DevFright

In this tutorial we will look at Device Motion which provides various measurements from the sensors on the iPhone. The data is represented by the CMDeviceMotion class which encapsulates measurements taken by the onboard sensors.

Rather than providing raw values from the accelerometer, gyroscope, or magnetometer, the CMDeviceMotion class provides data that has been processed by “Core Motion’s sensor fusion algorithms”. The data is cleaned up, and has bias removed.

In todays tutorial we’re going to look at how to access CMDeviceMotion and create a simple needle that faces down regardless of the direction you rotate the phone around the Z axis. [Read more…]

The iPhone packs in a number of sensors. We’ve covered the accelerometer, gyroscope, and magnetometer, and will now take a look at the built in barometer which first appeared in the iPhone 6 and 6 plus smartphones several years ago.

The barometer can be used to detect elevation changes by sensing the changes in air pressure as the phone increases or decreases in altitude.

In todays tutorial we’ll take a look at CMAltimeter which is the class we use to access the barometer. [Read more…]

Using the various sensors on your device, Apple is able to predict if you are walking, running, in a vehicle, or stationary. This is all done quietly in the background by way of the motion coprocessor that is found in all iPhones since the 5s.

In this tutorial we will look at how your app can read that information, either live, or historically from the last 7 days. The CMMotionActivityManager has both the live updates using the startActivityUpdates: method, or the historical data with queryActivityStarting: both of which we will use. [Read more…]

The Core Motion framework allows your app access to the sensors on the device. The sensors include the accelerometer, gyroscope, and magnetometer. The CMMotionManager class allows access to each of these to get raw data from them so that your app can detect when the device moves. There are a number of applications for this such as sleep tracking, step counting, to name a few. By using a combination of these sensors, your app can calculate information such as your step count.

Creating a step counter could be quite difficult if you were processing raw data and trying to work out the difference between a step and someone just picking up the phone. Thankfully, Apple does the hard work for you by providing you with the CMPedometer class. This class takes this data and provides you with a step count as well as other information such as cadence etc… To make things even better, Apple also provides 7 days worth of history, thanks to the motion coprocessor (introduced in the iPhone 5s). Even if your app isn’t actively running and tracking step counts, the phone is quietly keeping a log of all step counts and statuses and the CMPedometer is the way we retrieve this data. [Read more…]