4. Main Report

8/3/2019 4. Main Report

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Ultracane: Technology Inspired by Nature | Jaimin Patel 1

Echolation

Echolation is recognized as a method utilized by a variety of aquatic, nocturnal, and cave-

dwelling zoological subjects to localize objects and perceive the environment by means ofreflection of ultrasonic sounds, where sound pulses are emitted by the auditory system and

reflected from objects in the environment as waves, which may be interpreted by the auditory

system, similar to the visual system.

The process was termed, "echolocation" by Donald Griffin, who pioneered a breakthrough in

studies of the auditory system upon discovering the use of ultrasonic by bats in order to avoid

obstacles, although echolocation used by bats was observed in the early 19th

century by

Lazzaro Spallanzani, an Italian scientist.

The use of echolocation provides for an increase in independence from strict use of the visual

system, aiding in navigation, orientation, and location of prey in poor light or the dark.

Species to use echolocation include bats and dolphins, primarily, but not exclusively, as

birds, rodents, insectivores, Megachiroptera, fish, seals, cetaceans, large aquatic mammals,

the platypus, and blind humans have been found to use echolocation.


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Animal Echolocation

Animal Echolocation makes use of active sonar, using sounds made by an animal. Ranging

is done by measuring the time delay between the animal's own sound emission and anyechoes that return from the environment. The relative intensity of sound received at each ear

provides information about the horizontal angle (azimuth) from which the reflected sound

waves arrive. Unlike some sonar that relies on an extremely narrow beam to localize a target,

animal echolocation relies on multiple receivers. Echolocating animals have two ears

positioned slightly apart. The echoes returning to the two ears arrive at different times and at

different loudness levels, depending on the position of the object generating the echoes. The

time and loudness differences are used by the animals to perceive distance and direction.

With echolocation, the bat or other animal can see not only where it is going but also how big

another animal is, what kind of animal it is, and other features.

[Cacaphony of Dolphins ... Spectrogram of their Clicks,Whistles, and whines]

[Spectrogram of Pipistrellus Bat as it closes in on prey]


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Echolocation in Bats

Bats are also known specifically for their use of echolocation to navigate and catch prey in

the darkness: they are constantly releasing ultrasonic waves during the whole time they areawake, using it to enhance their sight, which exceeds the sight ofhomo sapiens on its own.

By emitting and receiving ultrasonic sound waves, they retain the ability to see further

distances than many other organisms and can derive information which is much more refined.

Bat sonar process: ultrasonic waves are emitted from the bat as cries which then travel and

are reflected back to the bat upon interacting with a moving or non-moving object of varied

density. By measuring the delay in time from the wave emission and the return of the echo,

the bat is able to determine the distance of the object, where amplitude is used as an

indication of the size and shape of the object. With that information, the bat is able to locate

precisely its prey with knowledge of how large or small it is, and thus it is able to hunt for itsprey.

The sound waves emitted may be of varying frequencies, varying by species and individual,

and different sound waves used may collect more refined information. It has also been found

that the production of ultrasonic cries demands from the bat a large amount of energy,

particularly if the bat is flying, which would suggest that the hunt for food is an exhausting

activity. However, it has been found that to bypass the affects of participating in the two

activities at once, bats who use sonar inhale oxygen to use their flight muscles and exhale air

pulses in order for the ultrasonic waves to be transmitted.

Bats possess a mechanism called automatic gain control (AGC), which provides the bat with

the perception of a fixed echo intensity level as it approaches its target: where echoes will

change based on the change in distance and echo strength, contractions of muscles in the

bats middle ear diminishes after ultrasound emission, which produces changes in the bats

hearing and balances the echo changes due to distance. Amplitude would also change as the

bat moves; however, it is believed that the AGC regulates the amplitude as well.


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Human Echolocation

Human echolocation is the ability of humans to detect objects in their environment by

sensing echoes from those objects. This ability is used by some blind people to navigatewithin their environment. They actively create sounds, such as by tapping their canes, lightly

stomping their foot or by making clicking noises with their mouths. It can however also be

fed in to the human nervous system as a new sensory experience. Human echolocation is

similar in principle to active sonar and to the animal echolocation employed by some

animals, including bats and dolphins.

By interpreting the sound waves reflected by nearby objects, a person trained to navigate by

echolocation can accurately identify the location and sometimes size of nearby objects and

not only use this information to steer around obstacles and travel from place to place, but also

detect small movements relative to objects.

However, in the case of human clicking, since humans make sounds with much lower

frequencies and slower rates, such human echolocation can only picture comparatively much

larger objects than other echolocating animals.

To demonstrate the processes of deriving this conclusion, conceived from bat research, see

the timeline below:

1739: Diderot observed that a blind person could perceive presence and distance of objects.

Theories accumulated to explain this detection: skin sensitivity to temp/pressure; pressure on

tympanic membrane (vibrates sound waves in inner ear); magnetism, electricity, "sixth

sense".

1893: Dresslar experiments on detection of echoes reflected from obstacle surfaces:

eliminated different senses of blindfolded subjects and observed. 1st

condition: vision

eliminated. 2nd

: vision, thermal, and facial pressure eliminated by covering exposed skin but

not auditory meatus. Final: hearing eliminated by plugging ears but leaving face exposed,

eyes covered. It was concluded there was the ability to detect due to some auditory

mechanism but others disagreed with the results.

1941: Griffin, Galambos: 1941 gaggedbats to prevent emission of supersonic cries; plugged

ears to prevent echo reception to show the increase in collision frequency.

Cotzin, Dallenbach: after showing importance of hearing, found that in order for the blind to

avoid collisions with a wall, must hear changes in sound pitch with frequency above 10kHz.

(Higher frequencies allow better echo resolution reflected from small targets)

1944: Supa, Cotzin, Dallenbach: discovered stimulation of auditory system (not skin) was

necessary and sufficient to detect objects. When air-waves prevented from impinging on

exposed skin of blind/blindfolded, the subject could still detect obstacles by listening tofootsteps. When hearing was eliminated and skin left exposed, objects could not be detected.


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1947: Worchel, Dallenbach: found partially deaf and blind could not detect obstacles if

hearing was prevented. If skin of external ears covered but auditory meatus exposed,

obstacles could be detected. Therefore, auditory stimulation was the mechanism used to

detect obstacles in blind.

1953: Ammons, Worchel, Dallenbach: blindfolded subjects able to detect obstacles outdoors,revealing that subjects relied on/sought out non-auditory clues like odors and shadows- other

senses enhance obstacle detection

1962: Kellogg: blind subjects presented with two flat disks of same diameter. For each trial: a

pair of targets, where one was at constant distance with the comparison at variable distance.

Targets presented one after another in a pair in rapid succession. Subjects were to generate

any sound desired (acoustic signals: tongue clicks, hisses, whistles, voice, the latter which

was preferred by subject). Target size kept constant as distance changed: subject was to

report larger of targets by listening to echoes reflected off disks. Kellogg observed that

objects closer to observer thought to be larger than standard of same diameter, where objectsfurther away were perceived as smaller.

The blind have an ability to discriminate objects of different size, with up to 100% accuracy,

the smaller object of two different sized objects (placed at same distance). Performance

decreased as distance increased.

1965: Rice: percent correct detection was proportional to size and distance of object from

observer. At greater distance, objects needed to be larger to be detected. As object was placed

further, sound intensity of echo lowered and object detection became more difficult. As

object size increased, detection improved. Therefore sound intensity of echoes (size and

distance manipulated) affected ability to detect.


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Ultracane

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, actingas 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 objects and reflects back to transmitters 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.


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The alarm can be triggered using different techniques:

1. Beep Alert

A very simple electronic circuit is used for this purpose. The number of beeps for a specifictime period varies directly with the intensity of the sensed signal. If the object is closer, the

number of beeps is higher.

Advantages of beep alert:

Cost effective

Audible alert so easily sensible by the user, a very effective alert system

2. Vibrator Alert

Vibrator alert is employed for users who are both blind and deaf. It not only provides the user

with the comfort of a noise free alert system, but also facilitates use in a noisy environment.

The UltraCanes handle emits ultrasonic waves that bounce off objects as far as four meters

away and send signals to the user through two vibrating buttons on the handle. The strength

of the buttons pulses indicates the direction, height and distance of the objects. The same

part of the brain that a bat uses to orient its movementsthe superior colliculushelps a

human process the buttons pulses to build a spatial map in her minds eye of how the

obstacles are arranged, allowing her to walk more quickly and confidently than she could

with an ordinary white cane.

3. Speech Processor Chip

Speech processor chip can be incorporated with

the current Ultrasound system and recorded

voice alerts can be given to the users. It can be

very instrumental in cases where the direction

of the alert has to be provided. However, one

major drawback of this system is that the user

has to wear an earphone, which interrupts the

sounds from the surrounding environment. Thiswould actually worsen the mobility of the

visually challenged.


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Alternative Aids or Future Advancements

Development of an ultrasound head band for alerting the patient about theobstacles ahead

Smart goggles

Advanced systems based on radar principles

Smart wheel chair

Other Uses of Ultrasound or Similar Principles

SONAR: (SOund Navigation And Ranging)Warfare Civilian Scientific

Anti-submarine warfare Fisheries Biomass estimation

Torpedoes Echo sounding Wave measurement

Mines Net location Water velocity measurement

Mine countermeasures Ship velocity measurement Bottom type assessment

Submarine navigation Remotely Operated Vehicles

(ROV) and Unmanned

Underwater Vehicles (UUV)

Bottom topography

measurement

Aircraft Vehicle location Sub-bottom profiling

Underwater communications Synthetic aperture sonarOcean surveillance Parametric sonar

Underwater security

Hand-held sonar

Intercept sonar

RADAR: (RAdio Detection And Ranging)To identify the range, altitude, direction,

or speed of both moving and fixed objects such as aircraft, ships, spacecraft, guided

missiles, motor vehicles, weather formations, and terrain.

SONOGRAPHY: Medical Imaging: A-scan, B-scan, M-scan, Colour Doppler, etc.

Short Conclusion

Most common solution of our huge problems is lying in nature surrounding us. All

we need to explore ourselves to get it. We cant get human vision, and then at least

try our technology to provide sound as sight. We cant bring evolution at instance

but we can try to make out necessary adjustment to evolve....


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Date post:	06-Apr-2018
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