This presentation can be used as the introduction for a unit on building the YourDuino Basic Robot Kit. (http://www.yourduino.com/sunshop/index.php?l=product_detail&p=400)

1. Ultrasonic Distance Sensor
Nature and the Science behind an
ingenious device

2. There are many things that travel through
the air in waves. Some we cannot see.

3. Light & Sound
• You can see a flash of Lightning almost instantly
• But it takes a while before you hear the thunder
• You can count to tell how far away it is
• Sound takes about 5 seconds to go 1 mile

4. Sound Waves

5. What can they hear?
• Humans – up to 20,000 Hz
• Dogs – up to 40,000 Hz
• Cats – up to 60,000 Hz
• Bats – up to 100,000 Hz
• Dolphins – up to 150,000 Hz

6. Forms of Sound Waves
Human

7. What are Echoes?

8. What is Echolocation ?
"Echolocation is the use of sound waves
and echoes to determine where objects
are in space”
In other words, echoes help to find the
location of an object.
http://askabiologist.asu.edu/echolocation

9. Bats Use Echolocation

10. http://askabiologist.asu.edu/sites/default/files/echolocation.jpg
• Bats send out sound waves using their mouth or nose.
• When the sound hits an object, an echo comes back.
• The bat can identify an object by the sound of the echo.

12. Blind as a Bat?
• Most bats eat flying insects.
• Bats can see as well as humans, but
echolocation is much more important to
them than their eyesight for finding food.
• Bat’s Echolocation is so precise that it can
detect an object the width of a human hair.
• Mother bats who are feeding their babies,
may catch and eat up to 4500 insects in one
night!

13. Bats can even tell the size, shape and texture of
a tiny insect from its echo .

14. Some moths have developed ways to get away or confuse
bats, such as:
• Furry wings that don't reflect bat echolocation
pulses.
• Sensitive membranes that can 'hear' echolocation
pulses. When the pulses are detected, the moths fly
in crazy patterns or fold their wings and dive to
confuse their hunters.
http://academic.reed.edu/biology/professors/srenn/pages/teaching/web_2007/pf_site/adaptation.html

15. Books you might enjoy!

16. Ultrasound is too high a
Pitch for Humans to Hear

17. The Tiger Moth

18. • The Tiger Moth Can can emit
ultrasonic clicks to "jam" a Bat's sonar
(SOund Navigation And Ranging)
• By producing ultrasound of its own, it
is able to ward off bats by acting as a
radar jammer, confusing the bats so
that the moth cannot be located.
http://en.wikipedia.org/wiki/Arctiidae

19. Philippine Tarsier

20. A Scientist was puzzled because she could
hear no sound when Philippine Tarsiers
opened their mouths as if to call.
She placed a Tarsier in front of an ultrasound
detector. It revealed that what she had
assumed to be yawns were high-pitched
screams beyond the range of human hearing.
The Tarsier, only 4 inches long,
communicates using ultrasound at 70 KHz.

21. Read more about Tarsiers!

22. Dolphin

23. The Dolphin uses nasal passages to make clicking sounds,
sending them through its forehead, which focuses the sounds
together into a beam before sending it into the water.

24. • When the sound hits an object in the water, it bounces
back to the dolphin as an echo.
• The dolphin absorbs this returning echo through its jaw.
• A passage of fat from the jaw conducts the sound to the
dolphin's inner ear
• The dolphin can tell things about the object, such as size,
shape and material.

25. The cricket, Arachnoscelis lives in the tropical rain forests,
and can produce the highest-frequency ultrasound of any
known insect. These sounds are emitted by the lonely
male, which makes its presence known with a burst of
intense sounds. Listen to their calls!
http://www.sci-news.com/biology/science-bushcricket-
colombia-01265.html

26. House mice use Ultrasonic sounds to attract mates.
Rats and other rodents also use it to communicate.

27. The Huia Cavitympanum is the only known frog species
that can communicate using purely ultrasonic calls. This
unusual frog lives in the Philippines. These frogs can hear
sounds up to 38 kilohertz, the highest frequency any
amphibian species has been known to hear.

28. Science Technology Engineering
• Scientists look at Nature and try to
explain it
• Engineers figure out how to make Science
useful using Technology
• Engineers build new things using
Technology

29. Humans cannot create or hear ultrasound, by
themselves, but we can make devices that do this
for us.
How Is Echolocation used by humans?

30. How it works:
1. A chirp is emitted from the “speaker”
2. It bounces off of an object
3. The echo returns to the microphone
4. The time it takes to travel to the object and back is used to figure out the distance

31. Some Uses of
Ultrasound & Ultrasonic Distance Sensors

32. Ultrasound Drives Mice Crazy!

35. Robots

36. Driverless Cars
Google Driverless Car

37. http://www.economist.com/node/21560989

39. http://wbbw1.bwbx.io/cms/2012-04-09/0409_GigaOM_car_630x420.jpg

40. http://america.aljazeera.com/watch/shows/techknow/blog/2013/10/24/-techknow-need-toknow6questionsyoushouldaskaboutdriverlesscars.html

41. The Tactic Device for the Blind

42. How the Tactic Works

43. • The Tactic can help the blind move around
safely.
• It is mounted on your wrist and uses ultrasonic
sensors set above the knuckles that can pick up
the distance of objects from one inch to 10 feet
away
• It then translates that distance to pressure on
the wrist--the closer the object, the more
pressure on the wrist.
Read more at: http://phys.org/news/2011-09-tacit-device-safety-video.html#jCp

44. The Hand Bat

45. • The Hand Bat is a simple Do It Yourself (DIY)
device similar to the Tactic
• It uses an Arduino Microcomputer, an
ultrasonic sensor and a beeper
• It is built in a low-cost waterproof flashlight
case
• When you point it in different directions, it
sends out an ultrasonic sound and listens for
the echo
• It figures out the distance and tells the user
how far away an object is with different sounds

46. Read More!