iOS Gyroscope API

Question

I am learning to write an app using the gyroscope sensor in iOS. Are there classes for dealing with the gyroscope similar to UIAcceleration/UIAccelerometer/UIAccelerometerDelegate for the accelerometer?

Answer 1

First import CoreMotion framework

#import <CoreMotion/CoreMotion.h>

    self.motionManager = [[CMMotionManager alloc] init];


    //Gyroscope
    if([self.motionManager isGyroAvailable])
    {
        /* Start the gyroscope if it is not active already */ 
        if([self.motionManager isGyroActive] == NO)
        {
            /* Update us 2 times a second */
            [self.motionManager setGyroUpdateInterval:1.0f / 2.0f];

            /* Add on a handler block object */

            /* Receive the gyroscope data on this block */
            [self.motionManager startGyroUpdatesToQueue:[NSOperationQueue mainQueue]
             withHandler:^(CMGyroData *gyroData, NSError *error)
            {
                NSString *x = [[NSString alloc] initWithFormat:@"%.02f",gyroData.rotationRate.x];
                self.gyro_xaxis.text = x;

                NSString *y = [[NSString alloc] initWithFormat:@"%.02f",gyroData.rotationRate.y];
                self.gyro_yaxis.text = y;

                NSString *z = [[NSString alloc] initWithFormat:@"%.02f",gyroData.rotationRate.z];
                self.gyro_zaxis.text = z;
            }];
        }
    }
    else
    {
        NSLog(@"Gyroscope not Available!");
    }

As the code says, first I create an instance of motion manager. Then I see if the device supports Gyroscope. If not die gracefully, else set gyroscope update interval & then register to get updates from gyroscope. With these updates you need to define your custom logic of what you want to do with the values. That's it you are good to go...

Answer 2

For gyroscope data, you'll need to use CoreMotion. Get started by reading the relevant section of the Event Handling Guide for iOS. You'll need to work with two classes: CMGyroData which encapsulates gyroscope event data, and CMMotionManager which is used to register for gyroscope events.

More information can be found in this question's selected answer: Apple gyroscope sample code