A shock sensor detects an impact to the body of the vehicle, such as someone hitting a door panel. It helps protect the body of your car plus will act as a warning to a potential thief that an alarm is fitted (thieves will often whack the vehicle to test if it has an alarm).
There are three types of AVS shock sensors:
Single stage shock sensor
The AVS single zone, or single stage shock sensor, triggers a full alarm if an impact is detected to the vehicle. The AVS A4 and AVS A5 car alarms include this sensor as standard (from May 2016). It can be added as an optional upgrade to any 12 volt AVS car alarm.
Dual stage shock sensor
The AVS dual zone, or dual stage shock sensor has two stages. It will give warning chirps if a light impact is detected to the body of the car and then triggers the full alarm if a heavy impact is detected.
Intelligent dual stage shock sensor
As well as the dual stage functionality above, this sensor can distinguish between environmental shocks such as trucks or aircraft and a thief attempting to break in as well as auto adjust its sensitivity for the environment on arming to help prevent false triggers. The AVS S4 and AVS S5 car alarms include this sensor as standard. It is only available on AVS S-Series car alarms.