i have an idea that is a quiz contest buzzer system when a person presses the button earlier than other players even the button is pressed indicatiing that person has pressed the button earlier and rest of the players has pressed after him but light is not switched on . there is an ic used but i don,t know its name please if anyone search the project or tell me the name of ic.

 

You can make this your self with a pic or other micro controler, some led's and a buzzer. Its actualy the first project I designed from scratch when learning asm for the pic.

Sol

 

It's less confusing to open a new post for each subject.

There is a circuit for a quiz buzzer in the Projects Collection. Most contest buzzers use a microprocessor like the Z80.