How do I determine the rate of change / velocity of an array of numbers as they occur in real-time?

I need help or a website explaining the best algorithm to calculate the velocity of a stream of numbers as they occur. Basically I have an animation of a spinning wheel and have access to its rotation values in an event as they occur and I want to play different sounds depending on the steepness of the speed at which the animated wheel spins.





Do I need to determine a sample size of the past X number of values and determine their slope? and just keep checking that value as some representation of the wheel's speed? Any algorithms or psuedo-code would be appreciated.





thanks!How do I determine the rate of change / velocity of an array of numbers as they occur in real-time?
鈾?angular position u =w*t; let 螖t is time step;


let max_w is proportional to highest pitch max_f,


i.e. f=r*w, where r is a constant; then


鈾?proc spin;


u2=0;


sound_off;


m: hold(螖t);


pick_up(u1);


if u1=-1 then go_to m1;


w=u1-u0;


f=r*w;


set_pich(f);


sound_on(f);


u0=u1;


go_to m;


m1: sound_off;


retutn;


proc_end;How do I determine the rate of change / velocity of an array of numbers as they occur in real-time?
That's what I thought you would do. Basically the point of a graph at any one time, is the slope or gradient.





There's a website hyperphysics, that explains a lot about phys in general. Usually there are applet's that talk about these things as well.





In my physics course, I can remeber a video showing the rate of change of y, and the rate of change of x





Basically it was just the slope at each point on the line (with a straight tangent line through it), and moving along the curve