depending on the model is how you'd go about adj the sensitivity. You can add in a motion sensor pretty easily. You don't want it too sensitive, it will get annoying really fast
I believe your talking abost the Shock sensor. What type of Alarm do you have then it could be easier to tell yousome alarms have a little box that has two little knobs on it that you cn use to adjust it, others you have to upgrade to a more/less sensitive one..