sensor - Measuring the velocity/acceleration of a swinging pendulum

I'm trying to find a good way for measuring the speed/acceleration of a swinging pendulum. I know one way is to use an optical encoder for capturing the rotation positions, but unfortunately there's no room for an optical disc.

I was considering an accelerometer/gyro. Would it be possible? Could I somehow compute the change in pitch? Like with the MPU6050, it can spit out the pitch using its DMP.

Would measuring the change in pitch with an accelerometer/gyro be a good idea?

Answer

The accelerometer will give you exact angle in function as inclinometer, but very slow. The gyro will output a velocity, integrating you get angle, but with offset. A fusion algorithm will give you attitude, accelerometer is correcting the bias of the gyro.