Hello everybody 
I'm a mechanical engineer currently studying sixth semester of my career and I'm having a mechanical vibrations curse.
Our first homework was to assembly a pretty simple system consisting of 2 disks(pulleys), 2 springs and a mass. The problem is that my teacher wants us to use an arduino and an ultrasonic sensor or accelerometer to graph the oscillations of the mass. I already bought an ultrasonic sensor HC-SR04 and an arduino mega, the problem is that I have no idea how to do this.
Somehow I need to use the SR04 to sense vertical displacement of the mass and graph it versus time but I really have no clue how to do this 
can someone help me ? PLEASE
thank you !!
PD the whole objective of this experiment is to determine the damping coefficient of the system