Cameras are a funny rabbit hole to fall down as a hacker, because we have well over a century of items to pick and choose from, a lot of which can be had for relative pennies. In my case I have more of them than I’d care to mention, mostly film cameras and 8mm movie cameras, but there are one or two that are entirely different. My first interest in electronics came through PAL televisions, so it’s hardly surprising that along the way I’ve also acquired more than one chunky old tube-based video camera. These devices are now long ago supplanted by their solid state replacements, but they retain a fascination for me as the mirror of the CRT-based TV sets I know so well. It’s time for a fascinating descent into the world of analogue video.

Electrons chasing light, chasing electrons

The basic mode of operation behind all but some of the very earliest electronic camera tubes is that an electron gun paints its raster of electrons onto a light-sensitive target, and the current flowing through the electron beam varies in proportion to the light at each particular point on the target. This can be used to create a voltage, which when combined with the various sync pulses makes a video signal that would be understood by a monitor. The various different types of tubes have names such as Iconoscope, Emitron, or Vidicon, and while the main differences between those various types of tube lie in the combination of materials and design of their targets. Successive generations of tube made improvements to sensitivity and noise performance, first combining photoemissive layers with electron multiplying layers to amplify the video signal in much the same way as a photomultiplier tube does, and then using photoconductive targets to vary the conductivity of the target depending on the light at a particular point.

Time for some real cameras

The tube camera I’ve owned the longest is probably the best to have the lid off and see its internals, it’s an RCA security camera from the mid 1980s. Very sturdily built in the USA, mine is the 625-line version for the European market. Opening it up there’s another echo of the CRT monitor, with the same deflection and signal panels you’d find at the other end of the chain. On top is a sync generator panel, which is far more than a simple pair of oscillators. Instead it’s stuffed with circuitry to produce the full standard sync timings with odd and even fields. Lifting out the sync panel reveals the tube, in this case a vidicon with a photoconductive target, encased in its magnetic focus and deflection coils. This is a monochrome camera, so everything is pretty easy to understand.

When a colour analogue video camera is explained, it usually starts with a diagram of a light path with a couple of bean splitters and a set of filters to supply red, green, and blue images to three different tubes. This produced those high quality broadcast images, but at the expense of significant expense and complexity. As colour home video equipment appeared in the 1970s there appeared a demand for single-tube colour cameras, and to that end the manufacturers came up with a variety of similar tubes with RGB stripe filters over their targets. A couple of these cameras have come my way, both of which have Panasonic Newvicon tubes. These differentiate between red, green, and blue parts of the image by their amplitudes, and while the image is definitely colour, I’d be lying if I said it was broadcast quality.

Here in 2024 there’s very little reason to use a tube camera unless as I am you are seeking a partcular aesthetic, That said, they remain a fun and forgotten piece of consumer electronics to experiment with, so pick one up and have a play should you see one. Looking at the whole system of both camera and monitor it’s possible to see the beauty of analogue television, in the way that every part of the system exists in perfect synchronisation. Imagine the TV sets of a whole country tuned to the same channel, and all synchronised to within a fraction of a microsecond, and you’ll see what I mean even though the idea of everyone watching the same show together is now more than faintly ridiculous.

If this has tickled your fancy, here’s more from the PAL coalface.

Header: Kyle Senior, CC BY-SA 4.0.

Over the decades the video and music industries have tried a wide range of ways to get consumers to buy ‘cheaper’ versions of albums and music, but then limit the playback in some way. Perhaps one of the most fascinating ones is the 2View, as recently featured by [Matt] over at Techmoan on Youtube. This is a VHS tape which works in standard VHS players and offers you all the goodness that VHS offers, like up to 512 lines of PAL video and hard-coded ads and subtitles, but also is restricted to just playing twice. After this second playback and rewinding, the tape self-erases and is blank, leaving you with just an empty VHS tape you can use for your own recordings.

As a form of analog restrictions management (ARM) it’s pretty simple in how it works, with [Matt] taking the now thankfully erased Coyote Ugly tape apart for a demonstration of the inside mechanism. This consists out of effectively just two parts: one plastic, spring-loaded shape that moves against one of the tape spools and follows the amount of tape, meaning minutes watched, and a second arm featuring a permanent magnet that is retained by an inner track inside the first shape until after rewinding twice it is released and ends up against the second spool, erasing the tape until rewound, after which it catches in a neutral position. This then left an erased tape that could be safely recorded on again.

Although cheaper than a comparable VHS tape without this limit, 2View was released in 2001, when in the Netherlands and elsewhere DVDs were demolishing the VHS market. This, combined with the fact that a simple bent paperclip could be stuck inside to retain the erase arm in place to make it a regular VHS tape, meant that it was really a desperate attempt that quickly vanished off the market

Long before we had internet newsfeeds or Twitter, Ceefax delivered up-to-the-minute news right to your television screen. Launched by the BBC in 1974, Ceefax was the world’s first teletext service, offering millions of viewers a mix of news, sports, weather, and entertainment on demand. Fast forward 50 years, and the iconic service is being honored with a special exhibition at the Centre for Computing History in Cambridge.

At its peak, Ceefax reached over 22 million users. [Ian Morton-Smith], one of Ceefax’s original journalists, remembers the thrill of breaking stories directly to viewers, bypassing scheduled TV bulletins. The teletext interface, with its limited 80-word entries, taught him to be concise, a skill crucial to news writing even today.

We’ve talked about Ceefax in the past, including in 2022 when we explored a project bringing Ceefax back to life using a Raspberry Pi. Prior to that, we delved into its broader influence on early text-based information systems in a 2021 article.

But Ceefax wasn’t just news—it was a global movement toward interactive media, preceding the internet age. Services like Viditel and the French Minitel carried forward the idea of interactive text and graphics on screen.

Making microcontrollers produce video has long been a staple of hardware hacking, but as the resolution goes up, it becomes a struggle for less capable silicon. To get higher resolution VGA from an Arduino, [Marcin Chwedczuk] has produced perhaps the most bulletproof solution, to create dual-port RAM with the help of a static RAM chip and a set of 74-series bus transceivers, and let a hardware VGA interface take care of the display. Yes, it’s not a microcontroller doing VGA, but standalone VGA for microcontrollers.

Dual-port memory is a special type of memory with two interfaces than can independently be used to access the contents. It’s not cheap when bought in integrated form, so seeing someone making a substitute with off-the-shelf parts is certainly worth a second look. The bus transceivers are in effect bus-width latches, and each one hangs on to the state while the RAM chip services each in turn. The video card part is relatively straightforward, a set of 74 chips which produce the timings and step through the addresses, and a shift register to push out simple black or white pixel data as a rudimentary video stream. We remember these types of circuits being used back in the days of home made video terminals, and here in 2024 they still work fine.

The display this thing produces isn’t the most impressive picture, but it is VGA, and it does work. We can see this circuit being of interest to plenty of other projects having less capable processing power, in fact we’d say the challenge should lie in how low you can go if all you need is the capacity to talk 74-series logic levels.

Interested in 74-series VGA cards? This isn’t the first we’ve seen.

[Ryan Miceli] had spent a few years poring over and reverse-engineering Halo 2 when a friend asked for a favor. His friend created an improved Xbox with significant overclocks, RAM upgrades, BIOS hacks, and a processor swap. The goal was simple: patch the hardcoded maximum resolution from 480p to 720p and maybe even 1080p. With double the CPU clock speed but only a 15% overclock on the GPU, [Ryan] got to work.

Step one was to increase the size of the DirectX framebuffers. Increasing the output resolution introduced severe graphical glitches and rendering bugs. The game reuses the framebuffers multiple times as memory views, and each view encodes a header at the top with helpful information like width, height, and tiling. After patching that, [Ryan] had something more legible, but some models weren’t loading (particularly the water in the title screen). The answer was the texture accumulation layer. The Xbox has a hardware limitation of only sampling four textures per shader pass, which means you need a buffer the size of the render resolution to accumulate the textures if you want to sample more than four textures. Trying to boot the game resulted in an out-of-memory crash. The Xbox [Ryan] was working on had been upgraded with an additional 64MB of RAM, but the memory allocator in Halo 2 wasn’t taking advantage of it. Yet.

To see where the memory was going, [Ryan] wrote a new tool called XboxImageGrabber to show where memory was allocated and by whom. Most games make a few substantial initial allocations from the native allocator, then toss it over to a custom allocator tuned for their game. However, the extra 64MB of RAM was in dev consoles and meant as debug RAM, which meant the GPU couldn’t properly access it. Additionally, between the lower 64MB and upper is the Xbox kernel. Now, it became an exercise of patching the allocator to work with two blobs of memory instead of one contiguous one. It also moved runtime data into the upper 64MB while keeping video allocations in the lower. Ultimately, [Ryan] found it easier to patch the kernel to allow memory allocations the GPU could use in the upper 64MB of memory. Running the game at 720p resulted in only a semi-playable framerate, dropping to 10fps in a few scenes.

After some initial tests, [Ryan] concluded that it wasn’t the GPU or the CPU that was the bottleneck but the swap chain. Halo 2 turns VSync on by default, meaning it has to wait until a blank period before swapping between its two framebuffers. A simple tweak is to add a third frame buffer. The average FPS jumped 10%, and the GPU became the next bottleneck to tweak. With a light GPU overclock, the game was getting very close to 30fps. Luckily for [Ryan], no BIOS tweak was needed as the GPU clock hardware can be mapped and tweaked as an MMIO. After reverse engineering, a debugging feature to visual cache evictions, [Ryan] tuned the texture and geometry cache to minimize pop-ins that the original game was infamous for.

Overall, it’s an incredible hack with months of hard work behind it. The code for the patch is on Github, and there’s a video after the break comparing the patched and unpatched games. If you still need more Halo in your life, why not make yourself a realistic battle rifle from the game?

[Scott] has a neat little closet in his carport that acts as a shelter and rest area for their outdoor cat, Rory. She has a bed and food and water, so when she’s outside on an adventure she has a place to eat and drink and nap in case her humans aren’t available to let her back in. However, [Scott] recently noticed that they seemed to be going through a lot of food, and they couldn’t figure out where it was going. Kitty wasn’t growing a potbelly, so something else was eating the food.

So [Scott] rolled up his sleeves and hacked together an OpenCV project with a FLIR Boson to try and catch the thief. To reduce the amount of footage to go through, the system would only capture video when it detected movement or a large change in the scene. It would then take snapshots, timestamp them, and optionally record a feed of the video. [Scott] originally started writing the system in Python, but it couldn’t keep up and was causing frames to be dropped when motion was detected. Eventually, he re-wrote the prototype in C++ which of course resulted in much better performance!

It didn’t take long to nab the thief — actually, thieves! It seemed quite a few different local animals had discovered Rory’s shelter and were helping themselves to her food. How rude! The first night detected a few different visitors. First, Rory’s local “boyfriend” stopped by to have a snack. Then within half an hour, an opossum (or possibly a small raccoon?) scarfed down what food was left. And within fifteen minutes of that visitor, a raccoon stopped by and was disappointed all the food was gone. Then, early in the morning. Rory arrives and is aghast that all her food is missing — again!

After analyzing all the footage, the solution, for now, is to feed Rory wet food twice a day and put just a little bit of kibble in her closet bowl in the morning for her to snack on throughout the day. In the future, [Scott] might use an RFID door to keep others out (though raccoons can be very smart and might be able to rip the door open), or possibly even something as simple as a magnetic collar and a Hall effect sensor to open the door or dispense food. Either way, the important thing is Rory is a happy cat and OpenCV rocks!

We love hearing about a good experiment, and here’s a pretty neat one: researchers used a VR headset, an off-the-shelf VR360 camera, and some custom software to glue them together. The result? Owl-Vision squashes a full 360° of un-distorted horizontal visual perception into 90° of neck travel to either side. One can see all around oneself, without needing to physically turn one’s head any further than is natural.

It’s still a work in progress, and accessing the paper currently doesn’t have a free option, but the demonstration video at that link (also embedded below) gives a solid overview of what’s going on.

The user wears a VR headset with a 360° camera perched on their head. This camera has a fisheye lens on the front and back, and stitches the inputs together to make a 360° panorama. The headset shows the user a segment of this panorama as a normal camera view, but the twist is that the effect from turning one’s head is amplified.

Turning one’s head 45 degrees to the left displays as though one’s head turned 90 degrees, and turning 90 degrees (i.e. looking straight left) displays the view directly behind. One therefore compresses an entire 360 degrees of horizontal visual awareness into the normal 180 degree range of neck motion for a person, without having to resort to visual distortions like squashing the video.

In a way this calls to mind the experiments of American psychologist George Stratton, whose fascinating work in visual perception involved wearing special eyeglasses that inverted or mirrored his sight. After a few days, he was able to function normally. Owl-Vision seems very much along those lines, albeit much less intensive. It’s apparently quite intuitive to use, with wearers needing very little time to become accustomed. Messing with perception via VR has gone the other way, too. Adding lag to real life is remarkably debilitating for interactive tasks.

The short video demo for Owl-Vision also includes a driving simulator demo in which the driver shows off the ability to look directly behind themselves with ease.

[Video: Owl-Vision: Augmentation of Visual Field by Virtual Amplification of Head Rotation, Augmented Humans International Conference 2024]