

My first job was extracting text from pdfs, in the end OCR was the most reasonable way. This was back in like 2010 when it was waaaaay harder.
Everyone who enjoys cosmic horror should read the PDF spec. https://pdfa.org/resource/pdf-specification-archive/
The hand wiring is really easy. It just takes a long time.
Basically it’s just a grid, and a diode per switch. Then you wire each column and each row into a microcontroller.
You can do it!