在iOS中查找速度和加速度

Question

請在iPhone中使用Accelerometer查找加速度和速度（速度）的過程。

使用下面的代碼來測量加速度和速度。但沒有得到正確的速度值。

CMMotionManager *motionManager; 
motionManager = [[CMMotionManager alloc] init]; 
motionManager.accelerometerUpdateInterval = 1.0/10.0; 
[motionManager startDeviceMotionUpdates]; 
CMMotionManager *mManager = [[CMMotionManager alloc] init]; 


    [mManager setAccelerometerUpdateInterval:0.1];// Update at 10Hz 
    [mManager startAccelerometerUpdatesToQueue:[NSOperationQueue mainQueue] withHandler:^(CMAccelerometerData *accelerometerData, NSError *error) { 

     motionManager = mManager; 

     gravX = (accelerometerData.acceleration.x * kFilteringFactor) + (gravX * (1.0 - kFilteringFactor)); 
     gravY = (accelerometerData.acceleration.y * kFilteringFactor) + (gravY * (1.0 - kFilteringFactor)); 
     gravZ = (accelerometerData.acceleration.z * kFilteringFactor) + (gravZ * (1.0 - kFilteringFactor)); 

     UIAccelerationValue accelX = accelerometerData.acceleration.x - ((accelerometerData.acceleration.x * kFilteringFactor) + (gravX * (1.0 - kFilteringFactor))); 

     UIAccelerationValue accelY = accelerometerData.acceleration.y - ((accelerometerData.acceleration.y * kFilteringFactor) + (gravY * (1.0 - kFilteringFactor))); 
     UIAccelerationValue accelZ = accelerometerData.acceleration.z - ((accelerometerData.acceleration.z * kFilteringFactor) + (gravZ * (1.0 - kFilteringFactor))); 

     accelX *= 9.81f; 
     accelY *= 9.81f; 
     accelZ *= 9.81f; 


     UIAccelerationValue vector = sqrt(pow(accelX,2)+pow(accelY,2)+pow(accelZ, 2)); 
     UIAccelerationValue acce = vector - prevVelocity; 
     UIAccelerationValue velocity = (((acce - prevAcce)/2) * (1/kAccelerometerFrequency)) + prevVelocity; 
     NSLog(@"Prev Velocity: %f",prevVelocity); 
     NSLog(@"Velocity :%f",velocity); 

     prevAcce = acce; 
     prevVelocity = velocity; 


     self.accelerationLbl.text = [NSString stringWithFormat:@"%.2f",vector]; 
     self.velocityLbl.text = [NSString stringWithFormat:@"%.2f",velocity]; 



    }]; 

Answer 1

試試這個代碼：

在你ViewDidLoad方法

[self setAccelerometerEnabled:NO]; 
[[UIAccelerometer sharedAccelerometer] setUpdateInterval:1/60]; // this is for your Accelerometer speed 

Accelerometer委託方法：

- (void) accelerometer:(UIAccelerometer *)accelerometer didAccelerate:(UIAcceleration *)acceleration 
{  
    CGPoint playerPos = [imageview position]; 
    playerPos.x += kXFilterFactor * acceleration.y; 
    playerPos.y += kYFilterFactor * -acceleration.x; 

    if (playerPos.x < 10) 
    { 
     playerPos.x = 10; 
    } else if (playerPos.x > self.view.frame.size.width - 10) 
    { 
     playerPos.x = self.view.frame.size.width - 10; 
    } 

    if (playerPos.y< 10) 
    { 
     playerPos.y = 10; 
    } else if (playerPos.y > self.view.frame.size.height - 10) 
    { 
     playerPos.y = self.view.frame.size.height - 10; 
    } 
    [imageview setPosition:playerPos]; 
}