- PROGRAMMING WITH ARDUINO IDE.

To write the code I used several tutorials found on the web, following links:

- Ultrasonic Ranging HC-SR04.

- How to use more than 3 Ultrasonic HC-SR04 with one FABduino.

- HOW THE CODE WORKS.

To make the code work needed to use the library "< Ultrasonic.h >", so you can get simultaneous operation of more than one sensor at the same time.

What the code does is go reading distances in the 4 sensors simultaneously, always keeping a margin of 50 cm or more, if the reading is less than 50 cm the FABduino sends a signal to the board of the solenoid valve, opening it by 1 second. Thus the compressed air passes through the valve and air fills the airbags.

With the above, it produces the widening of the helmet surface allowing the user to provide more security.