Up to now the personal safety of people involved in dangerous activities (for the human body) is insured by passive devices like hooks, ropes, safety barriers and other devices. Nowadays no an active device exists which is easy to wear, without any type of hassle, and which can automatically intervene during an accident, thus reducing or avoiding harm to the human body. The only patented device is a "personal airbag" for motorcyclists, which by means of a mechanical activator (cord connected to the motorcycle frame) protects the back of he who wears it in case he falls off whilst driving. If the wearer forgets to disconnect the cord before getting off the motorbike, the airbag will activate without unnecessarily necessity. Moreover, due to the nature of the mechanical activation, there is no possibility of inhibiting the device at low speed (or whilst stopped), when the protecting device is of no use. It has to be considered that for the device described above, a physical connection (string or whatsoever) between the device and a suitable fixing point (on the vehicle or other frame) is mandatory.
Otherwise the system could be manually activated, but in certain circumstances the manual activation could be very difficult or impossible (e.g. accident). The invention described here for which a patent is requested increases the safety level of the people staying (e.g. whilst working or involved in sport activity) in a potentially dangerous situations. The invention described is an intelligent device which monitors the motion of the person and which, in case of situations considered as dangerous, is immediately activated without any mechanical tie to frames or vehicles and without manual intervention. The said protection is performed by an inflatable overalls, or a "personal airbag", activated by an inertial platform which, by means of a special electronic circuitry analyses positions and accelerations of the body and predeceasing a real time intervention (in the order of a few milliseconds) in case the position and/or speed of the subject are greater than defined thresholds. The above described inertial platform is made of a sensor, which is able to measure the acceleration, gravity force and position on three orthogonal axes. After measuring the acceleration parameters, and performing the necessary computations, it can generate an electrical signal which can activate the inflate of safety devices (airbag, overalls, inflatable collar) which are worn by the person. In order to better clarify, the drawing shows a possible block diagram of the system.

The described device comprises one or more acceleration and trim sensors (1), a computing unit (2) connected to sensors (1) by means of analog to digital converters (3) able to generate trigger signals for the safety devices when the values measured by the sensors (1) are outside a prefixed range, typical of the particular application; all the constants relevant to the application are stored into the computing unit (2). The sensors (1) are connected to the analog to digital converter (2) via a suitable conditioning circuitry, and are processed elaborated by the microprocessor (2) and stored in its working memory (4) (RAM).
The I/O device (5) enable the operator to program the type of activation desired and eventually retrieve data which were formerly stored on the microprocessor memory and is able to activate the trigger device too. The trigger device (6), which inflates the airbag, can be of the same type as used in the car industry.
Due to the very limited current consumption of the intelligent sensing device (in the order of tens of mW), built-in batteries or even solar cells can easily produce this power.
As for reference only, a list of possible electronic component is included:

• sensor: ADXL202AD
• converter AD574A
• CPU MC68HC12
• RAM 6116-6264
• I/O 26LS31 26LS32
• Inflating device: electropyric or compressed air

In conclusion the invention serves to make a system that:

• Can be used with inflatable (or of different technology) devices in order to automatically protect the human body, or can be used "stand-alone" in order to produce alarms (personal safety and or security: it can produce alarms after given variations of trim/ speed/ acceleration/ position that is a fall, a particular position of the body, the exit from a defined area) or store the data relevant to the accident, for later processing.
• It is self contained, that is it does not require any exchange of signals or data with the outside world whilst functioning; moreover it does not require any binding or connection to any whatsoever structure or frame or vehicle.
• Due to the fact that the sensor and all the relevant electronics are miniaturised, it does not produce any harm or trouble to the wearer (it can be miniaturised to a level that it becomes unnoticeable)
• Enable the possibility of monitoring accelerations from e.g. 0.8cm/sec² to 20m/sec² covering all the range of accelerations typical of the human body or its limbs being (or part of it like a leg)
• Has the capability of storing the relevant data of a route (course) in order to reply or analyse it
• Due to the low power consumption small batteries, solar cells or piezoelectric elements can power it.
• If worn by personnel working in an erectioning yard, it can operate the required safety devices, without binding the personnel no ties to structures or frames.