Connect 2 devices, one to act as a display timer for speeches, one to control it
The setup requires 2 devices, one to act as the display, the other to control it as a remote. The devices are connected through wifi (though an internet connection itself is not necessary).
After connecting one device as the display, and one as the remote, the remote can set the duration of the timer with start/stop/reset functions, adjust the font size, and send popup messages as notifications to the speaker.