There were loads of addons and I/O projects. For just a taste, take a look at eg Usborne's "How to make Computer Model Controllers" from https://usborne.com/gb/

There were loads of addons and I/O projects. For just a taste, take a look at eg Usborne's "How to make Computer Model Controllers" from https://usborne.com/gb/books/computer-and-coding-books https://usborne.com/gb/books/computer-and-coding-books (Direct link: https://drive.google.com/file/d/1FqhExLPJZHakw6RpNr_LKtmtk1hNaTZ8/view https://drive.google.com/file/d/1FqhExLPJZHakw6RpNr_LKtmtk1h...) Or the works of R.A.Penfold