Open post 13 @13@2137.social · Jul 03, 2026 13 @13@2137.social 2137.social Bubbles, Belts, and Bulbs: How the Scantron Works https://hackaday.com/2026/07/02/bubbles-belts-and-bulbs-how-the-scantron-works/ #ReverseEngineering #Acmotor #Automated #Scantron #School