Sensors play a big role in smartphones, improving its usability to a great extent. The integrated sensors have made these devices more than just a communication device. With these sensors, mobile phones act as a thermostat, GPS, air flow detector, and many other devices. The revolution of sensor has transformed a mobile phone into a de facto complete gadget.
Listed below are some useful sensors used in mobile phones:
· Proximity sensor
· Accelerometer sensor
· Ambient light sensor
· Magnetometer sensor
· Image sensor
· Fingerprint sensor
· Moisture sensor
· Tactile sensor
· Temperature sensor
Proximity sensor: A proximity sensor in a mobile phone detects the presence of users’ body and deactivates the display and touch pad of phone when it is brought near the face during a call. What if a screen is active when the user is in a call? Yes, it will send unwanted input and may even cause calls to hang up at the mere touch of your cheek! To avoid such incidents, proximity sensors are being incorporated in touchscreen phones. The sensor even helps save energy by switching off the display.
Accelerometer sensor: This sensor is incorporated to measure the acceleration of the device. In a mobile phone, a 3-axis accelerometer senses the orientation of the mobile phone and changes the screen orientation accordingly. It lets users switch between the portrait and landscape mode smoothly and neatly. Watching videos and gaming on mobile devices are now much more interesting – thanks to accelerometer sensors. In some phones, this sensor also plays a life-saving role, sensing the rate of change of acceleration resulted from a severe jerk from an accident. The sensor helps users make an automatic call for assistance to pre-assigned number, when they face severe and fatal jerk. 3D accelerometer helps in step recognition and is used for sport applications in a phone. It is also used for tap gesture recognition in the user interface for controlling music player and sport application. Nokia 5500 has 3D accelerometer feature.
Ambient light sensor: Ambient light sensor detects light in the surrounding and adjusts the display backlighting accordingly. The backlight is dimmed down, when the surrounding is dark, while the backlight is intensified, when the surrounding light is very bright. The sensor helps users to see the monitor comfortably, at the same time, reduces the power consumption by optimizing display brightness.
Magnetometer sensor: Magnetometer sensor measures strength, orientation, and direction of magnetic field. Phones such as HTC HD2, Nokia N97, Nokia E72, Nokia N8, Samsung Wave S8500, Samsung Galaxy S, HTC Hero, and iPhone 4 come with magnetometer. This sensor orients maps automatically towards North, while navigating and helps find direction in an easy way. This sensor is also known by names such as digital compass or e-compass.
Image sensor: Image sensor converts an optical image into an electric signal. There are two types of image sensors: charge-coupled device (CCD) & metal-oxide-semiconductor active pixel sensor (CMOS APS). CMOS APS is mostly used in a mobile phone camera to sense images. CCD is very good for digital imaging and is mainly used in professional, medical, and scientific applications, where there is need of high quality image. Some of the mobile phones also use CCD sensor for sensing images. Spice Mobiles has launched S-1200 with professional CCD sensor.
Fingerprint sensor: Fingerprint sensor is an advanced feature in mobile phones. It captures digital image of fingerprint pattern. The captured image is digitally processed to create biometric template and is used for matching. Motorola has released some Android phones with fingerprint sensor. This sensor is used for security system on phone.
Moisture sensor: Moisture sensor detects phone’s exposure to moisture. The sensor is embedded in the mobile phone and whenever it comes in contact with moisture, the color of the sensor gets changed. Many phones including iPhones have moisture sensor. You don’t have to be very happy about having a moisture sensor on your handset! The device will stop you from claiming your warranty, when you drop your mobile in water, even if you dry it completely! The warranty of the mobile will be cancelled if the color of the moisture sensor is changed.
Tactile sensor: Tactile sensor is a device that is sensitive to touch, force, and pressure. Capacitive touchscreen phones use touch switch, one of the kinds of tactile sensors. Touch switches detect the presence of finger or hand as well as stylus.
Temperature sensor: iPhone incorporates temperature sensors for device safety. When the temperature sensor indicates that the phone has reached dangerous levels of heat that threatens the internal electronic components of the phone, it shuts down automatically. A warning symbol appears on screen and phone is switched off to get cool down.
Magnetic sensor: Magnetic sensor identifies sensitive element characteristics. In blackberry mobiles, magnetic sensor interacts with the case and deactivates screen and keyboard when the phone is placed in case. It also avoids unwanted input in the device as well as saves the power.
Intelligent sensors have made smartphone a complete device. The business phone and high-end multimedia phones segments are witnessing a trend of incorporation of more and more smart sensors to make the phone more intelligent, increasing its usability to a great extent. The day is not far when your mobile phone will satisfy all your technical needs.