Abstract: The invention concerns a device for detecting a body falling in a volume of water (20) of a pool comprising a probe (1) adapted to transmit aquatic waves propagated in the pool (20) and an electronic unit (4) adapted to receive and interpret electric signals representing pressure variations caused by the aquatic waves received by the probe. The probe (1) has a free end (11) immersed in the pool (20) and a substantially vertical axis (12). The device further comprises an immersed rigid obstacle (3) extending between the immersed end of the probe and the surface of the volume of water of the pool in a plane substantially perpendicular to the axis of the immersed probe. The rigid obstacle (3) enables disturbances caused by the surface waves to be eliminated from the measurements of pressure variations caused by the aquatic waves in the probe (1).

Abstract: The invention relates to a device enabling an alarm to be triggered in the event of a fall into a swimming pool, and preventing false alarms caused by disturbing elements such as the wind. Said device consists of a probe (1) which is submerged in the liquid used to retransmit the aquatic waves varying in pressure in the compression chamber (8), a piezoelectric-type sensor (2) which is located inside said chamber and used to convert the pressure variations into electrical voltage, another identical sensor (3) located in the housing (7) and enabling the electronic card (4) to substract the two sets of information enabling the vibrations, in addition to the noise caused by the wind on the housing, to be eliminated, and an electronic card (4) which is used to control a siren for alerting the parents. The inventive device can optionally pilot a radio emitter (5) for controlling a deported siren.