iOS 7-检测物理敲击/硬拍击（非抖动）

我正试图通过加速计检测爆震（即在手机背面）。我只能找到这段代码，但大部分代码在iOS 7中已被弃用，我不知道如何“重新编码”

以下是我使用的代码：

#define kUpdateFrequency    100.0
#define kFilteringFactor    0.1
float accelZ;
int spikeZCount = 0; 

[[UIAccelerometer sharedAccelerometer] setUpdateInterval:1.0 / kUpdateFrequency];
[[UIAccelerometer sharedAccelerometer] setDelegate:self];

- (void) accelerometer: (UIAccelerometer *) accelerometer didAccelerate: (UIAcceleration *) acceleration {
accelZ = acceleration.z - ( (acceleration.z * kFilteringFactor) + (accelZ * (1.0 - kFilteringFactor)) );

    if (accelZ > 0.0f) {
        if (spikeZCount > 9) {
            //  NSLog(@"SPIKE!");
            [[UIAccelerometer sharedAccelerometer] setDelegate:nil];

            [self isBumped];
        }
        else {
            spikeZCount++;
            //  NSLog(@"spikeZCount %i",spikeZCount);
        }
    }
    else {
        // NSLog(@"spikeZCount Reset");
        spikeZCount = 0;
    }
}

谢谢