A lot of projects we feature use video in some form or other, but that video is invariably digital, it exists as a stream of numbers in a computer memory or storage, and is often compressed. For some of us who grew up working with composite video there is a slight regret that we rarely get up-close and personal with an analogue stream, so [Kris Slyka]’s project putting video on a conventional audio cassette is a rare opportunity. (Video, embedded below.)
Readers with long memories may recall the Fisher-Price PixelVision toy from the late 1980s which recorded black-and-white video on a conventional cassette running at many times normal speed. This system does not take that tack, instead it decreases resolution and frame rate to a point at which it can be recorded at conventional cassette speeds. The result is not particularly high quality, but with luminance on one side of a stereo recording and chrominance on the other it does work.
The video below the break is a run through the system, with an explanation of how video signals work. Meanwhile the code for both encoder and decoder are available through the magic of GitHub. If you’re interested further, take a look at our examination of a video waveform.
After freeing the tape mechanism from the original enclosure and extraneous electronics like the AM/FM tuner, [Igor] got to work designing a retro styled enclosure for the hardware which would show off the complex electromechanical bits which would traditionally be hidden. With the addition of a clever 3D printed holder, he was even able to add microswitches under the original player’s buttons so he could detect the player’s current state without having to modify the electronics. This lets the finished player change the color of the RGB LEDs based on what it’s currently doing.
[Igor] came up with a very clever way of integrating light-up icons into the case by placing bright LEDs behind specially crafted thin sections of the print. It looked awesome in his tests, but after the considerable sanding, priming, and painting it took to turn the 3D printed parts into a production-quality enclosure, the LEDs are no longer visible on the final product. Even though they didn’t work in this particular case, we think it’s a brilliant technique worthy of stealing further research.
The detail that [Igor] but into this build is phenomenal. Seeing all the individual components he had to design and print to make the final product come together is really nothing short of inspirational. Projects like these are where 3D printing really shines, as trying to replicate this build with traditional manufacturing techniques would be an absolute nightmare.
You should probably hope you haven’t seen [Techmoan’s] cassette recorder before. That’s because it is a Neal interview recorder that was mainly used by police to tape interrogations. This one was apparently used by the Royal Navy and was sold for parts. Turns out, the repair was simple, but the teardown and the analysis of the machine — you can see it in the video below — is pretty interesting if you’ve never seen one of these before.
The unit looks like a heavy-duty piece of industrial electronics from the 1980s. Unlike a commercial tape deck, this one is made to do one thing: record. You can’t even rewind a tape in it. Also unlike a consumer recorder, the Neal has a few special features aimed at making sure you didn’t miss some important confession on tape. First, it beeps if there’s no microphone plugged in. When [Techmoan] showed the recording head, we noticed it looked like it was split in half. Towards the end of the video, we found out why. In addition, the unit records two tracks: one audio track and another with a voice reading the elapsed time every 10 seconds — pretty high tech for its day.
As we’ve said many times here on Hackaday, it’s not our place to question why people make the things they make. There’s a legitimate need or utility for many of the projects we cover, no doubt about it. But there’s also a large number of them which are so convoluted that they border on absurd. Not that we love the crazy ones any less, in fact, we usually like those the best.
So when we saw this incredible modification to a Panasonic RN-404 microcassette recorder which replaces the audio hardware with a custom built vacuum tube amplifier, we didn’t bother asking what the point was. Perhaps it’s an attempt to make the most impractical method for recording and playing back audio, or maybe it was just to see if it was possible. No matter why it was done, it’s here now and it’s absolutely glorious.
If the look of the hardware didn’t tip you off that this project makes use of old Soviet-era components, the video after the break certainly will. Specifically, it’s using 1ZH25R and 1S38A tubes which were originally intended for military use. Just like all cool old Soviet tech was. Say what you will about the Cold War, it certainly got the engineering juices flowing.
There’s quite a bit of information about how these ancient tubes were brought back to life by way of this gorgeous home-etched PCB. Suffice to say, working with tubes is an art to begin with, but working with such small and unique ones is on a whole new level.
This isn’t the first time we’ve seen some tiny tubes make their way into a piece of consumer audio equipment, but this one certainly takes the top spot in terms of professional final results.
[Blaine Murphy] has set out to store an archive of visual art on cassette tape. To do so he encodes images via Slow-Scan Television (SSTV), an analogue technology from the late 50s which encodes images in for radio transmission. If you are thinking ‘space race’ you are spot on, the first images of the far side of the moon reached us via SSTV and were transmitted by the soviet Luna 3 spacecraft.
Encoding images with 5os technology is only one part of this ongoing project. Storage and playback are handled by a 90s tape deck and the display unit is a contemporary Android phone. Combining several generations in one build comes with its own set of challenges, such as getting a working audio connection between the phone and the tape deck or repairing old consumer electronics. His project logs on this topic are solid contenders for ‘Fail Of The Week’ posts. For instance, making his own belts for the cassette deck was fascinating but a dead end.
The technological breadth of the project makes it more interesting with every turn. Set some time aside this weekend for an entertaining read.
8bit Mixtapes are simple Arduino-based sound and beat generators based on ATtiny 84s and 85s and designed fit inside old audio cassettes, or at least be about that size. Founded by [Dusjagr], [Ucok] and [Lyok], and including participants from around the globe, 8bit Mixtapes are small synthesizers that play one-line algorithmic symphonies, simple sound generators that work off of a single line of code.
The project has been going on for a number of years, with several different iterations released over the years–the most recent is the Mixtape NEO, released about a month ago that features audio bootloading and a row of NeoPixel LEDs. It’s well documented and fully open source, with a code repository and wiki. The arty PCBs look great as well!
8bit Mixtapes are a natural project for electronics students to tackle. An ATtiny85 with two pots and two buttons? Pretty simple, and the musical payoff makes it a cinch for one-day workshops. The code simplicity makes it easy to modify the software as well.
The audio cassette is an audio format that presented a variety of engineering challenges during its tenure. One of the biggest at the time was that listeners had to physically remove the cassette and flip it over to listen to the full recording. Over the years, manufacturers developed a variety of “auto-reverse” systems that allowed a cassette deck to play a full tape without user intervention. This video covers how Akai did it – the hard way.
Towards the end of the cassette era, most manufacturers had decided on a relatively simple system of having the head assembly rotate while reversing the motor direction. Many years prior to this, however, Akai’s system involved a shuttle which carried the tape up to a rotating arm that flipped the cassette, before shuttling it back down and reinserting it into the deck.
Even a regular cassette player has an astounding level of complexity using simple electromechanical components — the humble cassette precedes the widespread introduction of integrated circuits, so things were done with motors, cams, levers, and switches instead. This device takes it to another level, and [Techmoan] does a great job of showing it in close-up detail. This is certainly a formidable design from an era that’s beginning to fade into history.
The video (found after the break) also does a great job of showing glimpses of other creative auto-reverse solutions — including one from Phillips that appears to rely on bouncing tapes through something vaguely resembling a playground slide. We’d love to see that one in action, too.