wrappingS-SENSOR-GYRO.js File Reference

Wrappers for the Gyroscope Sensor. More...

Classes
class	DataGenerator

Functions
function	shake (axis)
function	updateReadings (sensorObject)

Variables
var	previousReading
var	emulateStationaryDevice = (typeof args === 'undefined') ? true : args[0]
var	debugMode = false
const	TWOPI = 2 * Math.PI
var	orig_getters
var	origGetY = Object.getOwnPropertyDescriptor(Gyroscope.prototype, "y").get
var	origGetZ = Object.getOwnPropertyDescriptor(Gyroscope.prototype, "z").get
var	origGetTimestamp = Object.getOwnPropertyDescriptor(Sensor.prototype, "timestamp").get
var	generators
var	helping_functions
var	hc = init_data + orig_getters + helping_functions + generators
var	wrappers

Detailed Description

Wrappers for the Gyroscope Sensor.

See also

https://www.w3.org/TR/Gyroscope/

Author

Copyright (C) 2021 Radek Hranicky

License:

SPDX-License-Identifier: GPL-3.0-or-later

MOTIVATION Gyroscope readings can be used for speech recognition: https://crypto.stanford.edu/gyrophone/ and various fingerprinting operations. For stationary devices, the resonance of the unique internal or external sounds affects angular velocities affect the Gyroscope and allow to create a fingerprint: https://www.researchgate.net/publication/356678825_Mobile_Device_Fingerprint_Identification_Using_Gyroscope_Resonance For moving devices, one of the options is using the Gyroscope analyze human walking patterns: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7071017/

WRAPPING The Gyroscope sensor provides readings of the angular velocity of the device alongthe x/y/z axes. For a stationary device, all velocities should be zero in an ideal state. As we observed on the examined devices, device sensor imperfections andlittle vibrations cause the x, y and z to oscillate between -0.002 and 0.002 on the examined devices. The wrapper simulates the same behavior.

POSSIBLE IMPROVEMENTS Support for simulation of a non-stationary device. This would require modifications to other movement-related sensors (Accelerometer, etc.)

Function Documentation

shake()

function shake

(

axis

)

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updateReadings()

function updateReadings

(

sensorObject

)

Variable Documentation

debugMode

var debugMode = false

emulateStationaryDevice

var emulateStationaryDevice = (typeof args === 'undefined') ? true : args[0]

generators

var generators

Initial value:

= `
    
    var dataGenerator = dataGenerator || new DataGenerator()

hc

var hc = init_data + orig_getters + helping_functions + generators

helping_functions

var helping_functions

Initial value:

= sensorapi_prng_functions
      + DataGenerator + shake + updateReadings

orig_getters

var orig_getters

Initial value:

= `
    var origGetX = Object.getOwnPropertyDescriptor(Gyroscope.prototype, "x").get

origGetTimestamp

var origGetTimestamp = Object.getOwnPropertyDescriptor(Sensor.prototype, "timestamp").get

origGetY

var origGetY = Object.getOwnPropertyDescriptor(Gyroscope.prototype, "y").get

origGetZ

var origGetZ = Object.getOwnPropertyDescriptor(Gyroscope.prototype, "z").get

previousReading

var previousReading

Initial value:

= previousReading || {orig_x: null, orig_y: null, orig_z: null, timestamp: null,
                      fake_x: null, fake_y: null, fake_z: null}

TWOPI

const TWOPI = 2 * Math.PI

wrappers

var wrappers