Expert iPhone Developer Explains iPhone 4 Accelerometer & Gyroscope

The iPhone wasn’t the first smartphone to include an accelerometer. However, it was the first smartphone to see active widespread development using an accelerometer. The iPhone 4 is the first phone I know of to have a gyroscope though. But, what exactly is an accelerometer and a gyroscope? O’Reilly Answers has a Q&A with an iPhone app development expert that helps explain these two components in non-technical language.
Mobile accelerometers and gyroscopes explained
The Q&A consists of four short sections:
1. What is an accelerometer?
2. What is a gyroscope?
3. What can these tools do on a mobile device?
4. Do these two motion sensors make the iPhone 4 something like the Nintendo Wii’s controllers or Microsoft’s Kinect?