import coremotion

CoreMotion.swift

// 1 import 
import CoreMotion

// 2 create property that can store CMMotionManager
var motionManager: CMMotionManager! 

// 3 initialize it
motionManager = CMMotionManager()

// 4 check accelermoter is available
if motionManager.isAccelerometerAvailable {
  
  // 5 set update interval
  motionManager.accelerometerUpdateInterval = 0.1
  
  // 6 write your logic in the closure 
  motionManager.startAccelerometerUpdates(to: OperationQueue.main) { (data, error) in
      print(data)
  }
}