Benefits of Virtual Instrumentation:
The very concept of Virtual Instrumentation has made the job of design testing much easier.
Now instead of managing every hardware component, ensuring their functionality and the
final interconnections in the whole design, one can simply design the module on virtual
instrumentation software such as LabVIEW and vary the various design parameters to get the
optimum results making it highly user friendly. Also one can eliminate the need of costly
devices as they can be simulated and the errors can be easily identified and rectified. Virtual
Instrumentation not only makes the designing process simpler but also cheaper. Also as the
concept of virtual instrumentation is based on standard commercial technologies it easily
serves the masses. Thus Virtual Instrumentation enables students, engineers and scientists to
build powerful applications for increasing productivity and performance throughput.
The Challenge:
Developing an automated system for blind persons using proximity sensors aimed to enhance
their understanding of the surrounding through their hearing capacity.
The Solution:
We are putting forth a solution for blind people inspired by echolocation used by bats for
detecting surroundings. Bats produce high frequency sonar waves which after getting echoed
back from various obstacles give information about obstacles ahead. Here we introduce a
signal manipulating control system that aids visually challenged people to know their
surrounding using its smart sensing and feedback mechanism. Proximity sensors are designed
to emit infrared rays and receive the bouncing back rays from the obstacles. The received
wave is converted to voltage and compared with known templates which were stored in
device memory when the device was initially tested at known distances from the obstacles.
Then appropriate directing signal is conveyed via Bluetooth technology to a mobile device
and then is translated in real time into sound signals to guide the person accordingly, for
avoiding obstacles.
Introduction:
There are millions of visually challenged people across the globe dependent on others for
guiding them through pathways. This system is designed to help such people by giving them
an idea of their surrounding using the basic reflection techniques. This thought is inspired by
echolocation used by bats for detecting surroundings. Bats produce high frequency sonar
waves which after getting echoed back from various obstacles give information about
obstacles ahead. Here we introduce a signal manipulating control system that aids visually
challenged people to know their surrounding using its smart sensing and feedback
mechanism. Proximity sensors are designed to emit infrared rays and receive the bouncing
back rays from the obstacles. The output DC Voltage obtained from receiver ADC is fed into
another channel of NI 9201 I/P module. We are making use LABVIEW 8.2 with RT and
FPGA modules. Where there is no object, there is no feedback of echoed rays. The positive
signals are compared with known templates which were stored in device memory when the
device was initially tested at known distances from the obstacles. Then appropriate directing
signal is conveyed via Bluetooth technology to a mobile device and then is translated in real
time into sound frequencies to guide person accordingly for avoiding obstacles.
System Implementation:
The software of the system is basically divided into two Modules: Calibration and
Acquisition Modules.
1) Acquisition Module:
The system setup comprises of a Compactrio with an analog input and output modules. This
enables us in building our application in real-time with high determinism. We have used
Honeywell’s ultrasonic proximity sensors for obstacle distance acquisition.
In order to detect the obstacles we introduce the concept of ultrasonic proximity sensors.
Besides having a detection range of 20 meters, this Ultrasonic Proximity Sensor-946
(Honeywell) has an inbuilt waveform generator of 30 kHz. On detection, these sensors
produce a DC voltage inversely proportional to distance of the obstacle from it, by
programmatically introducing a negative slope for voltage output. This voltage produced is
fed into the Compactrio 9201 (Analog Input Module) to be monitored in LabVIEW.
2) Calibration Module:
This module is used to digitize the voltage input into four levels. The decision of movement
is taken by the output from this module. The output of the receiver is scaled to values 0 or 1
depending on the voltage.
Software Implementation:
We make use of LabVIEW RT and LabVIEW FPGA in our system development. Depending
upon the measurements from Proximity sensors, we can easily visualize the four basic
conditions on the front panel. We can also measure the distance of obstacles from the two
sensors which is calibrated with the output voltage of the sensors. There will be four basic
signals of: move left, move right, move back and no command. Hence, LabVIEW monitors
data from the proximity sensors. After monitoring and comparing data these sensors, it
generates a control signal through the Compactrio analog output module to actuate the voice
signal by earphone connected to mobile using Bluetooth technology. This enables us to
develop a Real-time data acquisition system that is highly deterministic and possess
standalone characteristics.
Figure1:Front panel of VI
Figure2:Block Diagram of VI
System Setup:
The input design consists of 2 proximity sensors transmitter receiver pair. The tranciever
transmits infrared rays which are then received/ absorbed by the receiver after getting reflected
from the obstacles. Now an ADC is used to convert the analog input voltage from the receiver to
a digital value. The digital value is then compared with the stored values in the memory. Finally a
2 bit binary value is computed after the comparisons. This value now is used to select the desired
sound track for the guidance of the person.
The selected sound track is played in a mobile by interfacing through GSM module.
The VI shows the sound track selection procedure. The input of the receivers are polled for after a
certain interval of time. If there is no obstacle there is no audio input to the person, it means he
can go straight.
Theory and Result:
The proximity sensors sense the obstacle distance, and if it measures it to be above a
specified requirement, it gives signal to device to avoid obstacle. Thus the blind person would
come to know of his/her proximity by the device only and hence would intend to avoid it
without the help of others.
Future scope:
The design implemented is a basic model with many simplifying assumptions because of lack of
the available resources. The system can be designed to a level to give a complete picture of the
surrounding using an array of proximity sensors and interfacing the output through Braille code.
References:
1) www.ni.com/India
2) www.honeywell.com
3) www.howstuffoworks.com
4) Computer based electronic Measurement: An introductory electronics laboratory
Workbook; Based on LabVIEW and virtual bench -A. Bruce Buckman
5) Labview Basics 8.1 Training CD1 and CD2
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