В Speedometer.3dr проекте есть скрипт, который и "двигает" стрелку.
Code
//This script adjusts a sprite orientation runtime depending
//on the car's speed. Useful to implement, for example, a
//rotary-dial-based speedomenter
void Main()
{
Quaternion spriteOrientation;
float zero = 110; //gauge position when speed is zero
float range = 6; //gauge range (in degrees) for each meter per second
iQuaternionFromEulerAngles(spriteOrientation,0,0,zero-IN_3*range,"xyz");
iObjectOrientationSet(OBJ_0,spriteOrientation);
}