Reasoning:
- Hard to sleep with alarms, which can wake one suddenly
- When sleeping with others in room, wish to not wake others up
- Some use smartphone under pillow to wake up, not necessarily good, health concern over
Requirements:
- Designed for room of about 20x20m
- Loud enough to wake user
- Quiet enough to not wake others
- Secondary: Design should be compact, with rechargeable power
