Figure 2 illustrates the three low levels of the water in the tank
that to be alerted. The three levels are called as low level, L1,
very low level, L2 and critical level L3. A signal is sent to each
detector circuit and sent notification to microcontroller when it
does not detect any water. From the microcontroller, the signal
is sent to GSM and to person in-charge in a form of SMS. There
are three sequences of SMS sent to the person in-charge to alert
the level of the water tank.