Q. How does my phone know to flip the screen around? And why doesn’t it work sometimes?
A. A sensor called the accelerometer — used inside phones, fitness trackers, smartwatches and other gadgets — measures changes in velocity. The Android or iOS software then uses the accelerometer’s data to tell how you’re holding your phone and orients the screen appropriately so that when you want to switch from browsing the web to watching a wide-screen video, the screen rotates automatically. The accelerometer’s motion-sensing capabilities are also used for things like augmented-reality apps, games and navigation tools that show the rate of speed you (and your phone) are traveling.
If your phone’s screen is not moving when you rotate the device, make sure its orientation lock setting is off. On an Android model, swipe down from the top of the screen to open the Quick Settings box and tap Auto-Rotate. On an iPhone, swipe up from the bottom of the screen to open the Control Center and tap the Orientation Lock icon on the left side of the screen.
If the screen still doesn’t rotate, restart the device. If that doesn’t work, make sure you have the latest system software update. The phone maker’s support site may also have specific troubleshooting advice for your model.
Personal Tech invites questions about computer-based technology to firstname.lastname@example.org. This column will answer questions of general interest, but letters cannot be answered individually.