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Sensors able to detect three-dimensional motion have been commercially available for several decades and have been used in automobiles, aircraft and ships. However, initial size, power consumption and price had prevented their mass adoption in consumer electronics. While there are other kinds of motion detector technologies available commercially, there are four principle types of motion sensors which are important for motion processing in the consumer electronics market.
Accelerometers measure linear acceleration and tilt angle. Single- and multi-axis accelerometers detect the combined magnitude and direction of linear, rotational and gravitational acceleration. They can be used to provide limited motion sensing functionality. For example, a device with an accelerometer can detect rotation from vertical to horizontal state in a fixed location. As a result, accelerometers are primarily used for simple motion sensing applications in consumer devices such as changing the screen of a mobile device from portrait to landscape orientation. Apple iPhones and the Nintendo Wii incorporate accelerometers.
Gyroscopes measure the angular rate of rotational movement about one or more axes. Gyroscopes can measure complex motion accurately in multiple dimensions, tracking the position and rotation of a moving object unlike accelerometers which can only detect the fact that an object has moved or is moving in a particular direction. Further, unlike accelerometers and compasses, gyroscopes are not affected by errors related to external environmental factors such as gravitational and magnetic fields. Hence, gyroscopes greatly enhance the motion sensing capabilities of devices and are used for advanced motion sensing applications in consumer devices such as full gesture and movement detection and simulation in video gaming. The Nintendo Wii MotionPlus accessory and the Nintendo 3DS incorporate gyroscopes.
Magnetic sensors, commonly referred to as compasses , detect magnetic fields and measure their absolute position relative to Earth's magnetic north and nearby magnetic materials. Information from magnetic sensors can also be used to correct errors from other sensors such as accelerometers. One example of how compass sensors are used in consumer devices is reorienting a displayed map to match up with the general direction a user is facing.
Pressure sensors, also known as barometers , measure relative and absolute altitude through the analysis of changing atmospheric pressure. Pressure sensors can be used in consumer devices for sports and fitness or location-based applications where information on elevation can be valuable.
An example of an immersive musical experience through motion and gesture is accomplished with a musical infrared harp. [1]
A pointing device is a human interface device that allows a user to input spatial data to a computer. Graphical user interfaces (GUI) and CAD systems allow the user to control and provide data to the computer using physical gestures by moving a hand-held mouse or similar device across the surface of the physical desktop and activating switches on the mouse. Movements of the pointing device are echoed on the screen by movements of the pointer and other visual changes. Common gestures are point and click and drag and drop.
A gyroscope is a device used for measuring or maintaining orientation and angular velocity. It is a spinning wheel or disc in which the axis of rotation is free to assume any orientation by itself. When rotating, the orientation of this axis is unaffected by tilting or rotation of the mounting, according to the conservation of angular momentum.
A magnetometer is a device that measures magnetic field or magnetic dipole moment. Different types of magnetometers measure the direction, strength, or relative change of a magnetic field at a particular location. A compass is one such device, one that measures the direction of an ambient magnetic field, in this case, the Earth's magnetic field. Other magnetometers measure the magnetic dipole moment of a magnetic material such as a ferromagnet, for example by recording the effect of this magnetic dipole on the induced current in a coil.
An accelerometer is a device that measures the proper acceleration of an object. Proper acceleration is the acceleration of the object relative to an observer who is in free fall. Proper acceleration is different from coordinate acceleration, which is acceleration with respect to a given coordinate system, which may or may not be accelerating. For example, an accelerometer at rest on the surface of the Earth will measure an acceleration due to Earth's gravity straight upwards of about g ≈ 9.81 m/s2. By contrast, an accelerometer that is in free fall will measure zero acceleration.
A pedometer, or step-counter, is a device, usually portable and electronic or electromechanical, that counts each step a person takes by detecting the motion of the person's hands or hips. Because the distance of each person's step varies, an informal calibration, performed by the user, is required if presentation of the distance covered in a unit of length is desired, though there are now pedometers that use electronics and software to determine how a person's step varies automatically. Distance traveled can be measured directly by a GPS receiver.
An inclinometer or clinometer is an instrument used for measuring angles of slope, elevation, or depression of an object with respect to gravity's direction. It is also known as a tilt indicator, tilt sensor, tilt meter, slope alert, slope gauge, gradient meter, gradiometer, level gauge, level meter, declinometer, and pitch & roll indicator. Clinometers measure both inclines and declines using three different units of measure: degrees, percentage points, and topos. The astrolabe is an example of an inclinometer that was used for celestial navigation and location of astronomical objects from ancient times to the Renaissance.
A vibrating structure gyroscope (VSG), defined by the IEEE as a Coriolis vibratory gyroscope (CVG), is a gyroscope that uses a vibrating structure to determine the rate of rotation. A vibrating structure gyroscope functions much like the halteres of flies.
The Wii Remote, informally referred to with the portmanteau Wiimote, is the primary game controller for Nintendo's Wii home video game console. An essential capability of the Wii Remote is its motion sensing capability, which allows the user to interact with and manipulate items on screen via motion sensing, gesture recognition, and pointing using an accelerometer and optical sensor technology. It is expandable by adding attachments. The attachment bundled with the Wii console is the Nunchuk, which complements the Wii Remote by providing functions similar to those in gamepad controllers. Some other attachments include the Classic Controller, Wii Zapper, and the Wii Wheel, which was originally released with the racing game, Mario Kart Wii.
In computing, a motion controller is a type of input device that uses accelerometers, gyroscopes, cameras, or other sensors to track motion.
A rotational mouse is a type of computer mouse which attempts to expand traditional mouse functionality. The objective of rotational mice is to facilitate three degrees of freedom (3DOF) for human-computer interaction by adding a third dimensional input, yaw, to the existing x and y dimensional inputs. There have been several attempts to develop rotating mice, using a variety of mechanisms to detect rotation.
Angular rate sensors, ARS, are devices that directly measure angular rate, without integration in conditioning electronics. Gyroscopes also measure angular rate. Generally gyroscopes are able to measure a constant rotation rate, while rate sensors also include devices with a low cut off frequency that is other than zero.
In computing, an input device is a piece of equipment used to provide data and control signals to an information processing system, such as a computer or information appliance. Examples of input devices include keyboards, computer mice, scanners, cameras, joysticks, and microphones.
An inertial navigation system is a navigation device that uses motion sensors (accelerometers), rotation sensors (gyroscopes) and a computer to continuously calculate by dead reckoning the position, the orientation, and the velocity of a moving object without the need for external references. Often the inertial sensors are supplemented by a barometric altimeter and sometimes by magnetic sensors (magnetometers) and/or speed measuring devices. INSs are used on mobile robots and on vehicles such as ships, aircraft, submarines, guided missiles, and spacecraft. Older INS systems generally used an inertial platform as their mounting point to the vehicle and the terms are sometimes considered synonymous.
Spacecraft attitude control is the process of controlling the orientation of a spacecraft with respect to an inertial frame of reference or another entity such as the celestial sphere, certain fields, and nearby objects, etc.
An inertial measurement unit (IMU) is an electronic device that measures and reports a body's specific force, angular rate, and sometimes the orientation of the body, using a combination of accelerometers, gyroscopes, and sometimes magnetometers. When the magnetometer is included, IMUs are referred to as IMMUs.
InvenSense Inc. is an American consumer electronics company, founded in 2003 in San Jose, California by Steve Nasiri. They are the provider of the MotionTracking sensor system on chip (SoC) which functions as a gyroscope for consumer electronic devices such as smartphones, tablets, wearables, gaming devices, optical image stabilization, and remote controls for Smart TVs. InvenSense provides the motion controller in the Nintendo Wii game controller and the Oculus Rift DK1. Its motion controllers are found in the Samsung Galaxy smartphones and most recently in the Apple iPhone 6.
In virtual reality (VR) and augmented reality (AR), a pose tracking system detects the precise pose of head-mounted displays, controllers, other objects or body parts within Euclidean space. Pose tracking is often referred to as 6DOF tracking, for the six degrees of freedom in which the pose is often tracked.
An inertial audio effects controller is an electronic device that senses changes in acceleration, angular velocity and/or a magnetic field, and relays those changes to an effects controller. Transmitting the sensed data can be done via wired or wireless methods. To be of use the effects controller must be connected to an effect unit so that an effect can be modulated, or connected to a MIDI controller or musical keyboard. The Wah-Wah effect is a classic example of effect modulation.
Levitation based inertial sensing is a new and rapidly growing technique for measuring linear acceleration, rotation and orientation of a body. Based on this technique, inertial sensors such as accelerometers and gyroscopes, enables ultra-sensitive inertial sensing. For example, the world's best accelerometer used in the LISA Pathfinder in-flight experiment is based on a levitation system which reaches a sensitivity of and noise of .