10-02-2012, 12:36 PM
Ultrasound Usage in Mobility Aid Systems
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The mobility aid system works on the simple principle of reflection of sound waves from the obstacle or an object. For this set up, the system has a simple battery operated circuit, acting as an oscillator producing the required 40 KHz frequency for the operation of the ultrasound generator. The ultrasound generator generates sound waves, which are higher in frequency than the human audible range [ultrasound waves]. Thus generated, sound waves burst open from an optimal point in the walking stick so that the ultrasound could cover the maximum distance. The ultrasound generator is fixed inside a non-foldable walking stick and only the transmitter is exposed to the outer world.
The transmitted sound waves spread and are transported widely in the area around. They travel free in the free surface. During this time, the receiver senses lower than the frequency threshold set by the user. In case of an obstacle ahead, the sound wave gets reflected from the obstacle or object and reflects back to transmitter’s direction.
In the walking stick, the receiver or the sensor is kept very close to the transmitter. The sensor senses the sound waves and if the threshold is exceeded, it amplifies that signal given to the alarm circuit depending on the closeness of the cane to the object. Closer the object higher is the intensity of the alarm
