Sensor is the most critical component of a bedwetting alarm. ToggleSmart is our newly developed sensor. Its design is innovative with an attempt to fix all the major deficiencies of the sensors available on the market. The main drawbacks of the sensors currently on the market are too easy to be dislodged; too difficult to be cleaned and too sharp which may damage clothing. Addressing these weaknesses, we have applied the technique of toggle clamp on our ToggleSmart which makes it easy to be attached securely to underpants. Despite its strong clamping force, ToggleSmart, unlike other traditional open-cover sensors, has no sharp teeth on cover which may cut the skin or damage clothes. As a modified open-cover sensor, ToggleSmart is very easy to clean and dry.