iPhone磁力计传感器

//
//  ViewController.m

#import "ViewController.h"
#import <CoreMotion/CoreMotion.h>

@interface ViewController ()

/** 运动管理 */
@property (nonatomic, strong) CMMotionManager *mgr;

@end

@implementation ViewController

#pragma mark - 懒加载
- (CMMotionManager *)mgr
{
if (_mgr == nil) {
_mgr = [[CMMotionManager alloc] init];
}
return _mgr;
}
- (void)viewDidLoad {
[super viewDidLoad];

// 获取磁力计传感器的值
// 1.判断磁力计是否可用
if (!self.mgr.isMagnetometerAvailable) {
return;
}

// 2.设置采样间隔
self.mgr.magnetometerUpdateInterval = 0.3;

// 3.开始采样
[self.mgr startMagnetometerUpdatesToQueue:[NSOperationQueue mainQueue] withHandler:^(CMMagnetometerData *magnetometerData, NSError *error) {
if (error) return;

CMMagneticField field = magnetometerData.magneticField;
NSLog(@"x:%f y:%f z:%f", field.x, field.y, field.z);
}];
}

@end