under the car motion sensor?

I recently had my catalytic converter stolen, looks like they cut the exhaust pipe with a sawzall... Anybody have any suggestions for an alarm that would detect someone crawling under the truck? I have seen the "radar" sensors for convertibles that mount on the floor inside the passenger compartment to detect movement inside the vehicle.... would this work mounted upside down on the floorboard underneath the truck and detect motion?  It cost me $2274.00 to get my converter replaced!

you could mount a motion sensor underneath the vehicle, but I'm thinking a dog or cat under your truck would set it off as well.  Wouldn't be so much of a problem unless they triggered the Nuisance Prevention Circuitry which would deactivate that one sensor.  I would mount a second shock sensor close to the catalyic converter, but far enough away that it didn't melt it.  Hard mount the sensor so it's more sensitive. 

i dont see why it would not work.  but in order to use those you need an aftermarket alarm.  and those come equipped with a shock sensor that deffinately would be set of by a saws allyou can do it....

advanced MECP, lol does it really matter....

patience is a virtue