Get to know Android Sensors

Often when we use Android, we don't realize that Android is a sophisticated smartphone. Various sensors are found on Android smartphones, but what is the use of these sensors? In this article let's share together to get to know sensors on android devices. By knowing him first, it is expected that you can optimize the performance of the sensor more.

In the previous article Droid tips have discussed all the sophistication of Android smartphones, you can read the Android sophistication article . But what will be the question, have you optimized your smartphone? Do you know the usefulness of each sensor embedded in android? In this article we will recognize various sensors on Android so that your device becomes a real smartphone.

Android sensor category
The Android platform supports three broad categories of sensors, namely:
Motion sensor

This sensor measures the strength of acceleration and rotational strength along three axes. This category includes speed, gravity sensors, gyroscopes, and rotation vector sensors.

Environmental sensor

This sensor measures various environmental parameters, such as air temperature, ambient and pressure, lighting, and humidity. This category includes a barometer, photometer and thermometer.

Position sensor 

This sensor measures the physical position of the device. This category includes orientation sensors and magnetometers.

Types of Android sensors

1. Accelerometer

Accelerometer is a transducer that functions to measure acceleration, detect and measure vibration, or to measure acceleration due to earth's gravity.

Implementation and benefits of the accelerometer, one of which is to detect movements such as shakes and tilt. Can be used to measure angles for engineering applications, movement steps for medical applications, to find out the movements when we play games and many more uses of the accelerometer. In its application the accelerometer is usually associated with several other sensors.

Sensor type: Hardware

2. Ambient Temperature

Ambient temperature is a sensor that functions to resemble a thermometer, as a measure of the room temperature around in degrees Celsius / ° C (can also be converted in Fahrenheit / ° F). Not all Android devices have this sensor, only a few devices like the Galaxy S4 have, but if you want to use an ambient temperature sensor and your device does not have the sensor, you must use hardware and your smartphone only as a monitor.

The implementation and benefits of ambient temperature one of them is to find out the temperature of the room we are in so that you can easily adapt, besides that it can also be developed for technical or medical applications.

Sensor type: Hardware

3. Temperature sensor

The temperature sensor is a sensor that functions to measure temperature, its function is almost the same as the ambient temperature and on a device with an ICS version above, this sensor is replaced by an ambient temperature sensor.

The implementation and benefits of temperature sensors are almost the same as ambient temperature.

Sensor type: Hardware

4. Gravity Sensors

Gravitational sensors are sensors that are related to  the gravitational force in m / s2 applied to the device on three physical axes (x, y, z). This measures the component of the gravity vector when the device breaks or moves slowly.

The implementation and benefits of gravity sensors  can be used with game controls using tilt motion can also be used in some other applications. This sensor is usually associated with other sensors such as the accelerometer and others. Some differences between the accelerometer and gravity are the accelerometer gives back the amount of all power applied to your device, while the gravity sensor returns only the influence of gravity. If you want to exclude gravity from acceleration, you can use a high-pass filter or simply reduce the gravity sensor values ​​from the accelerometer sensor values ​​but are not sure which method provides better precision.

Sensor type: Hardware, software

5. Gyroscope

Gryoscope is a sensor assessing device rotation on rad / s around each of the three physical axes (x, y, and z). The gyro sensor detects angular velocity, which is calculated using measurement data taken from a 3-axis to measure or maintain orientation, with the principle of angular momentum determination.

The implementation and benefits of the gyroscope mechanism is a rotating wheel with an internal disk that remains stable. Gyroscope can only be used if there is an accelerometer and can detect movements in all directions. For application, you can use to calculate angles, play games and much more. The movement generated from the gyroscope is smoother than other sensors such as an accelerometer. The gyro sensor is not directly related to gravity because the sensor is a supporter of the accelerometer that has performed calculations by changing gravity directly.

Sensor type: Hardware

6. Light Sensor

The light sensor is a sensor that is useful for measuring the level of ambient light (illumination or measuring the brightness level of light).

The implementation and benefits of light sensors are commonly used to control screen brightness when you are in a place with a different level of light or on a camera application so you don't have to bother adjusting the brightness level. Some developers began to develop this sensor and combine smartphones and vehicles so that they can save vehicle fuel (see picture above). Can also be combined with proximity.

Sensor type: Hardware

7. Linear Acceleration

Linear acceleration is measuring the force of acceleration in m / s2 applied to a device in all three physical axes (x, y, and z), including gravity.

Implementation and benefits of linear acceleration for monitoring acceleration along a single axis and related to other sensors such as an accelerometer for example.

Sensor type: Hardware, Software

8. Magnetic Field

Magnetic fields are sensors for measuring ambient geomagnetic fields in μT. Sometimes referred to as a "magnetometer". This can also be used in determining orientation. The magnetic sensor measures the strength of the magnetic field and fluctuations, and divides the measurements into X, Y, Z and components.

The implementation and benefits of magnetic fields of several compass applications, metal detectors, location predictions and many others as examples of "fun" applications such as ghost sensors which according to rumors are differences in electromagnetic waves for detection.

Sensor type: Hardware

9. Orientation Sensor

The orientation sensor is the sensor of the device coming from the 3-axis acceleration sensor. The following 3 rotation axes show the angle between the gravity vector and the projection of the gravity vector (yaw, pitch, roll).

The implementation and benefits of the orientation sensor you can obtain a tendency and matrix rotation matrix for the device using gravity sensors and geomagnetic field sensors in conjunction with the getRotationMatrix () method  , so you will get the position of your device.

Sensor type: Software

10. Pressure Sensors
A pressure sensor is a sensor used to measure ambient air pressure in hPa or mbar. Often these sensors are called barometric sensors.

Implementation and benefits of pressure sensors  you can use to measure air pressure, for me this sensor is very important to use for those of you who work as a SAR team or nature lovers, this sensor can be used to calculate the height of your position (altimeter) and many more uses. Besides that there are many other developments such as for example to calculate the pressure on your trial project or can also calculate the wind pressure on the tire (bike tire pressure system). But not all Android devices have these sensors, only a few have as an example: Xperia Active, Nexus, Galaxy S3, Galaxy S4 and some others.

Sensor type: Hardware

11. Proximity

Proxymity is a sensor used to detect the presence of an object without physical contact. 

The implementation and benefits of proximity sensors, one of which is to turn off the screen automatically when we call, it aims to save battery, in addition to these functions, you can optimize the sensor to play music, screen off or much more that you can optimize especially when you are driving or cooking so that you are more focused and can still operate the device without having to make physical contact with the device.

Sensor type: Hardware

12. Humidity sensor

The humidity sensor is a sensor that is useful for measuring relative ambient humidity in percent (%).

The implementation and benefits of  ordinary humidity sensors are related to the temperature sensor to calculate the humidity level where you are. This sensor is also rarely found on android devices, only a few of which use this sensor for example galaxy s4. If your device has a humidity sensor, you can optimize it to calculate the humidity of your home so that your home is healthier or can be used to calculate humidity and soil that is suitable for plants if you are a farmer, regulate the humidity of your pet cage or much more.

Sensor type: Hardware

13. Rotation Vector

Rotation vectors are sensors for measuring device orientation by providing three elements of vector rotation devices.

The implementation and benefits of rotation vector are  almost the same as a motion sensor, but this sensor refers more to the rotation of your device.

Sensor type: Hardware, Software

14. Some other additional sensors such as finger print (for example on motorola atrix), development sensors from other hardware such as facelock, smart stay, sound sensor) and several others.

Android version that can use sensors

Sensor	Android 4.0  (API Level 14)	Android 2.3  (API Level 9)	Android 2.2  (API Level 8)	Android 1.5  (API Level 3)
TYPE_ACCELEROMETER	Yes	Yes	Yes	Yes
TYPE_AMBIENT_TEMPERATURE	Yes	n / a	n / a	n / a
TYPE_GRAVITY	Yes	Yes	n / a	n / a
TYPE_GYROSCOPE	Yes	Yes	n / a 1	n / a 1
TYPE_LIGHT	Yes	Yes	Yes	Yes
TYPE_LINEAR_ACCELERATION	Yes	Yes	n / a	n / a
TYPE_MAGNETIC_FIELD	Yes	Yes	Yes	Yes
TYPE_ORIENTATION	Yes 2	Yes 2	Yes 2	Yes
TYPE_PRESSURE	Yes	Yes	n / a 1	n / a 1
TYPE_PROXIMITY	Yes	Yes	Yes	Yes
TYPE_RELATIVE_HUMIDITY	Yes	n / a	n / a	n / a
TYPE_ROTATION_VECTOR	Yes	Yes	n / a	n / a
TYPE_TEMPERATURE	Yes 2	Yes	Yes	Yes

Information:
1. The sensor type was added on Android 1.5 (API Level 3), but it's not available for use until Android 2.3 (API Level 9).

2. This sensor is available, but is outdated.

You can read more information on the sensor overview article  .

Diagnosis of android sensors
Some applications you can use to find out how many sensors are on your device, you can try downloading the application.

Solution when the sensor on your device is not working
1. Look for references to sensors available on your device and if you believe the sensor is there, use an application to diagnose your sensor.
2. Make sure your firmware / ROM does not have bugs in sensor performance, read the review first before you flash ROM so you know what sensors will not work when you get a bug.
3. Make sure the application you are using does not crash and supports the sensor features of your device
4. If you believe the three steps above, try contacting your service center or trust engineer to check or replace the hardware / chip sensor and software related to the sensor performance on your device.

I wrote this article based on references from several articles on the internet, experiences from several senior colleagues and personal experience. CMIIW. If you have suggestions or feedback please leave it via the comments column.