rotation fun.....

ok..so i have a question..

how can i make it to where i use a sensor.. (1 time.. not repeated)
and make it 3m in front of the avatar... and at proper rotation?

this is what i have so far

listen(integer channel,string name,key ids,string str)
{
if (llGetOwnerKey(ids) == llGetOwner()){ llSensor("",(key)str,AGENT,96,2*PI);}//sensors only work up to 96meters, but llSetPos can only move up to 10 meters
}
sensor(integer num)
{
target = num;
llSetPos(llDetectedPos(0)+ <3,0,0>*llDetectedRot(0));//3 meters in front of the avatar's local rotation, it was global previously
llGetCameraRot();
llSetRot(llDetectedRot(0));
}
}