Recommended · for some experience
MPU-6050 Data with a Complementary Filter
Why people recommend it
Pointed to as an example of combining accelerometer and gyro readings from an MPU 6050 to sense orientation in Arduino projects.
Watch for: Gives rotation, not linear movement direction
In their words
From this video [video] it seems like they are using acceleration and gyro to make one rotation direction.
user-2147482637 on arduino.stackexchange.com, Aug 2015. CC BY-SA.