int get_vel(void){
   //vel_per has the most recent velocity, measured in # of 100us's
   int i = 0;
   int vel_avg = 0;
   float vel_avg_f = vel_per;

   for(i=0;i<10;i++){
      vel_avg_f += vel_pers[i];         //add each value to the total
   }
   vel_avg_f = vel_avg_f/vel_samples;   //average the array
   vel_avg_f = vel_avg_f * ppr;         //velocity period in ms for 1 rev
   vel_avg_f = 10000 / vel_avg_f;       //vel freq in rev/ms *1000ms / 1s
   vel_avg_f = 60*vel_avg_f;            //(60s / 1min)  this is the rpm
   vel_avg = (int)vel_avg_f;            //convert back to an integer
   return vel_avg;
}