MotionKit 0.8.1

Maintained by OctoBaig.

You want to add pod 'MotionKit', '~> 0.8' similar to the following to your Podfile:

target 'MyApp' do
  pod 'MotionKit', '~> 0.8'
end

Then run a pod install inside your terminal, or from CocoaPods.app.

Alternatively to give it a test run, run the command:

pod try MotionKit

MotionKit 0.8.1

By
Haroon Baig
PyBaig

MotionKit — The missing iOS wrapper

Now you can grab the data from Accelerometer, Magnetometer, Gyroscope and Device Motion in a magical way, with just a Two or a few lines of code.

A nice and clean wrapper around the CoreMotion Framework written entirely in Swift. The Core Motion framework lets your application receive motion data from device hardware and process that data. The data can be retrieved from Accelerometer, Gyroscope and Magnetometer. You can also get the refined and processed gyroscope and accelerometer data from the deviceMotion datatype itself instead of getting the raw values.

Articles accompanying MotionKit: Link1 — Link2 — Link3

How does it work

You can retrieve all the values either by a trailing closure or by a delegate method. Both the approaches are fully supported.

Note: All the provided methods are Asynchronous and operate in their own Queue so that your app could run smoothly and efficiently.

Initialise

First, initialise the MotionKit instance. Its a Must.

    let motionKit = MotionKit()

Getting Accelerometer Values

You can get the accelerometer values using just a few lines of code.

    motionKit.getAccelerometerValues(interval: 1.0){
        (x, y, z) in
        //Interval is in seconds. And now you have got the x, y and z values here
        ....
      }

Getting Gyroscope Values

Gyroscope values could be retrieved by the following few lines of code.

    motionKit.getGyroValues(interval: 1.0){
        (x, y, z) in
        //Your processing will go here
        ....
      }

Getting Magnetometer Values

Getting Magnetometer values is as easy as grabbing a cookie.

    motionKit.getMagnetometerValues(interval: 1.0){
        (x, y, z) in
        //Do something with the retrieved values
        ....
      }

Installation

Embedded frameworks require a minimum deployment target of iOS 8.

Manual Installation

Just copy the MotionKit.swift file into your Xcode project folder, and you’re ready to go.

CMDeviceMotion - as easy as pie

In case if you want to get the processed values of Accelerometer or Gyroscope, you can access the deviceMotion object directly to get those values, or, you can access the individual values from the standalone methods which work seamlessly with Trailing Closures and Delegates.

The deviceMotion object includes:

Acceleration Data
- userAcceleration
- gravity
Calibrated Magnetic Field
- magneticField
Attitude and Rotation Rate
- attitude
- rotationRate

All of the values can be retrieved either by individual methods or by getting the deviceMotion object itself.

Getting the whole CMDeviceMotion Object

    motionKit.getDeviceMotionObject(interval: 1.0){
        (deviceMotion) -> () in
          var accelerationX = deviceMotion.userAcceleration.x
          var gravityX = deviceMotion.gravity.x
          var rotationX = deviceMotion.rotationRate.x
          var magneticFieldX = deviceMotion.magneticField.x
          var attitideYaw = deviceMotion.attitude.yaw
          ....
        }

Getting refined values of Acceleration

You can get the refined and processed userAccelaration through the Device Motion service by just a few lines of code, either by a Trailing Closure or through Delegation method.

    motionKit.getAccelerationFromDeviceMotion(interval: 1.0){
        (x, y, z) -> () in
          // Grab the x, y and z values
          ....
        }

Getting Gravitational Acceleration

Again, you can access it through the Device Motion service as well.

      motionKit.getGravityAccelerationFromDeviceMotion(interval: 1.0) {
          (x, y, z) -> () in
          // x, y and z values are here
          ....
      }

Getting Magnetic Field around your device

Interesting, Get it in a magical way.

      motionKit.getMagneticFieldFromDeviceMotion(interval: 1.0) {
        (x, y, z, accuracy) -> () in
        // Get the values with accuracy
        ....
        }

Getting the Attitude metrics

      motionKit.getAttitudeFromDeviceMotion(interval: 1.0) {
        (attitude) -> () in
          var roll = attitude.roll
          var pitch = attitude.pitch
          var yaw = attitude.yaw
          var rotationMatrix = attitude.rotationMatrix
          var quaternion = attitude.quaternion
          ....
        }

Getting Rotation Rate of your device

      motionKit.getRotationRateFromDeviceMotion(interval: 1.0) {
        (x, y, z) -> () in
        // There you go, grab the x, y and z values
        ....
        }

Precautions

For performance issues, it is suggested that you should use only one instance of CMMotionManager throughout the app. Make sure to stop receiving updates from the sensors as soon as you get your work done. You can do this in MotionKit like this.

    //Make sure to call the required function when you're done
    motionKit.stopAccelerometerUpdates()
    motionKit.stopGyroUpdates()
    motionKit.stopDeviceMotionUpdates()
    motionKit.stopmagnetometerUpdates()

Delegates

In case if you dont want to use the trailing closures, we’ve got you covered. MotionKit supports the following Delegate methods to retrieve the sensor values.

    optional func retrieveAccelerometerValues (x: Double, y:Double, z:Double, absoluteValue: Double)
    optional func retrieveGyroscopeValues     (x: Double, y:Double, z:Double, absoluteValue: Double)
    optional func retrieveDeviceMotionObject  (deviceMotion: CMDeviceMotion)
    optional func retrieveMagnetometerValues  (x: Double, y:Double, z:Double, absoluteValue: Double)


    optional func getAccelerationValFromDeviceMotion        (x: Double, y:Double, z:Double)
    optional func getGravityAccelerationValFromDeviceMotion (x: Double, y:Double, z:Double)
    optional func getRotationRateFromDeviceMotion           (x: Double, y:Double, z:Double)
    optional func getMagneticFieldFromDeviceMotion          (x: Double, y:Double, z:Double)
    optional func getAttitudeFromDeviceMotion               (attitude: CMAttitude)

To use the above delegate methods, you have to add the MotionKit delegate to your ViewController.

    class ViewController: UIViewController, MotionKitDelegate {
      ...
    }

And in the ViewDidLoad method, you simply have to add this.

    override func viewDidLoad() {
        super.viewDidLoad()
        motionKit.delegate = self
        ......
      }

Having that done, you’d probably want to implement a delegate method like this.

    func retrieveAccelerometerValues (x: Double, y:Double, z:Double, absoluteValue: Double){
      //Do whatever you want with the x, y and z values. The absolute value is calculated through vector mathematics
      ......
    }

   func retrieveGyroscopeValues (x: Double, y:Double, z:Double, absoluteValue: Double){
    //Do whatever you want with the x, y and z values. The absolute value is calculated through vector mathematics
    ......
   }

Getting just a single value at an instant

if you want to get just a single value of any of the available sensors at a given time, you could probably use some of the our handy methods provided in MotionKit.

Accelerometer

    motionKit.getAccelerationAtCurrentInstant {
        (x, y, z) -> () in
        ....
      }

Gravitational Acceleration

    motionKit.getAccelerationAtCurrentInstant {
      (x, y, z) -> () in
      ....
        }

Attitude

    motionKit.getAttitudeAtCurrentInstant {
      (x, y, z) -> () in
      ....
        }

Magnetic Field

    motionKit.getMageticFieldAtCurrentInstant {
      (x, y, z) -> () in
      ....
        }

Gyroscope Values

    motionKit.getGyroValuesAtCurrentInstant {
      (x, y, z) -> () in
      ....
        }

Discussion

You can join our Reddit channel to discuss anything.
You can also open an issue here for any kind of feature set that you want. We would love to hear from you.
Don’t forget to subscribe our Reddit channel, which is /r/MotionKit
Our StackOverflow tag is ‘MotionKit’

Requirements

iOS 7.0+
Xcode 6.1

TODO

[ ] Add More Methods
[ ] Adding Background Functionality

License

This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.