Weewees alarm clock

Needing the toilet is one of the most effective ways of being woken up, therefore, the weewees alarm clock manually alters the time at which nature calls.
Obviously the alarm can't be entirely accurate, but the veracity can be improved provided the device knows the user's body mass, and age (Assuming normally functioning organs, and a freshly empty bladder at time of setting the alarm).
The alarm must be set for the chosen wake up time, and the calculate button pressed just as the user is going to bed - this will tell how much water should be drunk to wake up at approximately the right time (and, provided the deluxe version was bought - will dispense it from the resevoir).
If an important engagement hinges on waking up on time, it is suggested that an extra half glass of water be drunk - or simply return to the more conventional noisy alarm clock.