University of Illinois

Duke University

Nirupam Roy

Romit Roy Choudhury

Mahanth K Gowda

Haitham Al Hassanieh

Souvik Sen

He Wang

Moustafa Farid

Moustafa Youssef

Ahmed Elgohary

A voice enabled device includes a transducer to capture multiple inaudible signals received from multiple ultrasonic speakers and audio recording electronics to process the multiple inaudible signals to generate digital output samples, which are recorded sound data comprising non-linearities from frequency-shifted versions of the multiple inaudible signals to within an audible frequency range. A processing device is to detect, within the recorded sound data, at least a portion of the non-linearities, e.g., via: comparison of the recorded sound data with expected patterns from an audible audio signal generated by human voice; and detection of non-linear variations within the recorded sound data as compared to the expected patterns. In response to the detection, the processing device is further to suppress an action programmed for response to a voice command corresponding to the recorded sound data.

Causing a voice enabled device to defend against inaudible signal attacks

An audio transmitter includes a first ultrasonic speaker associated with a first channel; a second ultrasonic speaker co-located with the first ultrasonic speaker and associated with a second channel; and a waveform generator to: frequency modulate a first inaudible signal at a first ultrasonic frequency, to generate a modulated inaudible signal; drive, over the first channel, the first ultrasonic speaker with the modulated inaudible signal; and drive, over the second channel, the second ultrasonic speaker with a second inaudible signal at a second ultrasonic frequency so that a combination of the modulated inaudible signal and the second inaudible signal arrive at a microphone system. The second ultrasonic frequency is selected to frequency shift the modulated inaudible signal, upon demodulation by hardware of the microphone system, causing non-linearities of the hardware to translate the first ultrasonic frequency to below a low-pass filter cutoff frequency that is recordable by the microphone system.

Causing microphones to detect inaudible sounds and defense against inaudible attacks

A device includes a coil and magnetic mass movable next to the coil in response to vibrations to generate a back electromotive force signal. An amplifier generates, from the back EMF signal, a vibration signal. A processing device converts the vibration signal to time-frequency domain signal as two-dimensional matrix of frequencies mapped against time slots. Pre-process voiced data of the time-frequency domain signal to generate a reduced-noise signal. Average signal values within a frequency window, and that exist at a first time slot, of the reduced-noise signal to generate a complex frequency coefficient. Shift the frequency window across the frequencies to generate multiple complex frequency coefficients that identify speech energy concentration. Replicate signal values at a fundamental frequency within the voiced data to multiple harmonic frequencies to generate an expanded voice source signal. Combine the speech energy concentration with the expanded voice source signal to recreate original speech.

Vibrational devices as sound sensors

A data receiver includes a vibration sensor to sample data from vibrations in an incoming signal at a predetermined sampling rate, and a microcontroller, coupled to the vibration sensor, to control the sampling rate through an inter-integrated circuit (I2C) protocol or the like. A memory card, coupled to the microcontroller, stores the data with a serial peripheral interface (SPI) protocol or the like.

Communicating through physical vibration

Systems and methods for unsupervised indoor localization are provided. Sensor data obtained from a device carried by a user can be used to simultaneously estimate the indoor location of a user and identify landmarks within the indoor environment based on their signatures. The landmarks can be used to reset the location estimate of the user, and the location estimate of the user can be used to improve the learned location of the landmarks. This recursive process leads to excellent accuracy in indoor localization. Systems and methods for estimating the heading direction of a user are also provided. Sensor data obtained from the user can be used to analyze the forces acting on the user in order to give an accurate heading direction estimate.

Unsupervised indoor localization and heading directions estimation

A data transmitter includes a vibration motor and a switch to regulate voltage from a direct-current (DC) power supply to the vibration motor. A microcontroller generates a pulse width modulation signal with which to drive the switch and regulate the voltage to the vibration motor in a sinusoidal manner, to generate data as symbols from vibrations that form a series of bits from the vibration motor. The microcontroller may also cancel and jam a sound of vibration (SoV) created by the vibration motor. A data receiver includes a vibration sensor to sample data from vibrations in an incoming signal at a predetermined sampling rate, and a microcontroller, coupled to the vibration sensor, to control the sampling rate through an inter-integrated circuit (I2C) protocol or the like. A memory card, coupled to the microcontroller, stores the data with a serial peripheral interface (SPI) protocol or the like.

Growing community of inventors

Urbana, IL, United States of America

Nirupam Roy