially those flying where they are not welcome. And not everyone have the budget for high-end equipment or the permission to emit electromagnetic signals. MultiViewUnsynch is not quite there yet, as it tracks a single target and video files were processed afterwards. The eventual goal is to evolve this capability to track multiple targets on live video, and hopefully help reduce frustrating public embarrassments.

[IROS 2020 Presentation video (duration 14:45) requires free registration, available until at least Nov. 25th 2020.]

Why Are Digital Cameras Still Boring?

In the matter of technological advancement, we are as a species, mostly insatiable. The latest toy, the fastest silicon, the largest storage, the list goes on. Take digital cameras as an example, what was your first one? Mine was a Casio QV200 in about 1997, I still have it somewhere though I can’t immediately lay my hands on it, and it could hold a what was for its time a whopping 64 VGA-resolution pictures in its 4Mb of onboard memory.

The QV200 showing off its VGA capabilities. It's March 1998, and this is a brand-new PlayStation that I'm about to install a mod chip inside.
The QV200 showing off its VGA photography capabilities. It’s March 1998, and this is a brand-new PlayStation that I’m about to install a mod chip inside.

It’s a shock to realise that nearly a quarter century has passed since then, and its fixed-focus 640×480 camera module with a UV-sensitive CMOS sensor that gave everything a slight blue tint would not even grace the cheapest of feature phones in 2020. Every aspect of a digital camera has improved beyond measure since the first models in the 1980s and early 1990s that started to resemble what we’d know today as a standalone digital camera, they have near-limitless storage, excellent lenses, huge and faithfully-reproducing sensors, and broadcast-quality video capability.

But how playful have camera manufacturers been with the form factor? We see reporters in sci-fi movies toting cameras that look nothing like their film-based ancestors. What do our real-life digital cameras have on offer as far as creative body design goes?

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A Hot Printer For Cool Selfies

Randomly buying some hackable gadgets just because they are cheap and seem potentially interesting for future projects is something that most of us can relate to. It also happened to [fruchti] when he bought five thermal printer modules without any specific purpose for them in mind. It was not until several years later that he put them to good use for his inverse thermal camera project.

The name perfectly summarizes the device’s function which is to convert images to heat instead of the other way around. To put it in a less cryptic manner, [fruchti] built a selfie camera that instantly prints out pictures on thermochromic paper. The project would have been easy to implement on a Raspberry Pi but instead, he chose a more minimalist approach by using an STM32 microcontroller. This involved some challenges because the MCU didn’t have enough RAM to store an entire frame and the camera module came without a FIFO buffer. To capture and store the image data [fruchti] applied a line-by-line dithering algorithm which is described in detail in his accompanying blog post while the corresponding code is available on GitHub. Even though the case was improvised from scrap PCB materials the finished device still looks great. In particular, the fuse holders that are being used to hold the paper roll make it almost steampunk.

Naturally, this is not the first time we have seen thermal printers being used for instant picture taking and it probably won’t be the last.