RandomTimer

An alarm sounds periodically after a random time exceeding a fixed threshold. You can set a fixed and a variable time and the app will wait for a random time between the fixed time and the sum of the fixed and variable time, then it will sound an alarm and restart the cycle until you stop it.
You can set the ringtone, the fixed and variable time, the respective maximum thresholds and choose whether to see the countdown or wait "blindly"