Yes, the interesting bit is not the Cosby sweater, but the interfacing of the knitting machine itself by emulation of a serial attached Tandy floppy drive.
The toughest part about this is hiring Bill Cosby to stand still while you knit a sweater of him. Then have Bill Cosby put on the sweater and stand still again.
They are $700 to $900 on eBay.
You use a Python proggy to emulate a Tandy floppy drive with the design from a 1-bit bitmap.