Paper ROM

This low-resolution memory device packs in just a few bytes of data. But it’s enough to spell out [Michael Kohn’s] name. He’s been experimenting with using paper discs for data storage.

His technique becomes immediately clear when you view the demo video below. The disc spins multiple times with the sensor arm reading one track. This gives the system the chance to measure the black band in order to get the data timing figured out. Once the outer track has been read the servo controlling the read head swings it to the next until all of the data is captured.

An Arduino is monitoring the QTR-1RC reflectance sensor which makes up the reading head. It uses the black band width in order to establish the size of an individual byte. Interestingly enough, the white parts of the disc do not contain data. Digital 0 is a black area 1/4 the width of the large black strip, and digital 1 is half as wide.

[Michael’s] set up the generator which makes the discs so that he can easily increase the resolution. The limiting factor is what the reading hardware is able to detect.

39 thoughts on “Paper ROM

    1. looks to me like an early example of what a disk style drive might of used at one point.

      i mean at one point someone could of desided the size of the negitive pulse or positive pulse could of been a 1 or a 0 witht he fliped gap being null/seporator.

      kind fo makes ya think dont it.

  1. No explanation needed, I immediately thought of bar codes when I saw the paper. Maybe something similar can be carve from wood or stone and use shadows & a light sensor to read data. Then we can plant a Super Mario ROM in the pyramids for giggles.

  2. I fail to see the point, if you want paper encoding why not use QR type codes?
    Also I would call not using the white ‘bizarre’ rather than ‘interesting’ :)

    Still, always nice to play around and try things I suppose, although even if I did try something like this I think I’d avoid the disc format.

  3. There are other nicer encodings for data than PWM. (MFM, GCR, Code128)…

    It’d be vaguely interesting to just directly print asynchronous serial and set it up mechanically to playback at 8N1 110bps or whatever you can get your serial port to do. At this servo’s 1.2s/revolution, that’d be ~13 bytes per track, and ~3 degrees per bit.

    1. What ya see up there would be considerd proof of consept.
      And alltho a strip would allow for possible faster or more storige in the same relitive volume a disk opens the path for RAD Random accsess data similer to the old HUGE ibm drives.

      Thin about it those drives in proof of consept one of them could of been this or darn nere to it.

      it’s all about what you have at hand.

      Makes you wonder how many early data devices were built like this in the lab before magnetic read heads were sed to be better.

      And then you wonder who saw an early prototype and whent BARCODE it can track our inventory

        1. He’s got a funny-sounding name, I’d guess he’s Eastern European. I’d also guess that his grasp of English is a lot better than your grasp of whatever his native language is. Sometimes foreigners speak with odd grammar, using bits of their own grammar in place of the English ones they’ve not learned properly.

          It’s forgiveable. I’m only a spelling and grammar Nazi with native English speakers.

  4. I understand this is just a proof of concept because barcode and QR style matrix code are better on every aspect. Depending on the application, even a magnetic card reader could be used…

      1. Heh. How about water in ice cube trays, with every compartment being a bit? You’d have to refresh every couple of days before the “charge” evaporates. (I always liked water analogies for electronics.)

  5. I suppose a music box drum could be considered ROM. An older amateur told me the IDer they built for the first FM repeater in this area was a metal disk with holes drilled in it to allow light to fall onto a photoresistor. punched hole paper ROM was used in some teletype applications I have been told.

    1. Entire reels of punch tape, boxes of punch cards, cards in perfect order that absolutely must not be mixed up or you’d be days without a working computer.

      This is all stuff that happened in the past, this is how we have computers NOW! Of course people used to store data on punched tape and cards. Punch-cards go back to the start of IBM before computers even appeared. They used mechanical tabulators, a horrible rack of pins and levers, to sort and process census data among other stuff. This is in the 1890s. When computers appeared and needed some data storage, punched holes in paper was the obvious solution.

      The first punch cards held encoded weaving patterns for Jacquard looms, 1801. Binary storage.

      But at one point all computers would load programs and data in through punched paper, either through the machine’s own reader / puncher, or through an attachment on a teletype machine. The tape worked on teletypes without computers (for form letters and mailmerging, all computerless), and on computers without teletypes. Magnetic storage came later.

      What are they TEACHING people these days?!?

    1. Depends how much data you want to store. Small amounts can use much simpler file systems. Invent your own! Have the AVR do the filing, or let the PC do it. You just need something, minimum I’d guess, that stores a file name (fixed 8.3 11 characters), location on the medium, and length. Keep a simple table of those at the beginning of your tape, and a record of where the table ends and raw files begin. Since it’s presumably write-once-only, you don’t need to worry about allocating space.

      Even simpler, have each file as a tape / whatever in itself. Write the name on in marker.

      A return to audio cassette would be a nice method for storing files. See how many MP3s you can fit on a C60!

  6. 1: The early teleGRAPH used a one line serial on a paper strip. Then operators found they could hear this serial code and interpret it directly.
    2: Player Pianos.
    3: Plans to store data on nano bumps on silicon or some stable mineral, as far a we are concerned… forever.

  7. he really should have done some research first. There are thousands of these kinds of paper data storage system out there. a simple webcam and a bit of software and he could quadruple his storage.

  8. As an exercise, I give him a lot of credit.. You can learn a lot of different things from this. It’s little projects like this that keep our coding and design skills sharp. Kudos, +1 to you

    1. Also halfway-decent turntables would have a tiny strobe light pointing at the side of the turntable. 3 sets of spaced marks, for 33, 45, and 78, and when it was turning at the right speed the relevant set of marks would look stationary.

  9. I was thinking about something similar to this the other day. This is a lot less complicated than the workings of an actually floppy drive, though it bears some similarity. Pretty cool that this guy actually made something.

  10. The tech museum in my city has an early magnetic storage from the 70s on display which is similar size to the one in the photo. It’s not a disk though, it’s a cylinder made out of paper of about 20cm radius, 15cm height and the top end capped so that the whole thing can spin on a needle placed in the center. It had 32kB capacity if I remember right.

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