Mobility for the blind is always a great problem. Just like a sighted, blind also needs to travel around inside
a closed premises like house, factory, office, school etc. They may also like to go for shopping, visiting friends and other places of their interest Presently available electronic travelling aids like sonic path finder, sonic torch etc. are not suitable for using inside a closed premises such as school, factory, office etc.
Blind since old age have been using walking stick for their mobility purposes. In addition some of them are also using guide-dog for their mobility. Due to the development of modern technologies, many different types of devices are available to assist the blind. They are commonly known as electronic travel aid. Many of these travelling aids use either ultrasound or laser beam. One of such devices is the laser cane that is similar to a long cane with built-in laser ranging facilities. But most of the commonly used electronic travelling aids use ultrasound for functioning. These devices use the reflectance property of the high frequency ultrasound and are available in different models such as:
A. Sonic torch
It is battery operated and is about the size of a large electric torch. It is a hand held device and operates on the principle of transmitting ultrasound in the forward direction and receiving the reflected beam from a nearby object.
B. Mowat sensor
It is a light weight,'hand held, pocket size device and is quite similar to a common torch that is used by the sighted people. It can detect object by sending high frequency ultrasound in pulses and receiving the reflected beam from any nearby object. User can identify the distance of the object by the rate of vibration that is produced by the device.
C. Sonic pathfinder
Like a Mowat sensor a sonic pathfinders also identify an object by receiving the reflected ultrasound that is emitted by the device. But unlike Mowat sensor which is a hand held device a sonic pathfinder is to be fitted on the head of the user. The audio output from the sonic pathfinder is made up of notes of a musical scale which produce a familiar tonal progression as the user approaches an object, is fed to the user through earphones.
a closed premises like house, factory, office, school etc. They may also like to go for shopping, visiting friends and other places of their interest Presently available electronic travelling aids like sonic path finder, sonic torch etc. are not suitable for using inside a closed premises such as school, factory, office etc.
Blind since old age have been using walking stick for their mobility purposes. In addition some of them are also using guide-dog for their mobility. Due to the development of modern technologies, many different types of devices are available to assist the blind. They are commonly known as electronic travel aid. Many of these travelling aids use either ultrasound or laser beam. One of such devices is the laser cane that is similar to a long cane with built-in laser ranging facilities. But most of the commonly used electronic travelling aids use ultrasound for functioning. These devices use the reflectance property of the high frequency ultrasound and are available in different models such as:
A. Sonic torch
It is battery operated and is about the size of a large electric torch. It is a hand held device and operates on the principle of transmitting ultrasound in the forward direction and receiving the reflected beam from a nearby object.
B. Mowat sensor
It is a light weight,'hand held, pocket size device and is quite similar to a common torch that is used by the sighted people. It can detect object by sending high frequency ultrasound in pulses and receiving the reflected beam from any nearby object. User can identify the distance of the object by the rate of vibration that is produced by the device.
C. Sonic pathfinder
Like a Mowat sensor a sonic pathfinders also identify an object by receiving the reflected ultrasound that is emitted by the device. But unlike Mowat sensor which is a hand held device a sonic pathfinder is to be fitted on the head of the user. The audio output from the sonic pathfinder is made up of notes of a musical scale which produce a familiar tonal progression as the user approaches an object, is fed to the user through earphones.
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