Which sensor allows a smartphone to adjust display brightness based on surrounding light?

The ambient light sensor is crucial for enabling smartphones to automatically adjust display brightness according to the lighting conditions in the environment. When this sensor detects the level of ambient light, it interacts with the device's software to alter the screen brightness, ensuring optimal visibility while also conserving battery life.

For instance, in a brightly lit room or outdoors, the sensor may signal the device to increase the brightness to make the screen readable. Conversely, in darker settings, it can lower the brightness to prevent eye strain and save energy. This functionality enhances user experience by providing appropriate screen visibility without manual adjustments.

The other sensors listed serve different functions: the proximity sensor detects when the phone is close to an object (like a face during a call), the accelerometer measures the device's orientation and motion, and the gyroscope aids in understanding the device's rotation and spatial orientation. None of these contribute to automatic screen brightness adjustment in the way that the ambient light sensor does.