Velocity

Hi guys

So I have been trying to find a way using drivers, constraints or something of that like, to find the velocity of a given object in an animation. All I want is to put an empty at the velocity vector of an object. This isn’t especially essential to my project but it has been bugging me that there is no way to do it. The closest idea that I had would be to make a driver for the location of the empty that would find the difference between the location of the object it is tracking and the location of that same object in the previous frame. This is giving me a serious headache, please help.