Smartphones have come along way. Today, almost all smartphones are equal, except a few who claim more equality for the simple reason that they are more expensive. By every day functionality, flagships like Samsung Galaxy S8, the yet to be revealed iPhone 8, LG G6, HTC U11, etc, are no more different from low budget smartphones from Tecno, Infinix, Innjoo, Itel, and Cubot. This is because all these phones come with common powerful smartphone sensors that level out the ground in the ongoing smartphone wars.
It is important to point out that other than price, the flagships may have a few more sensors e.g. fingerprint sensors (already finding way in the low budget smartphones), NFC, and heartbeat monitors (whose functionality can be achieved without a specific heartbeat sensor). The flagships may also have more powerful processors, larger RAM, better screens in terms of resolution and display tech, premium metallic or glass casing, and body protection e.g. against accidental fall in water. The flagships, just like any other low budget smartphone, have crucial sensors that make them what they are, smartphones. These mandatory smartphone sensors that every smartphone must have include GPS, Accelerometer, Gyroscope, Compass, Proximity and Ambient Light sensor.
Let us examine these smartphone sensors and why you must ensure your smartphone has all of them.
Technically, GPS refers to the United States global position satellites that provide geolocation and time information to anyone who has a GPS receiver. It is this GPS receiver that we call the GPS sensor. For a GPS receiver to know its location, it must be connected to at least 3 satellites at any given moment. If the location includes altitude information, then the receiver must be connected to at least 4 satellites.
However, what we typically refer to as GPS in smartphones is not limited to the GPS satellites system. Location triangulation using cell towers and WiFi routers is also used by smartphones, and together with the GPS satellites the smartphone can calculate the device’s location to less than 10 meters radius. GPS alone can provide location information to this 10 meters radius but generally the GPS would drain a lot of power and only works outdoors.
GPS sensor is one of the most important smartphone sensors, as many Apps including Maps, Social Media Apps, and Dating Apps require location information in order to serve you better. There are features in Apps such as Tinder and WeChat that may not work if you do not have a phone with proper GPS sensor. If for example you have been experiencing trouble when trying to get connected to people near you on Tinder or WeChat, then the issue you may be having is a poor GPS sensor or bad location algorithm in your smartphone.
Accelerometer measures acceleration due to gravity – also called proper g force or free fall. In smartphones, we interact with this sensor every time we turn that Portrait/Auto icon on and off. On portrait, we are telling the smartphone to lock the phone’s orientation on the portrait however the orientations of the smartphone may be. On Auto, we tell the smartphone to activate the accelerometer so that the sensor can re-orient the screen to landscape or portrait to align with the orientation of the smartphone.
The accelerometer in smartphones is generally made up of a circuit having ‘Seismic mass’ (made up of Silicon) that changes position as the smartphone’s orientation changes. According to Techulator, a smartphone with an accelerometer “is nothing but a circuit based on MEMS(Micro Electro Mechanical System), that senses or measures the forces of acceleration that may be caused due to gravity of movement or tilting action”.
In summary, a smartphone’s accelerometer orients’s your screen, although the sensor by itself has higher applications elsewhere. In smartphones, the accelerometer also helps to receive shake based commands. For example in certain Apps, you may shake your device in order to refresh the App, or even get connected to someone who is also shaking at his/her device at the same instant in time e.g. as done in WeChat.
Accelerometer works well when measuring orientation on non-moving objects. However, introduce movement (velocity) to the smartphone and the sensor loses its appeal. How then can you determine orientation of a device in places such as inside high velocity vehicles or spacecrafts? Gyroscope comes in. By and large Accelerometer and Gyroscope perform the same basic function of determining a device’s orientation, but through totally different scientific principles as explained by LiveScience below:
The main difference between [accelerometer and gyroscope] is simple: one can sense rotation, whereas the other cannot. In a way, the accelerometer can gauge the orientation of a stationary item with relation to Earth’s surface. When accelerating in a particular direction, the accelerometer is unable to distinguish between that and the acceleration provided through Earth’s gravitational pull. If you were to consider this handicap when used in an aircraft, the accelerometer quickly loses much of its appeal.
The gyroscope maintains its level of effectiveness by being able to measure the rate of rotation around a particular axis. When gauging the rate of rotation around the roll axis of an aircraft, it identifies an actual value until the object stabilizes out. Using the key principles of angular momentum, the gyroscope helps indicate orientation. In comparison, the accelerometer measures linear acceleration based on vibration.
Generally, Accelerometer and Gyroscope should together be used by Apps to determine the direction of the north pole. However, smartphones also come with magnetometer built to measure the earth’s magnetic field. The magnetometer together with accelerometer and gyroscope will work together not only to always pin point the north but also do so whatever the tilt of the smartphone or its speed may be. The compass sensor is important in maps applications.
Proximity sensor played a great role in the Samsung Galaxy S3. Simply after selecting a contact, you could place the S3 on your ear and the phone could automatically place the call. Wider application of the Proximity sensor is with smartphone’s ability to turn the screen off whenever making calls. If the screens were not turned off during calls, then the face could still touch various parts of the screen and perform unintended actions, which could include accidentally terminating an ongoing phone conversation.
Smartphone sensors for proximity detection are generally of two types, the InfraRed based sensors and the Capacitive based sensors. The IR proximity sensors are probably what your smartphone has today, and it works by sending IR beam and measures the changes of return signal. On the other hand, capacitive proximity sensors generate an electrostatic field and reacts to changes in capacitance caused when a target enters the electrostatic field.
IR proximity sensors have challenges in power consumption, dirt interference with the IR sensor, blind spots, high cost and unreliable performance over temperature, hair, and skin color variations. These challenges are being addressed with the adoption of the capacitive proximity sensors.
Ambient Light Sensor
If your smartphone cannot automatically control screen’s brightness it’s mostly because it lacks the Ambient Light sensor. Being able to automatically control your screen’s brightness is one of the best ways to save the battery juice. Good ambient light sensors work well no matter the light source – be it direct sunlight, fluorescent or incandescent lamps. As has been noted by EE Times, the ambient light sensors in today’s smartphones match or virtually match the requirements of the human eye which is a big deal when it comes to reducing eye strain.
Those are the very basic smartphone sensors that you need to always ensure are present in your smartphone. Basically therefore, your smartphone should be able to give your accurate location information even when you are indoors, accurately orient your screen either according to your own orientation or according to how you have oriented your device, be able to provide you with compass directions no matter your location or your phone’s orientation, and save your battery by turning your screen off through the use of both proximity and ambient light sensors.
Before taking that smartphone home, always ensure to test those basic smartphone functionalities. Also try to ensure that they have the best smartphone sensors.