Very informative, but even with that diagram I don't understand (yet) how the spring types mechanicaly function (at least reliabley), lol.
I do understand there are differnt types of sensors, years ago when I read up on it I read they had impact/crumple sensors (detecting structural "changes") and deacceleration sensors (now you're moving - now you're not). I believe the center one that barely got missed in my incident was an impact/crumple variety sensor, in addition to two other similar ones located around the front lamps/corners. The two other sensors around those same forward positions were of another variety, possibley deaccelration. I was aware after researching, even if the front center-most sensor directly took the impact, that it requires at least one additional trigger, possibley more, including a confirmed triggering from a deacceleration sensor.
But it just adds to the curiosity of why they deployed in Raptor's situation. When researching after my incident I concluded a number of things need to line up for airbags (or any SRS) to deploy, they don't jsut happen randomly.
While there were crumple sensors, I dont believe they are still used in recent model/year. Anyway, the deceleration sensors proved to be a very reliable type of sensor and are now almost exclusively used.
The srping type sensors work a lot like the magnetic type. You have a steel cylinder and, wrapped around it, a spiral shaped spring. One end of the spring is attached to the cylinder, the other to the body of the sensor. Now the sensor is triggered when the deceleration force imparted on the steel cylinder is such that it overcome the tension of the spring and allow it to move forward and touch the contacts. The side airbags sensor use the same arrangement but, obviously, are mounted to be triggered by a lateral impact.
As to the why's the SRS was triggered in Raptor's incident, there are 2 possible explanation
#1 and the most likely by far. The deceleration was brutal enough for the deployement condition to be met and triggered the squib(that's what the explosive in the airbag is called).
#2 there was a multiple malfunction in the SRS(quite unlikely when you know how these systems are monitored by the ECU's but still)
A few others interestings facts about SRS that you may or may not know
-modern SRS usually sport multistage squib for multiple deplyement speed. Usually 2 charges, 1 small and a larger one, giving 3 deployement speed. Slow for the light charge, med for the large charge and fast for both. The selected squib trigger will vary with vehicule speed.
-SRS system often incorporate pyrtechnic seat-belt pre-tensionner. On an impact, a squib in the seat-belt assembly trigger and pull on the belt in an attempt to keep your body from moving forward too far, thus optimizing the function of the front airbags.
-all in all, a modern (circa 2009 and up) can incoporate as much as 16 explosive charge
-You have to be at least 10 inches away from the steering wheel when driving to allow sufficient space for the steering wheel airbag to deploy properly. If you're too close, you risk sever injuries
-Always wear the seat belt. Even if the airbag would be enough to protect you, the seat belt will help keep you inside the car were the vehicule to roll.
-The SRS on some cars will stay activated as long as 15 minutes after the battery has been unplugged. There are condensator built in the SRS ECU that will provide power in case the battery is destroyed by an impact.
These systems are really marvel of engineering and biometric. While earlier systems were rather primitive and sometimes even unsafe, you can be confident that modern SRS systems are reliable and effective.
Drive safely
