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Could a person develop a homebrew physical media format and player-drive for either audio/video or data? Can this be theoretically done?

Anything is possible.

My interest in it was curiosity.

There are several people who have made Arduino-based punch card readers. Theoretically this could be considered a custom format.
However, it's rather hard to "write" to the punch card with an Arduino, and practically impossible to "re-write."

It would probably be pretty easy to connect it to a Raspberry Pi (or like)'s GPIO pins and write a "driver" for it to read the data.
It might even be possible to create an interface for an x86-based computer somehow (not recommended: could potentially fry your machine).

Of course, this media wouldn't be nearly fast enough to be used to store audio or video. You'd probably just be storing text or other data.

Magnetic media or flash memory would be much harder to make at home.

foliagecanine wrote:There are several people who have made Arduino-based punch card readers. Theoretically this could be considered a custom format.
However, it's rather hard to "write" to the punch card with an Arduino, and practically impossible to "re-write."

Yeah, I've found plenty of homemade paper tape / card reader projects online, but I'm not sure I've found one project for a ground-up punch (there are a few for restoring old punches). But the difficulties in making a punch would primarily be mechanical, I wouldn't expect the Arduino programming (or whatever controller you're using) to be that much more difficult.

I've wondered about whether in the modern day it might be easier to use something like a receipt printer (though printing on something a bit thicker than receipt stock to reduce the likelyhood of tearing/crumpling in handling or tearing/crumpling/jamming in the reader). You'd just print black squares instead of punching (if you were doing cards rather than tape, you might opt to use an existing QR code format of appropriate dimensions and capacity). It seems like it should be doable to frankenstein an Arduino to some sort of existing printing hardware to create a card or tape "punch". "Rewriting" would basically have to be done by appending a diff to the end of a tape/card data set.

Magnetic media ... would be much harder to make at home.

A hard disk certainly would be. I'm less certain about floppy or tape media. Especially tape. Putting together a homemade drive, getting some kind of dust jacket onto the disk, and making sure everything was rotationally balanced would be a pain for a floppy, but tape should be much simpler to deal with mechanically, and I'm pretty sure that the ingredients for the actual medium itself for a floppy or magnetic tape are just plastic film, glue, and finely powdered rust. One might not achieve the storage densities for homemade tape that one would for professionally manufactured tape, but it seems like one of the more home-manufacturable media. Mechanically and electronically it would probably be *easier* than any kind of punch/printer for paper storage, the big issue would be manufacturing the tape itself. Audio cassettes are even making a comeback due to music nostalgia, and cartridge magtape is still very much in use for datacenter backup storage, so:

1) A lot of the old 8-bit home computers used an audiocassette in an off-the-shelf tape player for storage (the user had to start and stop the tape himself). All this requires is an audio jack and a driver to modulate/demodulate the audio signal.
2) One could frankenstein an Arduino to a tape player to get a drive with automatic start/stop/rewind.
3) One could purchase audiocassettes and strip the tape out for use in a format convenient to the user.
4) One could potentially buy audiotape straight (without a cassette), though my understanding is that most cassette manufacturers these days are manufacturing tape in-house, not outsourcing, so finding audiotape outside of a cassette may be difficult.
5) Depending on use case, one might just buy a tape drive and a stock of tape cartridges. Or, one might figure out how to frankenstein a tape drive (if you're trying to use it with an old machine that doesn't have modern storage ports, or something that you cobbled together on a breadboard, or whatever).

linguofreak wrote:2) One could frankenstein an Arduino to a tape player to get a drive with automatic start/stop/rewind.

Ooh boy... one would need an old tape mechanism for this, one that is soft-touch capable. They did exist in the 80ies, but the only tape mechanism still being made today is not soft-touch capable. It is a highly-integrated unit that actually requires the physical movement of the buttons to achieve their actions; it is not a case where you could just close some electric contacts. If you were to use that mechanism, you would need servos to physically press the buttons. Or maybe solenoids would work.

And the old tape mechs, that are soft-touch capable, well, they would only be present in old mid-to-high-end HiFi systems, which at the moment are sold on ebay for ungodly prices.

Actually, I did think about building a floppy drive myself, since all 5 1/4" drives I know seem to be failing, and there are no 5 1/4" drives being made for USB, and I once wanted to rectify this. But I really don't know the first thing about magnetic media. To my knowledge, the actual read/write head is an electromagnet, and I have no idea how to make one so small. And then I would have no idea how to transform that waveform that's coming from the head into actual data. I guess I could search for documentation, but the effort is just too much for an idea that does not go beyond "neat".

And even then, I just wanted to build something that already used to exist, not create something entirely new. I have absolutely no idea why you would want to do that. I mean I have a 32GB transportable medium that is smaller than the nail of my pinkie (a micro-SD card), and even fixed storage is getting (physically) really small now, and (storage-wise) really big at the same time. 1 TB M.2 drive anyone? It's gotten to the point where there are computer cases entirely lacking the space to put hard-drives or optical media of any kind, because people stopped using those.

nullplan wrote:To my knowledge, the actual read/write head is an electromagnet, and I have no idea how to make one so small.

Just a heads up, I have no idea whether this is how they do it or whether this even works at all, but...

Have you ever made a "paper clip chain" by attaching a paperclip to a magnet, then attach another paper clip to that paper clip, etc.
The paper clip in effect "channels" the electromagnetic field. So, this might work with a needle or something to get to a very small area. This might work for writing bits.
I think reading it would be much harder though, since the electromagnetic field of the bits are so small. You'd have to get the sensor REALLY close to it.

Anyways, just a random idea I had.

This thread reminds me of Star Trek where Spock says:

I'm Attempting To Construct A Mnemonic Memory Circuit, Using Stone Knives And Bearskins.

nullplan wrote:

linguofreak wrote:2) One could frankenstein an Arduino to a tape player to get a drive with automatic start/stop/rewind.

Ooh boy... one would need an old tape mechanism for this, one that is soft-touch capable. They did exist in the 80ies, but the only tape mechanism still being made today is not soft-touch capable. It is a highly-integrated unit that actually requires the physical movement of the buttons to achieve their actions; it is not a case where you could just close some electric contacts. If you were to use that mechanism, you would need servos to physically press the buttons. Or maybe solenoids would work.

The soft-touch capable mechanism would just give you your servos prepackaged, it would still have to have them. IIRC, tape players unmounted the tape for fast forward and rewind, so you'd need something to drive the mount/unmount action. You wouldn't need to add a servo for eject, that could remain user-powered (as it generally did for floppy drives).

Seasoft wrote:Could a person develop a homebrew physical media format and player-drive for either audio/video or data? Can this be theoretically done?

Yyeess... I think most of the issues have been covered. On the physical side, you'd probably get more info on a maker forum.

I've thought of messing about with tapes, particularly storing data on the old 8-track audio format or on videocassettes. The latter has actually been done, but not by me. It's tricky because the read-write head scans diagonally across the tape, but it also means the use of the media is maximized. I kind-of gave up thinking about it when I learned even professional data tape systems are not considered very reliable. VHS tapes didn't really last very long in their normal use, particularly because the spinning head wasn't terribly good for the tape. Capacity... I've forgotten half the stuff I'd need to know for a quick calculation, but don't expect to really challenge modern disc drives.

I remember a couple of bits about data on audio casettes. It was normally stored with an FM encoding. There's only about 60dB separation between the stereo channels; too little to really use them to double the data capacity/rate. However, you could probably get 1.5x or more by encoding the different channels with different frequencies. Or you could put different frequencies on the same channel and use a mono head. I once heard mono heads could read & write more reliably, which is probably true. (Didn't stop Atari from using a stereo head. *shrug*) Do note that audio tape has a surprisingly low bandwidth. Atari cassettes only stored 600 bits/second.

Or... you could go *right* back to the beginning of magnetic recording and build your own hardware to record onto steel wire.

You could also record data with a vibrating stylus on vinyl discs or even wax cylinders. I never learned the details of the recording hardware for those.

You could hypothetically build something to record data with a laser on optical film, but you'll need a very good workshop to get the kind of data density monochrome film is capable of holding. And you'd need to develop the film with chemicals and trays and a special dim red light... unless you automated that too.

Oh... no-one's covered making your own tape drive, have they? It's do-able, not terribly high-tech. I don't think you'll need very high-precision tools by modern standards, but you might for the heads themselves. You will need some semi-specialist knowledge, like making sure the drive belts can slip or you'll break the tape.

Making your own tapes and discs must also be possible. I'm pretty sure they're just a fine grade of iron filings in a soft medium on a flexible (or sometimes hard) substrate. So yes, making your own media format is quite possible.