Do you have a parts list, etc for this? It reminds me of PET Computers with a casette drive.
Yeah! It works! Cassette to data, decoding in real time at 3k baud!
Some improvements to be made but super happy with this. This means I can encode a message to a cassette and then decode it without having to digitize the audio, as it's being digitized as it streams in.
So it could be nice for offline storage of sensitive data. This is the physical layer so of course its possible to add authenticated encryption as well.
For example you could leave a cassette at a dead drop with an ecash token on to pay your raw milk dealer.
The encoding mechanism is differential manchester encoding which means it should be more survivable on different cassette decks. I have some bad ones so I will test it.
In this short video I also explain it, although I think I mi's speak the band rate. It's 3k baud ish.
Tagging my electronics peeps: nostr:nprofile1qqsf37qcuu353dsyqaawqjdg8rr7vm7srchr76x9uqh3zfv2yuz07pqpzdmhxw309ucnydewxqhrqt338g6rsd3eq9z8wue69uhky6t5vdhkjmnjxejx2dtvddm8sdr5wpmkgmt6wfjxversd3sn2umevyexzenhwp3kzcn2w4cry7rsdy6kgatvvfskgtn0de5k7m30q9z8wue69uhk77r5wfjx2anpwcmrg73kx3ukydmcxeex5ee5de685ut2dpjkgmf4vg6h56n3w4k82emtde585u35xeh8jvn3vfskgtn0de5k7m30fmk7hw nostr:nprofile1qqs9l7uwrd4k98qwxjsp87ff36aswkde3g7jgq5ezcep6h45y4dkwdgprpmhxue69uhkxun9v968ytnwdaehgu3wwa5kuef0qys8wumn8ghj7mn0wd68ytn9d9h82mny0fmkzmn6d9njuumsv93k2tcpzpmhxue69uhk2tnwdaejumr0dshsph902p
Discussion
Link is below to the original blog post, github link is in that post.
So, the PET and others use a type of FSK. I tried that originally as well. It's not only slower but not as reliable I think.
I think perhaps it was easier to do fsk back then? Idk.
But in the discussion you'll see the benefits of manchester are I think we'll suited to this medium.
http://zeninstruments.blogspot.com/2021/10/manchester-decoder-and-cassette.html?m=1