16-04-2012, 04:57 PM
Electronic Blind Mobility Aid using PSoC
[attachment=20184]
INTRODUCTION:
Many people with visual impairments can travel independently, using a wide range
of tools and techniques. Blind people are faced with many problems such as
independent and graceful travel. A long cane is used to extend the user's range of
touch sensation. It is usually swung in a low sweeping motion, across the intended
path of travel, to detect obstacles. However, techniques for cane travel can vary
depending on the user and/It is well known that visually impaired people use their
hearing sense to compensate for their reduced eyesight. For instance, they can
recognize sound sources. This project focuses on the Electronic Blind Mobility Aid
helps Blind people traveling by themselves using a pair of ultrasonic sensor
mounted on a walking stick.
TECHNOLOGY DESCRIPTION:
Electronic Blind Mobility Aid is composed of a pair of transducers, one transmitter
that transmits echo locating signal and a receiver mounted on the walking stick.
Inaudible ultrasound echoes captured at the receivers are converted into audible
sound induced by the user during his movement from a static object in a range of
15 cm. The resulting audible signal is conveyed to the user through stereophonic
earphones. Whenever an obstacle is found, a beep sound is produced and conveyed
through the earphones. This Aid can be helpful to blind people in spatial sensing by
supplying information during his movement if any obstacle is found. This is less
complicated, simple, portable as it is mounted on the stick, shoe, cap and there is
lesser time lag between the signal transmitted and reception. This also has
disadvantages like interference with the external ultrasonic sources which leads to
the false information.
IMPLEMENTATION:
Blind people run the risk of colliding with an obstacle only when they are in
movement relatively to their environment. This helps in locating the static object in
their path, thereby helping the blind user to travel themselves. This Aid cannot
detect hanging objects as the sensors are mounted on the walking stick which can
detect objects at ground level. To avoid this: We are implementing our system on
shoe and cap. User can be alerted of closed obstacles in range while traveling in
their environment. The system we propose detects the nearest obstacle via an
Ultrasonic sensor system. The system aims at increasing the mobility of visually
impaired people by offering new sensing abilities. Tool used here is PSoCPROGRAMMABLE
SYSTEM ON CHIP.
BLOCK DIAGRAM
DESCRIPTION OF BLOCK DIAGRAM
FREQUENCY GENERATOR: Here we are using three counters which is inbuilt in the PSoC
system. The two counters are used to generate the 40 kHz square wave signal required for
the ultra sonic transmitter. Another counter output is given to the enable input of the third
counter which produces modulated signal with carrier frequency of 40 kHz.
AMPLIFIER: The signal we received from ultra sound receiver is in the range of 20mv which
has to be amplified. This will be done by the PGA block in the PSoC kit. PGA gain has
been set to its maximum. Then its output has been obtained in the range of 3v-4v which is
sufficient for the detection of the signal.
BAND PASS FILTER: It is for the noise removal.
SPEAKER: The speaker is detecting only the envelop of the received modulated signal which is
set in the audio frequency range. This will produce a buzzing sound.
[attachment=20184]
INTRODUCTION:
Many people with visual impairments can travel independently, using a wide range
of tools and techniques. Blind people are faced with many problems such as
independent and graceful travel. A long cane is used to extend the user's range of
touch sensation. It is usually swung in a low sweeping motion, across the intended
path of travel, to detect obstacles. However, techniques for cane travel can vary
depending on the user and/It is well known that visually impaired people use their
hearing sense to compensate for their reduced eyesight. For instance, they can
recognize sound sources. This project focuses on the Electronic Blind Mobility Aid
helps Blind people traveling by themselves using a pair of ultrasonic sensor
mounted on a walking stick.
TECHNOLOGY DESCRIPTION:
Electronic Blind Mobility Aid is composed of a pair of transducers, one transmitter
that transmits echo locating signal and a receiver mounted on the walking stick.
Inaudible ultrasound echoes captured at the receivers are converted into audible
sound induced by the user during his movement from a static object in a range of
15 cm. The resulting audible signal is conveyed to the user through stereophonic
earphones. Whenever an obstacle is found, a beep sound is produced and conveyed
through the earphones. This Aid can be helpful to blind people in spatial sensing by
supplying information during his movement if any obstacle is found. This is less
complicated, simple, portable as it is mounted on the stick, shoe, cap and there is
lesser time lag between the signal transmitted and reception. This also has
disadvantages like interference with the external ultrasonic sources which leads to
the false information.
IMPLEMENTATION:
Blind people run the risk of colliding with an obstacle only when they are in
movement relatively to their environment. This helps in locating the static object in
their path, thereby helping the blind user to travel themselves. This Aid cannot
detect hanging objects as the sensors are mounted on the walking stick which can
detect objects at ground level. To avoid this: We are implementing our system on
shoe and cap. User can be alerted of closed obstacles in range while traveling in
their environment. The system we propose detects the nearest obstacle via an
Ultrasonic sensor system. The system aims at increasing the mobility of visually
impaired people by offering new sensing abilities. Tool used here is PSoCPROGRAMMABLE
SYSTEM ON CHIP.
BLOCK DIAGRAM
DESCRIPTION OF BLOCK DIAGRAM
FREQUENCY GENERATOR: Here we are using three counters which is inbuilt in the PSoC
system. The two counters are used to generate the 40 kHz square wave signal required for
the ultra sonic transmitter. Another counter output is given to the enable input of the third
counter which produces modulated signal with carrier frequency of 40 kHz.
AMPLIFIER: The signal we received from ultra sound receiver is in the range of 20mv which
has to be amplified. This will be done by the PGA block in the PSoC kit. PGA gain has
been set to its maximum. Then its output has been obtained in the range of 3v-4v which is
sufficient for the detection of the signal.
BAND PASS FILTER: It is for the noise removal.
SPEAKER: The speaker is detecting only the envelop of the received modulated signal which is
set in the audio frequency range. This will produce a buzzing sound.