Communicating through physical vibration

Patent metadata

Field	Value
Publication number	US-2016119168-A1
Application number	US-201514920079-A
Country	US
Kind code	A1
Filing date	Oct 22, 2015
Priority date	Oct 22, 2014
Publication date	Apr 28, 2016
Grant date	—

Abstract

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.

First claim

What is claimed is:

1 . A data transmitter comprising:
a vibration motor; a switch to regulate voltage from a direct-current (DC) power supply to the vibration motor; and a microcontroller to generate a pulse width modulation (PWM) 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.

2 . The data transmitter of claim 1 , wherein the switch is a NPN Darlington transistor, the data transmitter further comprising:
a resistor-capacitor (RC) filter to remove distortions from the symbols; and a fly-back diode to smooth out spikes in the symbols, wherein the RC filter and the fly-back diode are located between the switch and the vibration motor.

3 . The data transmitter of claim 1 , wherein the vibration motor causes associated ringing vibrations when driven, and wherein the microcontroller is further to control the vibration motor to apply a small braking voltage a predetermined period of time after being driven to generate a symbol, wherein the predetermined period of time is sufficient for a demodulator of a data receiver to sample the symbol.

4 . The data transmitter of claim 1 , wherein the vibration motor comprises a first vibration motor that generates first symbols along a first axis at a first frequency, further comprising a second vibration motor to generate second symbols along a second axis at a second frequency, the first axis being orthogonal to the second axis.

5 . The data transmitter of claim 4 , wherein the first frequency and the second frequency are non-resonant frequencies between 300 Hz and 800 Hz and are separated by at least 40 Hz to ensure non-overlapping sidebands.

6 . The data transmitter of claim 4 , wherein the microcontroller further comprises:
a first raised cosine filter to filter a first carrier signal; a second raised cosine filter to filter a second carrier signal; an amplitude shift keying (ASK) modulator to modulate the first carrier signal separately from the second carrier signal, to generate a modulated first carrier signal and a modulated second carrier signal; and wherein the microcontroller generates the PWM signal for the modulated first carrier signal and the modulated second carrier to generate the first symbols and the second symbols, respectively.

7 . The data transmitter of claim 1 , wherein the microcontroller is further to transmit a pilot frequency in a pilot carrier signal from the vibrator motor that is transmitted in parallel to the series of bits and to synchronize transmission and reception of the series of bits.

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

9 . The data receiver of claim 8 , wherein the vibration sensor comprises an accelerometer that is in a first-in-first-out sampling mode that queues the data and reads the data in bursts of a plurality of bits.

10 . The data receiver of claim 8 , wherein the predetermined sampling rate comprises 1600 Hz and 10-bit output resolution.

11 . The data receiver of claim 8 , wherein the microcontroller is further to:
detect a pilot frequency in a pilot carrier signal; measure an offset in sampling rate with respect to the pilot frequency; and interpolate the incoming signal to adjust for the offset.

12 . The data receiver of claim 8 , wherein the incoming signal includes a first carrier signal and a second carrier signal along an axis orthogonal to that of the first carrier signal, and the microcontroller is further to:
detect the first carrier signal and the second carrier signal; and save data to the memory card separately for the first carrier signal and the second carrier signal, respectively.

13 . The data receiver of claim 12 , wherein the microcontroller further comprises:
a first raised cosine filter to filter symbols of the first carrier signal; a second raised cosine filter to filter symbols of the second carrier signal; and a demodulator to demodulate the first carrier signal separately from the second carrier signal using, in part, envelope detection.

14 . The data receiver of claim 12 , wherein the second carrier signal includes a first spill onto the first carrier signal and the first carrier signal includes a second spill onto the second carrier signal, and wherein the microcontroller is further to:
amplify the first carrier signal and the first spill, to generate an amplified first carrier signal and an amplified first spill; and add the amplified first carrier signal and the amplified first spill to the second carrier signal and second spill, to cancel out the second carrier signal with the amplified first spill, and to leave an amplified version of the first carrier signal to demodulate free from the first spill.

15 . The data receiver of claim 14 , wherein the microcontroller is further to:
adaptively scale and cancel the second carrier signal to remove an effect of the first spill; and demodulate the second carrier signal.

16 . The data receiver of claim 12 , wherein the vibration sensor comprises an inertial sensor.

17 . A data transmitter comprising:
a vibration motor; a switch to regulate voltage from a direct-current (DC) power supply to the vibration motor; a microcontroller to generate a pulse width modulation (PWM) 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; wherein the symbols cause the vibration motor to emanate a sound of vibration (SoV) that includes data leakage, and wherein the microcontroller is further to generate an anti-noise signal to at least partially cancel the SoV when the SoV emanates; a microphone to detect the SoV; and a speaker to output the anti-noise signal.

18 . The data transmitter of claim 17 , wherein the microcontroller is further to model the anti-noise signal by:
before generating the PWM signal, transmitting a brief symbol; detecting a fast Fourier transform (FFT) of an SoV of the brief symbol; selecting a top predetermined number of strongest overtones within the FFT; combining the top predetermined number of strongest overtones into a revised signal model in a frequency domain; converting the revised signal model to a time domain to generate a converted signal model; and generating an inverse of the converted signal model.

19 . The data transmitter of claim 17 , further comprising a receiver coupled to the microphone to sample the SoV at a determined frequency, wherein the microcontroller is further to:
output the anti-noise signal close to timing of the SoV; increase sampling frequency such that a fundamental frequency of the anti-noise signal increases by δf; detect a phase-lock between the anti-noise signal and the SoV; and reduce sampling frequency by δf back to an original sampling frequency, but matching phase with the SoV.

20 . The data transmitter of claim 17 , wherein a residue of the SoV remains after the speaker outputs the anti-noise signal, wherein the microcontroller further to:
model the anti-noise

Assignees

• Univ Illinois

Inventors

• Roy Nirupam
• Choudhury Romit Roy
• Gowda Mahanth K

Classifications

• H04B1/0475

  with means for limiting noise, interference or distortion (H04B1/0483 takes precedence) · CPC title

• H04L25/4902 Primary

  Pulse width modulation; Pulse position modulation · CPC title

• H04B1/16 Primary

  Circuits · CPC title

• H04B1/04

  Circuits · CPC title

• H04B11/00

  Transmission systems employing ultrasonic, sonic or infrasonic waves · CPC title