I always suspected this to be possible and I finally got around to doing it. By creating a barcode of my username, a "tab," and my password, I can now login to my website by simply using a barcode scanner. I expect this to be useful as we transition into using UberPOS as our point of sales system at left-click. Cashiers can have an ID card with one of these barcodes on it allowing them to scan it and login. For now, I've affixed my login barcode to my USB stick.
After a lot of searching, and digging too deep into how barcodes are generated, this link was found. There they have an online barcode generator with the special feature of allowing you to have ASCII key codes, such as the Tab key, encoded into the barcode. The winning combo for getting this generator to produce a login barcode was: