I made this simple countdown timer that can do stuff when the time’s up, such as displaying a message, executing shell commands, or playing a sound. It also has a primitive function to loop the timer when it reaches zero.
I originally made this to alert me when I’m at the computer and a pizza’s in the oven so it wouldn’t get burned. 
Then I thought, this can be used as a tool to induce LD’s too, during one’s WILD attempt, by playing a sound every 10 minutes or so as a safety net in case you fall asleep.
I don’t know, maybe you’ll find it useful. Here it is anyway:
www.askoylan.com/grix/timer.exe
It includes a sample “Bell toll” .wav sound. Press F1 for basic instructions.