Accelerometer – principle of operation and functionality
Among the most interesting and useful functions of modern smartphones, the automatic screen rotation function, which is provided by a compact device called an accelerometer, deserves special attention. It is this module that supplies the smartphone control unit with information about the position of the gadget in space. In fact, an accelerometer is a device that measures acceleration, which is the difference between gravitational and true accelerations. The main components of the accelerometer are moving mass, a spring that is attached to a fixed surface and a damper. The moving mass is attached to the spring on one side, and on the other hand, the damper dampens its own vibrations. When moving, the mass accelerates and the spring is deformed. Measurement of linear deformations is the basis for the readings of the device. To obtain information about the position of the body in three-dimensional space, three such devices along three axes are combined into one system.
accelerometer operating principle
Features of accelerometers in mobile devices
The main requirement for the accelerometer module for mobile devices is compactness. Obviously, a huge number of microcircuits should be located in a case up to 10 mm thick, occupying a minimum of space. Engineers managed to design a very miniature accelerometer. All structural elements are integrated in a single chip, and the circuit diagram of the design is briefly described as follows. On a fixed housing (1) thin contacts (2) are placed in parallel and on the elastic holders a movable mass (3) is mounted, made in the form of a thin frame with conductors allotted to the sorons and allowing movement within certain limits. Conductors laid to the side are located between the contacts through which the values of the movement of the conductors are taken. The object of measurement is the field strength around the contacts, which changes when the conductors directed toward the movement. It is almost impossible to produce such miniature parts by machining, therefore, chemical processing is used to produce such elements. The production of accelerometers takes place on automated conveyor lines, where the exact time of application and removal of the reagent is crucial.
accelerometer in mobile devices
Functionality and scope
Smartphones and tablets
The pioneer of using the accelerometer was the Nokia 5500 phone, in which the device was used to determine the number of steps taken. But the mass distribution of the accelerometer in mobile devices began after its appearance in the Apple iPhone, after which the presence of such a function became almost the standard for mobile gadgets. In parallel, developers created more and more useful applications using the accelerometer. After the functions of the pedometer, the use of the accelerometer in mobile devices moved to a qualitatively new level when it was already used by the operating system, and also with its help control was implemented in games. Currently, its use is becoming more diverse for various utility applications. For example, using an accelerometer and wireless technology, a number of applications have been created for transmitting information through collision of devices. In modern phones and tablets, the accelerometer is used in combination with gyroscopes, creating extensive opportunities for implementing complex games, such as shooters. There is no doubt that the potential for using an accelerometer is not yet fully disclosed.
Accelerometers are also used in information technology to protect against hard drives dropping and shaking, issuing a control command to the reading heads in a safe position when they fall. Thus, the probability of a disk failure and information loss is significantly reduced.
Control systems for industrial equipment, production lines and units
The task of equipment protection systems is to control vibration with the help of an accelerometer and disconnect it from electrical voltage when critical values are reached.
Car Speedometers and DVRs
If the first ones are used to determine the speed by the mass deviation, the second type of device works on the principle of determining significant events (for example, emergency braking or a sharp change in speed) with their subsequent fixation into separate files.
Aircraft Navigation Devices
It is difficult to imagine helicopters, airplanes, rockets and other types of aircraft without modern navigation systems built using accelerometers and gyroscopes.