Tactile Clock vibrates the current time when the display is locked and the power button is pressed twice in a row with a delay between 50 and 1500 milliseconds. If the double click is performed accidentally while the display is still active, the app warns with a long, persistent vibration. The background process is started automatically after booting is finished.

Basically there exist two different vibration pattern: A short vibration stands for the digit 1 and a long one for the digit 5. So th