It is a quiz buzzer that can use many smartphones.
I installed a quiz buzzer program on my smartphone.


Download the server program separately, install it on your computer and run it

When you access the server program on each smartphone

You can use your smartphone as a quiz buzzer.


Download server program QuizServer
http://sciencelove.com/1527


Only the first smartphone that was pressed first is activated, and the second and third smartphone users are shown at the bottom with a few seconds later.