As we all know, mobile phones have come a long way from being a device for making calls and sending text messages to becoming smartphones. One of the important factors that make these phones ‘SMART’ is the way these phones leverage data received by the various sensors built in the phone itself. Let us see a few of these sensors and technologies.
1. GPS – The GPS (Global Positioning System) is a space based global navigation satellite system that provides location and time information in any weather, anywhere on Earth. This is one of the oldest technologies used, work on which started way back in 1973. It was realized by the U.S. Department of Defense, and currently there are 24 satellites that make up the GPS space segment are orbiting the earth about 12,000 miles above us.
This isn’t a sensor built in the device, there’s just a GPS receiver in the device. Nevertheless, with the mobile phones becoming smart, your mobile phone can itself become a GPS device, unlike the old days where one had to have a separate GPS device.
Usage – Location based apps are the best apps to leverage the GPS.
eg. Google maps, places, Where To Eat, GPS Essentials, GPS Test, etc.
2. Proximity Sensor - A proximity sensor is a sensor able to detect the presence of nearby objects without any physical contact. It is exactly what it name suggests. It measures the proximity of objects near it. i.e. how near or far an object is from the sensor.
A proximity sensor often emits an electromagnetic or electrostatic field, or a beam of IR radiation, and looks for changes in the field or return signal. The object being sensed is often referred to as the proximity sensor's target. Different proximity sensor targets demand different sensors. For example, a capacitive or photoelectric sensor might be suitable for a plastic target; an inductive proximity sensor requires a metal target. The maximum distance that this sensor can detect is defined "nominal range".
A proximity sensor adjusted to a very short range is often used as a touch switch. A proximity sensor is divided in two halves and if the two halves move away from each other, then a signal is activated.
Usage – Earlier used in rear bumpers of cars to assist while parking. Now used in many smartphones to detect how far the phone is from the user. Eg. During a call, when the user holds the phone near his/ her ear, the proximity sensor deactivates the screen. On taking the phone away from the ear, the screen is re-activated.
3. Ambient light sensor - Ambient light sensors are included in many laptops and cell phones to sense the environment lighting conditions, allowing for adjustment of the screen's backlight to comfortable levels
for the viewer. The range of "comfortable levels" is dependent on the room's light.
Usage - Understandably, a screen's brightness needs to increase as the ambient light increases. What is less obvious is the need to decrease the brightness in lower light conditions-for comfortable viewing and to save battery life.
Other than this, the ambient light sensor is also used for improving the quality of photos that are clicked from the phone camera in a dimly lighted area.
4. Accelerometer - An accelerometer is an electromechanical device that will measure acceleration forces. These forces may be static, like the constant force of gravity pulling at your feet, or they could be dynamic - caused by moving or vibrating the accelerometer. By measuring the amount of static acceleration due to gravity, you can find out the angle the device is tilted at with respect to the earth. By sensing the amount of dynamic acceleration, you can analyze the way the device is moving. At first, measuring tilt and acceleration doesn't seem all that exciting. However, engineers have come up with many ways to make really useful products using them.
An accelerometer can help your project understand its surroundings better. Is it driving uphill? Is it going to fall over when it takes another step? Is it flying horizontally or is it dive bombing your professor? A good programmer can write code to answer all of these questions using the data provided by an accelerometer
High g accelerometers are the industry standard way of detecting car crashes and deploying airbags at just the right time.
A number of smartphones use accelerometers to align the screen depending on the direction the device is held, for example switching between portrait and landscape modes.
It is also useful for auto image rotation, motion-sensitive games, and to correct shake when taking photographs.
Usage – Many apps like Shake Them All, Labyrinth Lite leverage the accelerometer.
You can find a nice tutorial to start using the accelerometer in your apps here
5. Gyroscope - An accelerometer measures acceleration. A 3-axis accelerometer will tell you the orientation of a stationary platform relative to earth's surface, once that platform starts moving, however, things get more complicated. If the platform is in free-fall, it will show zero acceleration. If it is accelerating in a particular direction, that acceleration will simply be added to whatever acceleration is being provided by gravity, and you will not be able to distinguish
Here’s where the gyroscope comes in.
A gyro measures rate of rotation around a particular axis. If a gyro is used to measure the rate of rotation around the aircraft roll axis, it will measure a non-zero value as long as the aircraft is rolling, but measure zero if the roll stops.
So, in a nutshell: Accelerometers are right in the long term but wrong (noisy) in the short term. Gyros are right in the short term but wrong (drifiting) in the long term. You need both--each to calibrate the other--to be right all the time.
I found a good video tutorial that compares the two sensors. The video is by InvenSense, who made the Wii MotionPlus, using Gyroscopes and Accelerometers to capture precise human hand movement.
Usage - Firing Range is one of the best apps that makes use of both the sensors. Do have a look at it.
Asphalt 5 is another great example of how the motion sensors can be leveraged in applications.
Not to mention the very famous ANGRY BIRDS…
6. Magnetometer –
is a measuring instrument used to measure the strength and/or direction of the magnetic field, produced either in the laboratory or existing in nature.
Usage - This one allows the phone to be used as a precise compass. Eg. Super compass and 3D compass
These are but a few uses of the sensors. A lot of research is being carried out to use these sensors in the health care industry, apart from games and apps. There’s a lot of scope to leverage the data generated form these sensors. It’s up to you what you make of these vast resources of data available literally at your fingertips. :-)
1. GPS – The GPS (Global Positioning System) is a space based global navigation satellite system that provides location and time information in any weather, anywhere on Earth. This is one of the oldest technologies used, work on which started way back in 1973. It was realized by the U.S. Department of Defense, and currently there are 24 satellites that make up the GPS space segment are orbiting the earth about 12,000 miles above us.
This isn’t a sensor built in the device, there’s just a GPS receiver in the device. Nevertheless, with the mobile phones becoming smart, your mobile phone can itself become a GPS device, unlike the old days where one had to have a separate GPS device.
Usage – Location based apps are the best apps to leverage the GPS.
eg. Google maps, places, Where To Eat, GPS Essentials, GPS Test, etc.
2. Proximity Sensor - A proximity sensor is a sensor able to detect the presence of nearby objects without any physical contact. It is exactly what it name suggests. It measures the proximity of objects near it. i.e. how near or far an object is from the sensor.
A proximity sensor often emits an electromagnetic or electrostatic field, or a beam of IR radiation, and looks for changes in the field or return signal. The object being sensed is often referred to as the proximity sensor's target. Different proximity sensor targets demand different sensors. For example, a capacitive or photoelectric sensor might be suitable for a plastic target; an inductive proximity sensor requires a metal target. The maximum distance that this sensor can detect is defined "nominal range".
A proximity sensor adjusted to a very short range is often used as a touch switch. A proximity sensor is divided in two halves and if the two halves move away from each other, then a signal is activated.
Usage – Earlier used in rear bumpers of cars to assist while parking. Now used in many smartphones to detect how far the phone is from the user. Eg. During a call, when the user holds the phone near his/ her ear, the proximity sensor deactivates the screen. On taking the phone away from the ear, the screen is re-activated.
3. Ambient light sensor - Ambient light sensors are included in many laptops and cell phones to sense the environment lighting conditions, allowing for adjustment of the screen's backlight to comfortable levels
for the viewer. The range of "comfortable levels" is dependent on the room's light.
Usage - Understandably, a screen's brightness needs to increase as the ambient light increases. What is less obvious is the need to decrease the brightness in lower light conditions-for comfortable viewing and to save battery life.
Other than this, the ambient light sensor is also used for improving the quality of photos that are clicked from the phone camera in a dimly lighted area.
4. Accelerometer - An accelerometer is an electromechanical device that will measure acceleration forces. These forces may be static, like the constant force of gravity pulling at your feet, or they could be dynamic - caused by moving or vibrating the accelerometer. By measuring the amount of static acceleration due to gravity, you can find out the angle the device is tilted at with respect to the earth. By sensing the amount of dynamic acceleration, you can analyze the way the device is moving. At first, measuring tilt and acceleration doesn't seem all that exciting. However, engineers have come up with many ways to make really useful products using them.
An accelerometer can help your project understand its surroundings better. Is it driving uphill? Is it going to fall over when it takes another step? Is it flying horizontally or is it dive bombing your professor? A good programmer can write code to answer all of these questions using the data provided by an accelerometer
High g accelerometers are the industry standard way of detecting car crashes and deploying airbags at just the right time.
A number of smartphones use accelerometers to align the screen depending on the direction the device is held, for example switching between portrait and landscape modes.
It is also useful for auto image rotation, motion-sensitive games, and to correct shake when taking photographs.
Usage – Many apps like Shake Them All, Labyrinth Lite leverage the accelerometer.
You can find a nice tutorial to start using the accelerometer in your apps here
5. Gyroscope - An accelerometer measures acceleration. A 3-axis accelerometer will tell you the orientation of a stationary platform relative to earth's surface, once that platform starts moving, however, things get more complicated. If the platform is in free-fall, it will show zero acceleration. If it is accelerating in a particular direction, that acceleration will simply be added to whatever acceleration is being provided by gravity, and you will not be able to distinguish
Here’s where the gyroscope comes in.
A gyro measures rate of rotation around a particular axis. If a gyro is used to measure the rate of rotation around the aircraft roll axis, it will measure a non-zero value as long as the aircraft is rolling, but measure zero if the roll stops.
So, in a nutshell: Accelerometers are right in the long term but wrong (noisy) in the short term. Gyros are right in the short term but wrong (drifiting) in the long term. You need both--each to calibrate the other--to be right all the time.
I found a good video tutorial that compares the two sensors. The video is by InvenSense, who made the Wii MotionPlus, using Gyroscopes and Accelerometers to capture precise human hand movement.
Usage - Firing Range is one of the best apps that makes use of both the sensors. Do have a look at it.
Asphalt 5 is another great example of how the motion sensors can be leveraged in applications.
Not to mention the very famous ANGRY BIRDS…
6. Magnetometer –
is a measuring instrument used to measure the strength and/or direction of the magnetic field, produced either in the laboratory or existing in nature.
Usage - This one allows the phone to be used as a precise compass. Eg. Super compass and 3D compass
These are but a few uses of the sensors. A lot of research is being carried out to use these sensors in the health care industry, apart from games and apps. There’s a lot of scope to leverage the data generated form these sensors. It’s up to you what you make of these vast resources of data available literally at your fingertips. :-)
