I remember when i was a kid, i was just starting with electronics, and i was very curious about this kind of systems. They were present in every contest show on tv. It’s cool that someone developed and published a project like this. The system is controlled by an ATmega88, and the voting pads interconnect trough RS-485. After the voting is done, a Java application that runs on the PC generates bar graphs.
Voting Pads System based on ATmega88: [Download Project] – [View Project PDF] – [Via]