Your phone does more than make calls, take photos, and display notifications. An iPhone can measure pressure, help track elevation, manage hidden storage, protect private apps, and capture detailed images of the Moon. Android phones also offer a useful privacy signal: a tiny blue dot that shows when an app checks your location.
These features are easy to miss because many work behind the scenes. Here is how to use them, understand their limits, and tighten a few settings that can protect your data.
Your iPhone Has a Barometer, But No Built-In Barometer App
Since Apple introduced the iPhone 6 and 6 Plus in 2014, most iPhones have included a built-in barometer. The first-generation iPhone SE is an exception. Apple added the sensor to help determine relative elevation changes, not to provide a standalone weather tool.
Barometric pressure is the force exerted by the air above you. The higher you travel, the less air sits above you, so pressure drops. Your iPhone can translate that change into an approximate elevation reading, which other software can use to track movement or help determine your location.
The sensor cannot tell whether falling pressure means you are climbing a mountain or storm clouds are moving in. Apps need other information, including GPS altitude and local weather station data, to interpret the reading. Apple gives developers access to pressure and altitude information through Core Motion, allowing fitness and outdoor apps to use the sensor in the background.
The Health app uses motion activity, including elevation changes, for step counting and stair climbing. Apple’s Weather app does not use the iPhone’s barometer. It pulls information from external weather data sources, so any pressure reading shown there does not come from the phone’s sensor.
To view the measurement directly, use an app that supports the built-in pressure sensor. Barometer & Altimeter & Thermo says it uses the iPhone barometer and also relies on GPS and weather station information for calibration. It is free, includes commercials, and requires iOS 13 or later as of November 2026. My Altitude uses on-device sensors by default when available, carries a 4.8 overall rating from 27,000 ratings, and offers in-app purchases to remove adverts.
Try checking the pressure before and after walking up a flight of stairs, then return to the same spot and compare weather-related readings. Storms and clearing skies can change pressure too, so do not mistake weather shifts for changes in elevation.
Why System Data Takes So Much Space
Open Settings > General > iPhone Storage and you may find that iOS and System Data occupy a large share of the phone. On 128GB models, those categories can take up nearly half the available storage.
System Data, called Other in older iOS releases, includes files iOS needs but that do not form the core operating system. These files include caches, logs, credentials, extra fonts, keyboards, Siri voices, and downloaded iOS updates that have not been installed. The category can sit at a few gigabytes, expand into the dozens, and then fall back after iOS performs cleanup. Some people report seeing it reach triple digits.
You cannot remove System Data completely, and doing so would hurt performance because apps would need to load content fresh every time. If storage is tight, reboot the iPhone by holding the side button and either volume button, swiping Slide to Power Off, waiting a minute, and holding the side button again. This is not guaranteed, but it can clear some caches and restart background processes.
It is a short-term fix. Delete unused apps and files, including duplicate photos and videos, and download fewer playlists or videos from streaming services when you need more room.
Lock Down Your iPhone and Watch Android’s Blue Dot
Your Lock Screen can expose more than expected. Without a passcode, someone may open Control Center or use Siri, and that could help them put a lost iPhone into airplane mode. Go to Settings > Notifications > Show Previews and choose When Unlocked. Then open Face ID & Passcode or Touch ID, enter your passcode, and review Allow Access When Locked.
Turn off access you do not want, including Control Center, Siri, search, message replies, and home controls. Those features return after authentication. You can also use Safety Check under Settings > Privacy & Security to review permissions, set location access to While Using, turn off Precise Location when an app does not need exact coordinates, and enable App Privacy Report.
Press and hold an app icon to require Face ID or Touch ID every time it opens. You can also hide an app, moving it to a Hidden folder in the App Library that requires authentication. To block tracking requests, open Privacy & Security, choose Tracking, and turn off Allow Apps to Request to Track. Apple Advertising also includes a Personalized Ads setting, which you can disable.
Stolen Device Protection blocks sensitive actions when an iPhone leaves familiar places such as home or work. Even with the passcode, someone may need to wait one hour before accessing passwords or changing Apple Account settings. The feature requires two-factor authentication and Find My, and newer iPhones include it by default.
On Android 17 and newer, a tiny blue dot near the Wi-Fi, battery, and signal icons shows that an app is accessing location data. The indicator covers activity happening now or within the last 10 seconds for foreground apps. Swipe down and tap the indicator to see which app triggered it, or choose See recent access and Location for a fuller history.
Better Moon Photos With Lower Exposure
The Moon often becomes a bright, detail-free circle because the camera tries to balance the dark sky and the Sun-lit surface. Exposure can also fall to 1/30th of a second or lower, making hand movement blur the shot.
A tripod helps, though a book or coffee cup can hold the phone steady. Use the three-second timer from the six-dot camera menu, tap Exposure, and set it to -2EV. Tap and hold the Moon to lock focus and exposure, then drag the sun-icon brightness slider close to its minimum until craters appear.
Recent Pro models offer up to 8x optical-quality zoom and 40x digital zoom, while the iPhone 15 Pro and 16 Pro offer 5x optical and 25x digital zoom. At 25x digital zoom, those models produce an effective 0.48 megapixels from their 12MP cameras. Moontake can set exposure automatically, while Halide Mark III and ProCamera offer manual ISO and shutter-speed controls.
Based on
- Your iPhone has a built-in barometer — Here’s how to use it — engadget.com
- What Is System Data On An iPhone’s Storage, And How Much Is Normal? — engadget.com
- 5 iPhone Security Settings You Should Change To Protect Your Data — engadget.com
- What The Tiny Blue Dot On Your Android Phone Is Telling You — engadget.com
- How To Use Your iPhone To Take The Best Picture Of The Moon — engadget.com
