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IoT and Wearable Sensors for Health Monitoring
Published in Rashmi Gupta, Arun Kumar Rana, Sachin Dhawan, Korhan Cengiz, Advanced Sensing in Image Processing and IoT, 2022
Radhika G. Deshmukh, Akanksha Pinjarkar, Arun Kumar Rana
A magnetometer is a device that measures magnetic dipole moment or magnetic field. Magnetometers measure the direction, strength, or change in the strength of a magnetic field at a specific area. For inertial measurement unit (IMU), they can be used with accelerometers and gyroscopes. All these sensors have three axes, work similarly to a compass, and can help with balance. Magnetometers match them by filtering the motion orientation, but gyroscopes and accelerometers are commonly employed along with them. A magnetometer sensor is shown in Figure 7.4.
Petroleum Geophysical Survey
Published in Muhammad Abdul Quddus, Petroleum Science and Technology, 2021
A magnetometer is an instrument for determining the magnetic field. It may be noted that variation due to instrument drift is minimal and not significant as compared to other geophysical measuring instruments. The instruments are robust and sturdy. Descriptions of four different magnetic instruments are given below.
IoT End Devices
Published in Rebecca Lee Hammons, Ronald J. Kovac, Fundamentals of Internet of Things for Non-Engineers, 2019
Magnetometer—Devices that measure magnetism direction, strength, or change in a magnetic field. A typical compass would be an example of a magnetometer. These magnetometers can be used to detect metal objects at a far greater range than the typical metal detector, which operates based on a different principle. Magnetometers have become miniaturized and can be incorporated in integrated circuits at a very low cost (MEMS magnetic field sensors).
A review of medical wearables: materials, power sources, sensors, and manufacturing aspects of human wearable technologies
Published in Journal of Medical Engineering & Technology, 2023
Mohammad Y. Al-Daraghmeh, Richard T. Stone
Gyroscopes are typically used to measure angular velocity, and the proof mass is pushed back and forth by driving combs. A rotation of the gyroscope generates a Coriolis force acting on the mass, which results in a motion in a different direction. The motion in this direction is measured by electrodes and represents the turn rate [68]. Gyroscopes are used in applications such as wearable balance assistance devices for the elderly for postural control and preventing falling [69–71] proposed a head movement system based on gyroscope of wearable tool for hands-free manipulation of an electric-powered wheelchair for the disabled. Magnetometers is a simple sensor that measures magnetic fields and the magnetisation of materials based on the electromagnetic property of the earth. Which is also utilised to measure the direction, strength, or relative change of a magnetic field at a given location. Gyroscopes can be used to monitor millimetre night-time breathing movement by measuring the difference in the magnetic vectors to enhance the quality of sleep [72]. Human activity detection systems using wearable accelerometers, magnetometers, and gyroscopes sensors have been discussed extensively in the research to assist patients, enhance their rehabilitation process and improve their quality of life [73,74]. However, the ideal combination of sensors for a specific purpose has been investigated by many researchers. For example, [75,76] concluded that the accelerometer signal is the only significant input in wearable fall detection systems, and the gyroscope signals can be ignored.
Validity of inertial measurement units for tracking human motion: a systematic review
Published in Sports Biomechanics, 2021
John Ghattas, Danielle N. Jarvis
The IMU functions to track human motion through the use of four main devices: a gyroscope, an accelerometer, a magnetometer, and a signalling device (Pratt & Sigward, 2018). The gyroscope is responsible for providing the system with information about the general change in angular velocity of the IMU attached to the body segment. The accelerometer provides information about both the linear and gravitational accelerations that the specific segment is experiencing. The magnetometer helps provide the system with a ‘real-world’ orientation by measuring the earth’s electromagnetic field relative to the device, similar to a compass. Lastly, the signalling device serves to transmit the raw data to a device capable of analysing and interpreting the information it receives. This back-end analysis, and ultimately kinematic data production, is accomplished through the application of complex algorithms that have the ability to interpret the raw data and combine information from multiple IMUs to provide insight into what is occurring (Robert-Lachaine et al., 2017).
A similarity-based neuro-fuzzy modeling for driving behavior recognition applying fusion of smartphone sensors
Published in Journal of Intelligent Transportation Systems, 2019
Hamid Reza Eftekhari, Mehdi Ghatee
Based on these conditions, the accelerometer, the gyroscope and the magnetometer, which are referred as Inertial Measurement Unit (IMU) sensors, are good options. In contrast to the sensors like GPS, which are turned on by a user or an application, IMU sensors are always activated. In the following, some details are stated from (2700-2017-IEEE Standard for Sensor Performance Parameter Definitions, 2018):Accelerometer: This is a sensor that measures the rate of change of velocity with high accuracy in recording the smallest changes in acceleration and gestures along the three directions of the device. This sensor is a good candidate to determine vehicle acceleration because of its high updating rate. Also, this sensor consumes low energy and it is always turned on.Magnetometer: This sensor measures magnetic field. For example, this sensor can sense the magnetic field around the earth or magnetic objects. By fusion of this sensor and the gyroscope, one can detect the angle between the device and the coordination axis of the base (Renaudin, 2010). This sensor also consumes low energy.Gyroscope: This sensor measures rotation velocity. By this senso, one can detect the rotation of vehicle. Some studies have used this sensor, together with the accelerometer, as a complementary sensor, see e.g., (Bejani & Ghatee, 2018).