Bubbles, Belts, and Bulbs: How the Scantron Works
Many of us remember back in our school days taking tests and filling out answers on a Scantron sheet, those long rows of A, B, C, D, and E that …read more
https://hackaday.com/2026/07/02/bubbles-belts-and-bulbs-how-the-scantron-works/