Tiny Datasette Uses USB For The Modern Day

While you can still find tape being used for backup storage, it’s pretty safe to say that the humble audio cassette is about as out of date as a media format can be. Still, it has a certain retro charm we’re suckers for, particularly in the shape of a Commodore Datasette. We’re also suckers for miniaturization, so how could we not fall for [bitluni] ‘s tiny datasette replica?

Aesthetically, he’s copying the Commodore original to get those sweet nostalgia juices flowing, but to make things more interesting he’s not using compact cassette tapes. Instead, [bitluni] started with a mini cassette dictaphone, which he tore down to its essentials and rebuilt into the Commodore-shaped case.

The prototyping of this project was full of hacks — like building a resistor ladder DAC in an unpopulated part of a spare PCB from an unrelated project. The DAC is of course key to getting data onto the mini-casettes. After some playing around [bitluni] decided that encoding data with FSK (frequency-shift keying), as was done back on the C-64, was the way to go. (Almost like those old engineers knew what they were doing!) The dictaphone tape transport is inferior to the old Datasette, though, so as a cheap error-correction hack, [bitluni] needed to duplicate each byte to make sure it gets read correctly.

The mini cassettes only fit a laughable amount of data by modern standards this way (about 1 MB) but, of course that’s not the point. If you jump to 11:33 in the video embedded below, you can see the point: the shout of triumph when loading PacMan (all 8 kB of it) from tape via USB. That transfer was via serial console; eventually [bitluni] intends to turn this into the world’s least-practical mass storage device, but that wasn’t necessary for proof-of-concept. The code for what’s shown is available on GitHub.

If you have an old Datasette you want to use with a modern PC, you’d better believe that we’ve got you covered. We’ve seen other cassette-mass-storage interfaces over the years, too. It might be a dead medium, but there’s just something about “sticky tape and rust” that lives on in our imaginations.

Thanks to [Stephen Walters] for the tip.

5 thoughts on “Tiny Datasette Uses USB For The Modern Day

  1. Using something like v.92 modulation you could perhaps get 9 megabytes out of a 60 minute cassette tape at 56 kbps using both stereo channels. With an even better modulation scheme you could make use of more of the audio bandwidth of about 10-15 kHz, giving 200 kbps and perhaps up to 120 megabytes for two channels for a 60-minute tape.

    1. The very best music-rated microcassette recorder mayyybe got up to 9 or 10kHz (yes they existed! Super cool stuff!) but if it’s a dictaphone tape mechanism, if you reach 4kHz mono you should be very happy.

Leave a Reply

Please be kind and respectful to help make the comments section excellent. (Comment Policy)

This site uses Akismet to reduce spam. Learn how your comment data is processed.