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Device Capabilities Leveraged in Apps Location, Magnetometer, Motion Sensor, Touch, and Scanner
Published in Jithesh Sathyan, Anoop Narayanan, Navin Narayan, K V Shibu, A Comprehensive Guide to Enterprise Mobility, 2016
Jithesh Sathyan, Anoop Narayanan, Navin Narayan, K V Shibu
An accelerometer is a device used to measure proper acceleration. Proper acceleration is the acceleration measured relative to free fall. The device obtains acceleration due to motion with respect to the earth, and for this, the acceleration is measured relative to a local inertial frame. The device can measure both the magnitude and the direction of the acceleration. Nowadays, the type of accelerometers used in mobile devices is the microelectromechanical systems (MEMS). It is capable of detecting free fall, motion, and wake-up. It has dedicated programmable interrupt lines. Mobile devices usually use a three-dimensional (3D) accelerometer capable of 360° motion sensing, which can be controlled by a software. iPhone uses the LIS331DL MEMS chip for acceleration. It measures acceleration in the range 2—8 g and has shock survivability up to 10,000 g per 0.1 s. Accelerometers are commonly used in modern personal electronic devices such as smart phones, personal digital assistants (PDAs), and digital audio players, tablet PCs, digital cameras, advanced video game consoles such as X-Box and PlayStation. It is mainly used as a motion sensor to rotate the screen in the portrait and landscape modes based on the position in which the device is held. It is used for recognizing tap gestures in the screen or on any part of the device. The accelerometer should be calibrated for optimal use. Usually, the devices will be provided with a calibration button, which when pressed will record new acceleration values. The recorded values are taken as reference for further acceleration inputs and finally normalized for optimum results.
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
It is a device that measures how fast something is moving. Proper acceleration refers to a body's acceleration (rate of change of velocity) in its own instantaneous rest frame, as opposed to coordinate acceleration, which refers to acceleration in a fixed coordinate system. In wearables, accelerometers are employed as sensors. Their detecting abilities are demonstrated by their choice of acceleration, such as gravity and linear. Meanwhile, their ability to measure allows the programming of measured data for many applications. For example, a runner can see his or her speed output and acceleration. Accelerometers can also monitor sleep patterns. They offer a number of applications in industry. Inertial navigation systems for aircraft and missiles use highly sensitive accelerometers. An accelerometer is a type of electrical sensor that controls the acceleration forces acting on it and determines its position to track its movement. The rate of change of an object's velocity, which is a vector quantity, is called acceleration. Static and dynamic acceleration forces are the two forms of acceleration forces. Frictional or gravity forces constantly applied to an item are static. Dynamic forces are “moving” forces that are applied to an object at different speeds. This is why, for example, accelerometers are employed in automotive collision safety systems. When a car is hit by a strong dynamic force, the accelerometer (which detects rapid deceleration) sends an electronic signal to an embedded computer, which activates the airbags. Low power consumption and a cheap price are combined to produce good results [43–46]. Accelerometer sensors are shown in Figure 7.2.
LP-based velocity profile generation for robotic manipulators
Published in International Journal of Control, 2018
First, we prove that the two problems have optimal solution in the same point in a simplified case. In Section 3.2, the LP approach will be extended with the proper acceleration and dynamic constraints. Now, the LP problem is be simplified by eliminating variable ai, and using a special acceleration constraint, where s′i = 1 and s′′i = 1: where , . The two constraints can be rewritten into the following one-sided expressions: From (25) we can construct the following feasible solution : The conditions of bi (25) are equal to the constraints of (24), so is a feasible solution both for the LP and for the SOCP problem. The SOCP problem is created using the same constraints, but a different objective function.
Design and validation of a smart wearable device to prevent recurrent ankle sprain
Published in Journal of Medical Engineering & Technology, 2018
Mohammed Attia, Mona F. Taher, Aliaa Rehan Youssef
This combination in a single module ensures output synchronisation between both sensors. The selection of this IMU was based on its comparison with six other modules (MPU9150, ARDUIMU, 10 DOF IMU, ITG-3200, MMA8452Q and ADXL335). It was selected based on its technical specifications, small size, low power consumption and reasonable cost. In real time, the angular velocity of the foot and proper acceleration are obtained from the gyroscope and accelerometer, respectively. Foot orientation angle is then calculated from proper acceleration values. The presence of DMP reduces the processing time, and thereby the response time of the device and results in better performance [16].
Gap-based automated vehicular speed guidance towards eco-driving at an unsignalized intersection
Published in Transportmetrica B: Transport Dynamics, 2019
After the first section, the target vehicle starts the second section, and the system needs to re-consider if the target vehicle could pass the intersection. If the remaining available gap, TTU1′, is sufficient, the target vehicle will cruise to pass the intersection (see Subscenario 4-(1) in Figure 6); otherwise, the target vehicle will be guided with a proper acceleration/deceleration rate (see Figure 6) using a similar calculation method to Scenarios 1–3.