Safety device for underwater diving

1. A safety device comprising:

a portable acoustic sensor for measuring an acoustic signal representative of a quantity of bubbles in a body of a person;

a portable pressure sensor for measuring ambient pressure;

at least a fixing device adapted to hold said acoustic sensor and said pressure sensor on said person; and

a computer adapted to receive bubble information and pressure information from said acoustic sensor and said pressure sensor, and to modulate a duration of at least one decompression stop based on said bubble information and pressure information.

2. The device according to claim 1 , wherein the computer is adapted to calculate durations of decompression stops of a basic table of decompression, and a central processing unit is arranged to calculate modulations of said durations of decompression stops.

3. The device according to claim 2 , wherein the computer is arranged to modify and memorize said modulations of durations of decompression stops.

4. The device according to claim 1 , wherein the fixing device is arranged so that the acoustic sensor can be coupled to a vascular site of said person.

5. The device according to claim 1 , wherein the computer is adapted to communicate with the acoustic and pressure sensors through a wireless connection.

6. The device according to claim 1 , wherein the computer is arranged in order to provide an alarm signal through alarm means if the level of measured bubble importance exceeds a predetermined safety threshold.

7. The device according to claim 6 , wherein the computer comprises a wireless connection transceiver for exchanging said alarm signal with another safety device.

8. The device according to claim 6 , further comprising activating means for modifying the buoyancy of the device in case of said alarm signal.

9. The device according to claim 6 , further comprising activating means arranged to be activated by the computer in case of alarm to allow an inlet of safety gas in a breathing supply circuit of said person.

10. Use of a safety device according to claim 6 , wherein said fixing device is coupled to a body of a person housed in a decompression chamber, and a gradual reduction of an overpressure level is carried out in the chamber by monitoring said alarm means to temporarily slow down said reduction in case of alarm.

11. A system comprising a plurality of devices according to claim 1 and a database containing diving profiles and communicating with said computer for receiving temporal decompression profiles followed by different persons, said system being adapted to:

memorize said temporal decompression profiles in the database with indication of risky sections of the profiles; and

determine an envelope curve of the risky sections and memorize said envelope curves in the database.

12. A safety method comprising the following steps:

detecting by a portable acoustic sensor, an acoustic signal representative of a quantity of gas bubbles appearing inside a body of a person;

measuring said quantity of bubbles based on said acoustic signal;

measuring ambient pressure by a portable pressure sensor; and

transmitting bubble information and pressure information from said acoustic sensor and said pressure sensor into a computer and modulating in said computer, a duration of at least a decompression stop based on said bubble information and said pressure information.

13. The method according to claim 12 , further comprising providing an alarm signal through alarm means if the measured quantity of bubbles exceeds a predetermined safety threshold.

14. The method according to claim 12 , wherein said duration of said decompression stop is modulated according to a history of previous measurements of the quantity of bubbles.

15. The method according to claim 12 , wherein said duration of said decompression stop is modulated according to at least a current measures of the quantity of bubbles carried out in real time during said decompression stop.