Presentation Timer is a small application intended to help academics and other people practice presentations with strict time limits.
It allows for up to two warnings to be displayed visually or audibly or both at any time during the presentation. The visual warning is modeled after how academic conferences warn presenters about how much time they have remaining.
Requirements about the presentation process at conferences were elicited from Jaana Eigi who provided valuable insights.
This is the JavaScript version that runs as a static single page app. You can see a live version here.