Jakub Hałun – Apps – Sensor Tester: Description

Sensor Tester: Description

Sensor Tester

Android application for Android 7.0 and later, free and ad-supported

Sensor Tester shows live readings from the sensors and the battery of an Android device on a single scrolling screen: the battery and seventeen types of sensors, from the accelerometer and the gyroscope to the uncalibrated sensors, the rotation vectors and the true-north heading. For each type the app reads the device's default sensor, and a type the device does not have is listed as not available. Readings are updated while the app is open; nothing is recorded in the background.

Version 2.0.0 is a major refresh of an app first published in 2014: six new sensor types, units on every reading, steadier numbers on the main screen, battery current and charge counters, the accuracy and status of each sensor, better accessibility and a refreshed look. The changelog lists everything that changed.

Screenshots

Sensor Tester main screen with the hint to touch and hold a sensor for details, and live readings of the battery, the accelerometer and the uncalibrated accelerometer with its estimated bias, all with units

End of the main screen with the rotation vector, the game rotation vector and the geomagnetic rotation vector, with the heading accuracy in radians, and the heading sensor shown as not available

Details of the uncalibrated accelerometer: the reading and the estimated bias at full precision, the sensor's name, vendor and version, maximum range, resolution, minimum delay, declared current and reported accuracy

Battery details: level, temperature and voltage, technology, charging source, health and status, followed by the current, average current, charge counter and energy counter

Preferences with the option to show only available devices and a checkbox for every sensor type

Sensors

The main screen lists the battery and every supported sensor type with its current reading, in the units Android defines for it. Each value is rounded to the resolution the sensor declares, so the numbers stay readable while they change. Every row also shows its state: waiting for the first value, activation failed, or permission needed. A sensor type your device does not have is shown as not available, and Preferences can hide it.

Touch and hold a sensor to open its details screen. It shows the reading at full precision together with the sensor's name, vendor and version, maximum range, resolution, minimum delay between events, the current the sensor declares and the accuracy it reports. Battery details add the technology, the charging source (AC, USB, wireless or dock), health and status, and, where the device reports them, the current, average current, charge counter and energy counter. Copy to Clipboard in the menu copies the readings as they are shown.

Sensor	What it shows
Battery	Charge level (%), temperature (°C) and voltage (V), from the system battery status.
Accelerometer	Acceleration along the X, Y and Z axes, including gravity (m/s²).
Accelerometer (Uncalibrated)	Acceleration without bias compensation, with the estimated bias (m/s²). Android 8.0 and later.
Magnetometer	Ambient magnetic field along the X, Y and Z axes (µT).
Magnetometer (Uncalibrated)	Magnetic field without hard-iron calibration, with the estimated bias (µT).
Gyroscope	Rate of rotation around the X, Y and Z axes (rad/s).
Gyroscope (Uncalibrated)	Rate of rotation without drift compensation, with the estimated bias (rad/s).
Light	Ambient illuminance (lx).
Gravity	Direction and strength of gravity along the X, Y and Z axes (m/s²).
Temperature	Ambient air temperature (°C).
Pressure	Atmospheric pressure (hPa).
Humidity	Relative humidity of the air (%).
Proximity	Distance of an object from the screen (cm), labeled near or far.
Linear Acceleration	Acceleration along the X, Y and Z axes with gravity removed (m/s²).
Rotation Vector	Device orientation as the components of a rotation vector, with the heading accuracy (rad) when the sensor reports it.
Game Rotation Vector	Device orientation without the magnetometer, so its heading has no north reference.
Geomagnetic Rotation Vector	Device orientation from the accelerometer and the magnetometer, without the gyroscope, with the heading accuracy (rad) when reported.
Heading	Direction the device points, in degrees from true north, with its accuracy. Android 13 and later.

Some of these are not separate pieces of hardware: the device computes gravity, linear acceleration, the rotation vectors and the heading from other sensors, and each uncalibrated sensor is the same hardware as its calibrated counterpart. Most phones have no temperature, humidity or heading sensor.

Preferences

Preferences in the menu choose what the main screen shows:

Show only available devices hides the sensor types your device does not have.
A checkbox for every entry, the battery and each of the seventeen sensor types, includes it in the main screen or leaves it out.
Reset Preferences in the menu restores the defaults: every entry selected and the filter off.

Accessibility

Text follows the system font size, and the checkboxes in Preferences are large touch targets. TalkBack, Switch Access and Voice Access offer a View details action on every available sensor, in place of the touch and hold gesture.

Advertisements and privacy choices

Sensor Tester is free and supported by advertising: a single small banner ad (Google AdMob) at the bottom of the main screen and of the details screens. The ads are deliberately unobtrusive:

One banner, below the readings: the ad has its own strip under the list and never covers a reading. The strip takes its full height before an ad arrives, so an ad never appears under your finger.
No ad, no empty space: when no ad is available, for example without an internet connection or before you have answered the consent form, the strip disappears completely. All sensor readings work offline; only the ad, the consent form and the usage statistics use the network.
Consent first: where the law requires it, in the European Economic Area, the United Kingdom and Switzerland, the app shows Google’s consent form before any ad is requested or any usage statistics are sent. You can change your choice at any time with Privacy options in the menu, which is shown whenever the consent form applies to you.
Usage statistics: the app uses Google Analytics for Firebase to see how it is used, such as sessions and the screens viewed. It never sends sensor readings.

Sensor readings are only shown on your device: the app does not record them, does not send them anywhere and stops reading the sensors when you leave it. The privacy policy describes what the Google services collect and how to change your choices.

Permissions

Sensor Tester never asks for a permission while you use it: reading the sensors and the battery needs none. It declares only permissions that Android grants at installation:

Internet access and network state: used only for the banner ad, the consent form and the usage statistics.
Advertising ID: lets the ad and statistics services use the advertising ID, subject to your consent and your device settings.
Permissions added by the Google libraries: for Android’s Privacy Sandbox ad interfaces where the device offers them, for the libraries’ background work, and for Google Play’s install referrer.