Alasdair Allan 
Basic Sensors in iOS [PDF ebook] 
Programming the Accelerometer, Gyroscope, and More

What really sets the i Phone apart from laptops and PCs is its use of onboard sensors, including those that are location-enabled. This concise book takes experienced i Phone and Mac developers on a detailed tour of i Phone and i Pad hardware by explaining how these sensors work, and what they’re capable of doing.With this book, you’ll build sample applications for each sensor, and learn hands-on how to take advantage of the data each sensor produces. You’ll gain valuable experience that you can immediately put to work inside your own i OS applications for the i Phone, i Pod touch, and i Pad. This book helps you focus on:Camera: learn how to take pictures and video, create video thumbnails, customize video, and save media to the photo album Audio: use the media picker controller and access the i Pod music library in your own application, and enable your app to record and play sampled audio Accelerometer: write an application that uses this sensor to determine device orientation Magnetometer: learn how this sensor verifies compass headings Core Motion: use this framework to receive motion data from both the accelerometer and the vibrational gyroscope This short book is part of a collection that will, along with new material, be compiled into a larger book, i OS Sensor Programming. The other books in this collection are Augmented Reality in i OS, Geolocation in i OS, and i OS Sensor Apps with Arduino.