guiding visually challenged using avr microcontroller
TRANSCRIPT
GUIDING VISUALLY CHALLENGED USING AVR MICROCONTROLLER
Presentation byDig Vijay Kumar Yarlagadda
Contents• Introduction• Block Diagram• Sensor Module• Microcontroller Section• Voice Module• Operation• Advantages And Disadvantages• Applications• Project Overview• Conclusion• References
Introduction
• Disability is a curse to a person especially if the person is blind.
• Every five seconds a person turns in the world to blind.
• The number of the blind in the world is currently estimated at 45 million
people.
• Nine million blind and visually impaired people live in India.
Current technologies
Electronic Eye Laser caneWalking stick
• "Guiding Visually Challenged Using AVR Microcontroller" mainly focuses on
providing guidance system for blind people to avoid any stationary obstacles.
• In contrast to many existing technologies, the device is designed to be portable,
user friendly and inexpensive.
Project overview
Block diagram
Voice moduleSensor moduleMicrocontroller
section
Fig. Block diagram of Guiding Visually Challenged using AVR Microcontroller
Sensor module
Fig. Circuit Diagram of Sensor module
Sensor module(contd.)• Sensor module mainly consists of a quad operational amplifier LM324 and
three IR Transmitter-Receiver pairs.
• The light is illuminated from IR Transmitter continuously and if any obstacle is
encountered, the light is reflected back and corresponding receiver receives
the signal.
• Op-amp compares the received output to a preset value and if the received
output is greater, it sends a HIGH voltage to Microcontroller section for
processing.
Microcontroller section
Microcontroller section(contd.)• ATmega8 is a 8-bit Microcontroller based on the
AVR RISC Architecture.
• It can execute powerful instructions in a single clock
cycle.
• In order to maximize performance and parallelism,
the AVR uses Harvard architecture, which separates
memories and buses for program and data.
Features of ATmega8• High-performance 8 bit Microcontroller
• 32 x 8 General Purpose Working Registers
• Six ADC channels in PDIP package
• Internal Calibrated Oscillator
Voice module
Voice module(contd.)• Voice module consists of IC AP89042 and IC LM386.
• The IC AP89042 is a high performance Voice OTP with embedded 1M bits
EPROM.
• It can store up to 42 sec voice messages with 4-bit ADPCM compression at 6KHz
sampling rate.
• The LM386 is a low voltage audio power amplifier consisting of with a gain of 20-
200.
Operation• The IR transmitter-receiver pairs are mounted on the left, front and right side
of the hand stick and they transmit IR signals regularly.
• The corresponding receiver receives back the signal if it is reflected by some
obstacle in that particular direction.
• The received signal is fed to corresponding operational amplifier of IC LM324.
• Output of each operational amplifier is limited to 3.3V by zener diodes and is
given to Microcontroller for further processing.
• The AVR Microcontroller detects the direction from which the signal is
received and issues suitable audio message.
• The audio message is amplified in voice module and fed to the speaker.
Operation(contd.)
Circuit
• Inexpensive
• Portable
• User friendly
Advantages
• Device may not work when obstacles are mobile
Disadvantages
Applications
Project
ConclusionThe device can be employed as an guidance system for visually impaired and blind
people.
References[1]. Sunil kumar, "Guiding visually challenged using Raspberry Pi", Electronics for
you, March 2014.
THANK YOU