Learning iPhone Programming

Chapter 10. Using Sensors

Mobile phones aren’t just for making phone calls anymore. The iPhone, like a lot of high-end smartphones these days, comes with a number of sensors: camera, accelerometer, GPS module, and digital compass. We’re entering a period of change: more and more users expect these sensors to be integrated into the “application experience.” If your application can make use of them, it probably should.

Hardware Support

While the iPhone is almost unique among mobile platforms in guaranteeing that your code will run on all of the current devices, there is some variation in available hardware between the various models.

Determining Available Hardware Support

Table 10-1 lists the hardware differences between the devices. Because your app will likely support multiple devices, you’ll need to write code to check which features are supported and adjust your application’s behavior as appropriate.

Table 10-1. Hardware support in various iPhone and iPod touch models

Hardware features	Original iPhone	iPhone 3G	iPhone 3GS	First- generation iPod touch	Second- generation iPod touch	Third- generation iPod touch
Cellular	x	x	x
WiFi	x	x	x	x	x	x
Bluetooth	x	x	x		x	x
Speaker	x	x	x		x	x
Audio-in	x	x	x		x	x
Accelerometer	x	x	x	x	x	x
Magnetometer			x
GPS		x	x
Proximity sensor	x	x	x
Camera	x	x	x
Video capture			x
Vibration	x	x	x

Network availability

We covered Apple’s Reachability code in detail in Apple’s ...