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Vibraid: An Innovative Tactile Aid
Our MissionThe aim of this project is to introduce a solution to the issue deaf and hard at hearing people face: limited environmental awareness due to complete or partial lack of sound input. The Vibraid is a cost effective assistive technology capable of compiling the features of many other existing hearing aid devices. It is a waist belt that has the functionality of converting sound into vibration through the use of an array of omni-directional microphones and motors. Through the use of band pass filters, the Vibraid can remove noise signals and is designed to only detect important sounds within specific frequency ranges. Thus, it will allow the user to react quickly to various environmental stimuli - fire alarms, vehicle engines, etc. -, alert them of the direction of incoming threats and ultimately improve their productivity.
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Who We Are
Four Electrical Engineers from Umass Amherst with interests in sound and assistive technologies.
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Block Diagram: Click picture to enlarge
The input block is responsible for picking up all sounds which surround the user. It consists of the four unidirectional microphones, which are biased up and amplified for suitable processing by the Arduino. The input block also implements an envelope detector circuit that rectifies the AC sound signal and produces a DC signal that represents the average ďsound pressure level.Ē This can be used as a comparison measure of sounds in the processing block.
The Arduino is the core of the device. Taking the AC sound signal as an input, it implements an optimized Fast Fourier Transform to determine the fundamental frequency of the sound. If the frequency falls within the user-selected frequency band, the DC sound-pressure-level signals are then compared with each other, to determine the highest average signal sound pressure level among all four microphones. If this highest average exceeds a user-set threshold, the corresponding motor that is associated with the direction of the microphone that received the strongest sound is activated.
The output block consists of four motors. These motors correspond to four different quadrants from which sound can be distinguished between. The processing block will send incoming signals to the output block and activate the motors with an intensity that the user selected. The user will feel the motorís vibration in a specific quadrant, and be alerted of a sound source located in said direction.
The interface block provides the user with a set of switches and knobs which allows them to customize the device to meet specific needs. A sensitivity knob allows the user to set thresholds for which minimum sound can be detected. A motor strength switch will toggle the vibration strength of the motors around the userís waist, to meet the userís sensitivity preferences. The user can customize the device to hone in on specific sounds, through the three filter switches. These switches, which correspond to low, band, and high pass filters, can be combined to create unique combinations of filters.
Preliminary Design Review
Midway Design Review
Midway Design Review Report
Comprehensive Design Review
Final Project Review
Final Project Report
Updates of Vibraid Progress
As of 2/10/2014Initial omni-directional microphones fail to meet desired range specs
Starting 2/10/2014New approach: Time delay estimation
2/11/2014Setup 2-microphone test in quiet room with microphones separated by 10ft
3/2/2014Still working on cross corelation method, results are not consistent.
3/11/2014Our evaluators would like to know how the Vibraid would function outside, as the environment could make it function better or worse.
Performed preliminary testing to quickly determine how the Vibraid functions outside, with little wind.
Discovered a few things, no data to back up findings.
3/13/2014Resumed work on creating filters.
4/16/2014Project coming to a finish
Pictures throughout the year
Checking 2 mic directionality hardware setup
Checking motors with microphone detection logic
Checking 4-way directionality
Testing software approach for 4-way directionality
Getting ready for bench side demo
Testing user interface
Building the first prototype for the Vibraid
Ready for FPR!