Design for Pool Alarm System Based on Pulse-width Anti-narrow

In order to reduce child drowning in the unattended ponds or swimming pools, a design method of a pool alarm system is proposed. The design of hydrophone probe was simplified by making the sealed probe model up of rigid plastic pipe, pond surface, piezoelectric ceramic and other elements. The influence on measurement accuracy caused by many factors such as vibration was weakened through adopting the differential equipment amplifier. The application scope of system was widened by using programmable amplifier. The alarm accuracy was increased and the miss rate was decreased because of adopting pulse-width anti-narrow filter. The experimental results indicate that the system has a good applicability and the accuracy of alarm is over 98%.