The coolest interface tricks that the iPhone, iPad, and iPod touch can perform — from dimming a phone screen when it’s held to your head to undoing an action by shaking the device and more — are thanks to the sensors built into those devices. Without these sensors, none of these devices would work the way we know and love.

Not every model of iPhone, iPad, or iPod touch has the exact same set of sensors. The functions that the sensors provide are also based on which version of the operating system is installed on the device. That said, the most common sensors used on the iPhone and other devices are:

Although they are generally not explicitly considered sensors, the cameras and microphones built into the iPhone, iPad, and iPod touch function as sensors. So do the devices' Wi-Fi chips and cellular radios. That said, most device manufacturers consider their radios and cameras to be separate from sensors when they list them in device specifications and manuals.

Other types of sensors that are rarely exposed to the user via iOS are thermal sensors. These are used to identify when the device has become too hot to safely operate without risking damaging the hardware.