Accelerometer and/or Gyroscope for gesture sensing

i want sense 3d motion (gesture). have 3 axis accelerometer. read several articles difference between accelerometer , gyroscope confused if need gyroscope or not orientation , rotation sensing. don't see why accelerometer cannot detect change in orientation.

isn't possible measure them accelerometer alone? because when sensor rotates along 1 axis (say z-axis), there change in y-axis , x-axis output in accelerometer.

is gyroscope necessary or easier if have one?

hi first post. ok in response...velocity change in position time. if sensor sensed velocity, integrate (calculus word) velocity time series (record of velocity time) position. acceleration change in velocity time. have integrate acceleration time series velocity. hence have integrate time series of acceleration twice position. 2-times integration involves setting initial conditions: ex: object stationary @ time = 0 , position of object 0 @ time = 0. last condition easy satisfy since can arbitrarily set x=0 point anything. initial velocity must known @ start of time series. "time series" time record of velocity and/or position of object. thing haven't defined "integrate". term used in calculus indicate summing on time. book on either calculus or numerical analysis explain how numerically integrate. if consult 1 of these books, find out integration results in errors grow time (from t=0). errors can reduced reducing time step used in integration, error principal drawback using accelerometers deduce position. hope brief explanation helps...

Arduino Forum > Using Arduino > Sensors > Accelerometer and/or Gyroscope for gesture sensing

arduino