project

I have this project that requires me to modify a car alarm......
So I was thinking that I want to built a anti-tow device, if the car is been tow or the height been change it will trigger the alarm.
I want it to be cheap if possible using infra-red and PIC programming.
Go can anyone pls help me!!!!

just a regular piezeo-electric shock sensor will work. set it to its most sensitive setting.... trust me, it will go off. or get a yaw sensor from a car that has directional stability control. (mazda rx-8) it can detect changes in pitch or roll depending on how you mount it