I know this has been asked many times. I am integrating acceleration data from MEMS accelerometer to get velocity. I found an app note by freescale - http://cache.freescale.com/files/sensors/doc/app_note/AN3397.pdf It ignores the sampling time to calculate the area. The formula should be sample: Vx= V(x-1)+[N-(N-1) * T]. Right? But the app note it is - Vx = V(x-1)+N+[((N-(N-1))/2] V(x-1) is the previous integration result.