Stage Timer

Counts up from zero on a black screen, then turns green, amber and red at the times you set.

Signal times

Green at

Amber at

Red at

Sound

Red keeps sounding until stopped

Flash the screen at each change

Hear the cues

On an iPhone: ringer on and volume up, or the cues stay silent. Tap Share then Add to Home Screen to launch it full-screen without Safari's bars.