Motion sensor in the phone. What is a Hall sensor in a smartphone? All sorts of sensors are needed
Modern phones are very similar to computers - they are arranged according to general principle: motherboard, processor, video adapter RAM.
But the main difference is the numerous sensors that no smartphone can do without: accelerometer, gyroscope, barometer, temperature sensors, proximity light, etc. They all make your phone easier to use and smarter. Today we will tell you about the features and purpose of the magnetic sensor in modern smartphones.
Why do you need a magnetic sensor?
This sensor is also called. The Hall effect was discovered almost 150 years ago, but it is actively used in various techniques to this day. The Hall sensor detects a magnetic field, so it can determine the position of the smartphone in space. So, a smartphone - just download special application from Google play(just search for "compass").
In the middle of the last century, the Hall sensor was used in cars - this was the first step in introducing such technologies into human life. Further, the development began to be used in other areas, including mobile technologies.
The magnetic sensor is convenient when combined with a magnetic snap / snap case. Due to this, you can save time, since the phone screen will automatically turn off when you close it and turn on when you open the accessory. If the cover has a window, the space uncovered by it can be active, that is, it will be possible to check the time, applications and some widgets without opening the case and unlocking the smartphone. It should be noted that the magnet does not harm the sensor or other sensors or phone components in any way.
How do I turn on the magnetic sensor on my phone?
Most flagships from both big brands and budget companies have a magnetic sensor. It works automatically. You can check the availability of technology in technical characteristics a specific device or thanks to simple tests:
- You can simulate a magnetic case by attaching an ordinary magnet to the phone screen. If the display goes out, the magnetic pickup has been triggered.
- Download the compass app, turn off the internet and check if it works. UPD. It should be noted that in the case of the compass it comes about a more advanced geomagnetic sensor.
A modern smartphone is not just calls and SMS, but much more. But today we will not talk about how to go online from these devices, not about their hyper-communication capabilities and not about the advantages of a particular mobile operating system. The article will be devoted to the sensors and sensors that developers equip modern devices to make their functionality even more diverse. So what are gauges and sensors? These are microdevices in the smartphone itself (player, tablet, navigator, laptop, digital camera, game console, etc.) that make it smart and also communicate with outside world... Without them, the smartphone will not be so interesting and in demand, since the gadget will be without connection with the environment. It is with the help of sensors and sensors that a connection with the world around appears, which means that new amazing functions appear.
Of the main sensors and sensors known to many, and without which today only very budget mobile phones can not do, the following can be distinguished:
1. Proximity Sensor
2. Accelerometer
3. Light Sensor
4. Gyroscope Sensor
5. Magnetic Field Sensor (a magnetic compass is usually not considered a sensor, but we still included it in the list)
Proximity Sensor
The proximity sensor allows you to determine the approach of an object without physical contact with it. For example, a proximity sensor installed on a mobile phone can turn off the backlight when the phone approaches the user's ear during a call. That is, its main task is to block the smartphone so that the user does not accidentally press, say, with his cheek to hang up. By the way, in this case the charge is also saved. battery... Naturally, manufacturers are trying in every possible way to expand the capabilities of this function. For example, a year ago in Samsung Galaxy S3 introduced the "Direct Call" function, which, when the device is held up to the face, allows you to call a contact whose information, call log or message data is displayed on the screen. Also, a phone with this sensor can be safely put in a pocket or case, without fear of accidentally making an unnecessary call.
In general, motion control is the next stage in communication between man and technology, on which a lot of manufacturers are working today. For example, last year Pioneer introduced the lineup car multimedia and navigation GPS-systems, which can be controlled using gestures. Pioneer named its development "Air Gesture". If the user brings his hand to the front of the screen of the multimedia and navigation system, it displays a window with the name of the displayed in this moment compositions and frequently used control commands: "Set as destination" and "Set favorite place as destination". As soon as the user takes their hand away from the screen, these commands disappear, and navigation map will be displayed on the full screen again. In addition, by moving the hands horizontally, certain user-defined functions can be invoked without pressing a button. You can set one of 10 functions, including "Switch between navigation and AV function" and "Skip current song / Play previous song". The sensor, which detects hand movements, consists of two infrared emitting parts and one receiver between them. When the hand moves to the front of the screen, the receiving IR sensor detects reflections of infrared light. With a horizontally moving hand, the IR sensor detects the change in the timings of infrared radiation from the right and left emitting parts so that it becomes clear in which side the hand is moving. By the way, the production of models with user interface Air Gesture gesture control has already begun.
The same feature is implemented in the new flagship Samsung Electronics - Galaxy S4. In addition to the proximity sensor, next to front camera there is another sensor that is used for gesture recognition. It recognizes hand movements by receiving infrared rays that bounce off the user's palm and works in tandem with the Air Gesture feature, giving users the ability to answer a call, change songs, or scroll up or down a web page with just one wave of the hand.
Accelerometer
Perhaps this is the most common sensor. The G-sensor, as many manufacturers call it, can be found in almost every modern device today. The task of the accelerometer is simple - to track the acceleration that is given to the device. It seems that the question arises, why measure the acceleration of a smartphone? But let's think about it, the moment we turn the phone over, there is an acceleration movement. The accelerometer registers it and, based on the data received from it, starts a process, for example, changing the screen orientation. The sensor is also used to scale browser pages when the smartphone is tilted, updating the list of Bluetooth devices when shaken, in specific applications, and, of course, in games, especially in simulators. In addition, the accelerometer is used as a pocket foot pod for counting the number of steps taken by the user.
In cameras, the accelerometer is used to rotate the captured frame, and in laptops - for urgent parking of the heads. hard disk if suddenly the computer crashes. And in cars, it serves to deploy the airbags on impact. Simply put, the accelerometer deals with the position of the device in space and the tilt of the body, while relying on its acceleration when changing this position.
Light Sensor
The tasks of this sensor are extremely simple and are to determine the degree of ambient light and adjust the brightness of the screen accordingly. Thanks to this automatic brightness adjustment, it is possible to save energy, especially if you want to optimize the consumption of your battery. Perhaps this is the oldest sensor in mobile world, and even though this sensor does not seem to have any opportunities to improve functionality, manufacturers in this case are trying to make working with a smartphone even more comfortable.
For example, in mobile operating system iOS 6 from Apple introduced the ability to adjust auto brightness. Previously, the light sensor was fully automated and adjusted the brightness of the screen at its discretion. Now the user has the opportunity to control the operation of this sensor. You can easily determine the brightness level that is comfortable for you, and iOS takes that choice into account when calculating the brightness level for new lighting conditions. However, in order for the sensor to function correctly, it is necessary to make a small adjustment to the device.
Gyroscope Sensor
If the capabilities of the accelerometer are by and large exhausted, and the scope of its application is clearly limited, then the device of another inertial sensor, which is a gyroscope, has not yet been fully mastered in smartphones. The history of the use of gyroscopes dates back to the end of the 19th century. At that time, inertial sensors were common in the fleet, since with the help of a gyroscope it is most accurately possible to determine the location of the cardinal points. Later, thanks to such a unique function, the gyroscope became widespread in aviation. By its design, the gyroscope in mobile phones resembles classic rotary ones, which are a rapidly rotating disc mounted on movable frames. Even if the position of the frames in space is changed, the axis of rotation of the disk will not change. Due to the constant rotation of the disk, for example, with the help of an electric motor, it is possible to constantly determine the position of an object (in which there is a gyroscope) in space, its tilts or rolls.
Gyroscopes in modern devices are based on a microelectromechanical sensor, but the principle of operation of the inertial sensor remains the same. The same family includes accelerometers, magnetometric and other highly specialized sensors. The market for these diminutive elements, also known as MEMS, received a major boost when Apple began installing a gyroscope in the iPhone 4, and then in iPod Touch... Successful sales of mobile devices have led MEMS element manufacturers to successfully settle in mobile market. Apple iPhone 4, which pioneered the use of a gyroscope and two MEMS microphones for noise cancellation, had a huge impact on the phone industry. For example, at the end of 2010, fewer than five phones on the market boasted a gyroscope, and in 2011 there were already more than 50 models of phones and tablets with a gyroscope.
Gyroscopes built into mobile phones make the quality of games the highest. With this sensor, you can use not only the normal rotation of the device to control the game, but also the rotation speed, which provides more realistic control. In addition to games, the gyroscope is used in augmented reality browsers for more accurate positioning of the device in space, as well as in radio models of aircraft controlled using smartphones on iOS and Android platforms.
Magnetic Field Sensorcompass)
After the arrival of GPS receivers in our world, digital compasses also appeared, however, in the era of the development of navigation technologies, they are not so useful. The magnetometer, like the usual magnetic compass, tracks the orientation of the device in space relative to the earth's magnetic poles.
The information obtained from the compass is used in mapping and navigation applications. In practice, this device has shown itself quite well and today is indispensable in a number of games and applications, for example, in the Layar augmented reality browser.
Other sensors and sensors
Barometer
This sensor also helps with positioning. The barometer started appearing in smartphones quite recently, with the release of the Samsung Galaxy Nexus, and can reduce the time it takes to connect to a GPS signal. The built-in barometer measures the atmospheric pressure at the current location of the smartphone owner and determines the altitude. Many flagship smartphones today are equipped not only with GPS and GLONASS receivers, but also with a barometer, so that the signal from the satellite is captured and the initial location is determined instantly. This function is also useful when the user moves on inclined planes, be it a hill or a mountain, because depending on the atmospheric pressure and altitude, he can calculate the exact number of calories that are burned during a walk. Well, and, accordingly, to determine the pressure and weather conditions directly from your smartphone.
Let's consider the principle of operation of this sensor using an example Samsung smartphone Galaxy S III, where the determination of the pressure difference can be recalculated about 25 times per second. This speed makes it possible to clearly determine the movement of a person up and down, that is, to use navigation not only in the horizontal plane, but also in the vertical one. Thus, we get a volumetric navigation that is fully consistent with reality. For example, when navigating to mall a regular GPS navigator will not be enough for you, as it will indicate a point on the plane of the earth, and not at what altitude your route is. And car navigators can navigate in multi-storey parking lots and multi-tiered roads.
The pressure sensor allows you to do this, and you will receive not only the exact coordinates of a given place, but also information on which floor or height your route lies. Typically, such sensors include a data processing system, and their dimensions are within 3x3x1 mm. The tiny sensor reacts to changes in height with an accuracy of 50 cm. The technique is implemented by comparing external atmospheric pressure with respect to the vacuum chamber inside the sensor. In addition to the vacuum chamber and sensors, a built-in microprocessor, an analog amplifier, a digital co-processor, and a non-volatile memory element were placed in the miniature body of the device.
Temperature / humidity sensor
This sensor is a new addition to the Samsung Galaxy S4. It detects ambient temperature and humidity levels through a small hole located at the base of the smartphone. The sensor then determines the optimal comfort level and displays this information on the S Health app screen. In addition, the temperature sensor allows you to correct pressure errors caused by changes in air temperature. Those who want to immediately take advantage of the capabilities of the temperature sensor can pay attention to the development of scientists at Robocat.
They created a tiny Thermodo electric thermometer that connects to the phone via a headphone port. Thermodo consists of passive temperature sensors built into a standard 4-pole headphone jack in robust housing... No network connection is required, the device is powered by the phone and consumes little power. When temperature measurement is not required, Thermodo can be hung on the keys like a key fob. With Thermodo you can measure the temperature both indoors and outdoors.
3D sensor
A sensor that continuously scans the surrounding area and creates a computer virtual model with high precision. Something similar is the Kinect, but a new version The Google Nexus 10 tablet received a sensor much more compact and there are already ready-made applications that can work on the tablet and demonstrate the capabilities of not only the most modern games.
Among other things, the Capri 3D sensor, which was presented at the Google I / O 2013 conference by PrimeSense, is able to register movements and obtain metric parameters of objects. Incidentally, this development of this technology proves IBM's assumption that in the middle of this decade, communication using video conferencing applications will begin to resemble 3D holograms.
Security
Recently, Professor of Swarthmore College (Pennsylvania, USA) Adam J. Aviv demonstrated the possibility of carrying out attacks using data obtained from a smartphone accelerometer. It turned out that the data obtained by the smartphone's sensors can help attackers gain access to the device's unlock codes. They can find out the pin codes and passwords of the user. Receiving information through sensors is much easier than through applications downloaded to a smartphone, says the professor. The researchers analyzed the data obtained by the accelerometer and compiled a kind of "dictionary" of smartphone movements when entering a password, after which they developed software, which allows decrypting Pin-codes using data obtained from an accelerometer. In the course of research, scientists were able to correctly identify the Pin-code in 43% of cases, and the password in 73%. The system malfunctions when the user is in motion while using the device, as movements create additional interference, and it is very difficult to obtain accurate data from the accelerometer.
Mobile security experts also believe that the more sensors a smartphone has, the more data they can capture, which means that the problem of protecting the device becomes more acute. Researchers are now developing methods to prevent leakage of data collected by gyroscopes, accelerometers, or other sensors. So it can be assumed that with the development of technology and the expansion of the functionality of sensors, the security situation will only escalate.
Perspectives
Recently American inventor Jacob Fraden founded Fraden Corporation and patented the system contactless measurement temperatures for mobile devices. On the back of the smartphone is a small infrared sensor that can take readings of the user's body temperature in just a second. Thus, in the future, smartphones may well turn into our personal medical assistants. Fraden also intends to create instruments for measuring ultraviolet radiation and electromagnetic pollution. But employees from the Next Lab at the Massachusetts Institute of Technology claim that sensors in smartphones will soon be able to detect arrhythmias and tachycardia, which will force users to seek medical help in a timely manner.
According to experts from IBM, smartphones will have a sense of smell by 2017. Tiny odor sensors can be built into smartphones and other mobile devices. The detected traces of chemical compounds will be transmitted to a powerful cloud application capable of analyzing everything from carbon monoxide to the flu virus. As a result, if you sneeze, your phone can tell you about your illness.
All the most interesting is just beginning, and today work is going on in a variety of areas. For example, it is possible that in the near future your smartphone will learn to simulate tactile sensations using a certain kind of sensors. You will be able to distinguish between fabrics, textures and weaves. And sound sensors combined with massive cloud computing systems will have superhuman hearing capabilities. Oh, what can not be assumed, especially since the mass of assumptions, calculations and even fantasies in recent years began to come true with an amazing speed.
To implement correct work modern mobile phones use various functional blocks and information sensors. On their basis, the systems higher in the hierarchy make decisions about certain actions. Today we will talk about a measuring element that determines the presence of a magnetic field, its intensity and change.
Outstanding physicist Edwin Hall in the United States at the end of the 19th century discovered the phenomenon of curvature of the path of charge carriers in semiconductors in a magnetic field. The Hall effect has great opportunities... It tracks the orientation of the screen in space, and measures the magnetic polarity in rocket engines. The sensors work perfectly in proximity switches and liquid level detectors.
To measure the voltage of the magnetic field, 2 types of devices are used: analog and digital sensors. In the first type, the field induction is converted into voltage, where the value depends on the strength and polarity. In the second case, when the polarity changes and the induction decreases, the sensor turns off the touch screen.
The miniature sensor found its main application in digital gadgets to improve their positioning, to provide quick start GPS navigator. Distinctive feature this device is a versatile direction of action:
- With its help, the magnitude of the magnetic flux changes;
- Contactless control using gestures is implemented;
- The brightness of the screen is automatically adjusted to the change in illumination;
- The orientation of the image on the display changes with the corresponding rotation of the gadget, manipulation in games and other applications;
- The exact direction is determined.
Of course, this is not the whole list. positive characteristics inherent in this sensor.
Why is a Hall sensor needed in a smartphone?
The sensor, as a highly sensitive part of the broadcaster, is located directly under the cover of a smartphone or tablet, which allows you to quickly respond to any changes in space. The sensor saves battery power, improves the interaction of the phone with the magnetic case and various accessories.
Clamshell phones also use Hall sensors. Their presence makes it easier to turn on / off the screen while opening or closing the protective cover. A similar action occurs with a smartphone with a magnetic case, where the sensor reacts with lightning speed to changes (approach / removal) of the magnetic field on the flip and registers it. During intense radiation, the display is blocked, when it decreases, it is activated. At the same time, the magnet itself, mounted in the flip of the case, does not harm the smartphone at all.
The Hall effect is especially characteristic in cases with a window at the top, where part of the screen remains open. In this case, it is possible to use individual functions (call, missed calls, clock, player) without opening the flip. The magnetoelectric device will independently determine whether to leave the entire display active or partially. The gadget works in a similar way when using covers without "windows".
When purchasing a new smartphone, you can independently determine the presence or absence of a Hall sensor. It should be noted that not all manufacturers indicate its presence, so you need to carefully study the short list of characteristics. The device is found by another method, after analyzing the covers to your mobile device... For example, the Smart Case cover for a smartphone or tablet has a 100% Hall sensor installed. The analysis of other covers is carried out by analogy.
Gadgets are equipped with a wide variety of sensors that open up new functions and make the use of phones easier and more comfortable.
We have already compiled with which smartphones are equipped, but did not mention the Hall sensor. What it is, what it is for and how it works - all this can be found in this article.
Why do you need a Hall sensor?
This sensor is capable of sensing position and is based on the Hall effect, which was discovered in 1878. The physicist managed to make a discovery by measuring the voltage of the current in a conductor that was in a magnetic field.
Our gadgets use a simplified version of the Hall sensor. It is able to determine the presence of a magnetic field, but does not calculate the field strength along different axes. Together with it, a magnetic sensor is often used on smartphones, which is responsible for the operation of the compass.
Hall sensor in smartphones
Hall sensor can be found mainly in flagship smartphones for which are available special covers with magnetic closure - often referred to as smart cases or Smart Cases. The sensor is able to determine whether the cover of the case is closed or open, and in accordance with this, enable / disable the display of the device.
It should be noted that not all manufacturers indicate the presence of this sensor in the characteristics of the device. Precisely in the presence of this sensor, you can be sure if Smart Cases are available as accessories for the gadget.
Hall sensor helps navigation programs measure location faster. Previously, it was used in clamshell phones and helped activate the screen when the gadget was opened and turn it off when the device was closed.
Other application
Hall sensors were originally used in cars where they were responsible for measuring the angle of the crankshaft position. The sensor detects the moment when a spark has formed in the car. True, this applies to old cars. Later, the sensor began to be equipped with proximity switches and liquid level meters. They were also used in magnetic code reading systems and even in rocket engines.
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An orientation sensor is a combination of a magnetic field sensor, which acts as an electronic compass, and an accelerometer, which measures tilt and rotation.
If you are familiar with trigonometry, you can independently calculate the necessary data and determine the position of the device relative to all three axes, based on the readings of the accelerometer and the magnetic field sensor. However, the good news is that Android can do all the calculations on its own.
Using a standard reference system, the position of the device is calculated in three dimensions. As with the accelerometer, the device is viewed at rest, with the screen facing up on a flat surface.
X axis(direction). The direction of the device when moving around the X axis; 0 ° / 360 ° - North, 90 ° - East, 180 ° - South, 270 ° - West.
Y-axis(incline). The angle of inclination of the device when rotating about the Y axis. It equals 0 ° if the device lies on the back cover, –90 ° if it is placed vertically ( top part device points up), 90 ° if upside down, 180 ° / -180 ° if facing down.