Study of Tactile interactions for visually disabled and hearing

impaired

Supervised by:

Prof. Dr. M.M.A. Hashem

Abu Saleh Md. MusaTaslima Akter

Outline

• Introduction• Problem Statement• Specific objectives • Proposed System Architecture• Software Design• Hardware Design• Expected Results• Timeline• References

Introduction

• Over 21.2 million visually impaired in USA.

• Independent tactile interactions is becoming a bigger challenge.

• Disablers are falling behind.• Sometimes their lives at risk.• device that aids disabled with

Smartphones.

Problem Statement

• Difficult to develop a single device.• GPS not supporting in indoor• Objects are more congested in indoor• Possible Solution:

• Image Processing • IR Sensors & Ultrasonic way finder• New Google Phone(code name “Project

Tango”)

Specific objectives

• To assist physically disabled people. • To navigate for both indoor and outdoor environment. • To detect objects and obstacles in navigation path. • To calculate the threshold value of sensors. • To calculate distance of obstacles using Rangefinder sonar

sensor. • To eliminate noises from the pulse information. • To make a system that employs total support for visually

disabled people. • To perform assistance as hear aid for disabled. • To analyze a system that employs navigational path using

smartphones.

Proposed System Architecture

Software Design

• Initialization and Calibration• Obtaining Range information from

sensors• Median Filtering• Wayfinding Logic• Realtime scheduling

Initialization and Calibration

• ADC and TRT kernel• determines threshold based on the height

of the user.• Three calibration readings at 140ms apart• chooses median value as calibrated value. sensor threshold = sqrt(2) * calibrated

value • holding the tactile sensor at a 45 degree

angle

Obtaining range information from sensors

• simultaneous use of sensor.• Semaphores are used to ensure that.• delay 50ms• require 49ms to obtain a range reading• 8-bit from ADC is converted to distance.• Dis(m)=Vin*(512/5)(in/V)*0.0254(m/in)

=(5/256*ADC)*512/5*0.0254

Median Filtering

• Filter of size 3• effective• Two causes for Impulse noises• Sudden change in ranges• overestimating the distance of an

object

Wayfinding logic

• Two real time tasks• Navigation logic• checks for the presence of obstacles in the

fields of view• object in threshold of 2m, motor will buzz • Tactile sensor logic• checks for obstacles by calibration process• scales intensity of the vibrations

proportionately with the proximity of the obstacles.

Wayfinding Logic

• Pulse duration=1/range*multiplier• For Navigation Logic,• Multiplier=30• & for Tactile Logic• Multiplier=20

Real-time scheduling

• sensors are working independently and simultaneously.

• tactile sensor logic task and ranging tasks have priority over navigation logic.

• navigation logic frequency =300ms • 250ms for all the other tasks.

Software Design

Hardware Design

• Microcontroller

• Motor

• Ultrasonic RangeFinder

• Power

• Smartphone

External Design for Hearing impaired

• Amplified Sound and vibration will indicate command generated by smartphones.

• amplifier circuit will be embedded. • Mini motor vibrator will be used. • Vibration indicates navigational way.

Expected Results

• Faster Detection of Obstacles• Accuracy• User Satisfaction• Safety• User flexibility• Environment independent

Timeline

References

• An acoustic wayfinding device with haptic feedback for the visually impaired, http://people.ece.cornell.edu/land/courses/ece4760/FinalProjects/f2013/xs46_ebl43/xs46_ebl43/xs46_ebl43/webpage.html

• Real-time Mobile-Cloud Computing for Context-Aware Blind Navigation, http://goo.gl/1vI5Ao

• FootPath: Accurate Map-based Indoor Navigation Using Smartphones, http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=6071934

• Ultrasonic range-finder with haptic feedback, http://people.ece.cornell.edu/land/courses/ece4760/FinalProjects/f2013/jjb284_cc697_adk75/jjb284_cc697_adk75/index.html

• Ultrasonic Pathfinder, http://people.ece.cornell.edu/land/courses/ece4760/FinalProjects/f2013/js2587_mg792/js2587_mg792/js2587_mg792/finalProject.html

• Pedestrian Smartphone-Based Indoor Navigation Using Ultra Portable Sensory Equipment, http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5646697