Vehicle Safety Modifications

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Vehicle Safety Modifications Design Review
Presentation May06-21 Client Senior
design Faculty Advisor Dr. Gary Tuttle Team
Members Joshua Bruening EE Mei-Ling Liew
EE Fei Liu EE Brian Phillips
CprE Adams Sutanto EE December 8, 2005
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Blind Spots

• Driver vision can be restricted by vehicle
  architecture, mirror image resolution, the
  driver's field of vision, and the driver's
  personal mobility, thereby creating blind spots.
• Vehicle structure and visibility constraints are
  two factors that create blind spots and cause
  lane change accidents.

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Common Mirrors

• Adjusting mirrors correctly
• Minimizing the blind-spots not eliminating

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Blind-spot Eliminators

• Improved the drivers view of what is in front
  of, to the side of, and behind the vehicle
• Eliminated the potential danger for accidents
  when entering freeways and backing up
• Solved lane-changing problem

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Blind-spot Eliminators

• The blind-spot mirror is an angled add-on mirror
  that attaches to an existing side mirror to
  increase the blind spot visibility range by 75
  without distortion.

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Technology A

• Driver presses a button
• The exterior mirror moves slightly outward,
  reflecting the blind spot
• Releases the button, and the mirror returns to
  its standard field-of-view.
• Simple and safe

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Technology B

• A red LED directional arrow into the mirror
  glass.
• Additional warning to traffic when the driver
  wants to make lane change.
• Not a distraction when driving at night.

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Technology B

• Drivers are not subjected to the full brightness
  of the LED technology.

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Technology C

• Two digital cameras and advanced computer
  software
• When another vehicle enters the zone an area of
  9.5 meters by 3.0 meters a yellow warning light
  comes on beside the appropriate door mirror in
  the driver's peripheral view

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Technology C

• The system will not function in conditions of
  poor visibility, for instance in fog or flying
  snow
• Too expensive

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Technology D

• A single radar sensor on each side of the vehicle
  continuously scans the adjacent lane of traffic
  from the rear view mirror to about one or more
  car length behind the rear bumper.
• Drivers are notified of potential risks by a
  lighted icon warning light in the outside
  rear-view mirror and can be augmented by an audio
  tone inside the vehicle, at the driver's option.

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Technology E

• The easy-to-apply lens is 6 "x 8" and designed
  for the inside of the back window on SUVs, VANs
  and MiniVANS, Station Wagons and Trucks with
  rear-windowed shells. Made of optical grade PVC
  (polyvinyl Chloride), it can be peeled off and
  re-applied at your discretion.
• The lens is made from a clear, flexible PVC
  material. The lens is soft and may be damaged and
  discolored by harsh cleansers.

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A driver's blind spot is that corner of where
your peripheral vision is cut off and your rear
view mirror does not spread wide enough to see.
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Diagram showing the angle of incidence (i) and
angle of reflection (r).
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Car manufacturers are required to provide flat,
unit magnification mirrors on the driver's side
of the car. Even the inside rear-view mirror
also is flat and shows objects without distortion.
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• Engineers have found out that the convex
  side-view mirror on passenger-side affords
  drivers a
• much clearer view of the passenger-side of the
  car. This is because of the advantage of convex
• mirrors - they allow a much wider angle of
  vision.
• The average radius of curvature not be less than
  35" and no greater than 65".

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The blind spot eliminator will be a simple 3 inch
x 3 inch convex panel mirror added directly on
top of the preexisting side view mirror. The
mirror will be paced so that the angle of
incidence is set to pick up objects picked up by
the original mirror as well as objects in the
preexisting blind spot. The final product will
look similar to the figure below.
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• Other sensor types considered
• Infrared - They can be affected by humidity and
  water, they can be expensive and dust and dirt
  can coat the optics and impair response. We
  want sensors that can operate in all weather.
• 2. Inductive proximity They are ideal for
  virtually all metal sensing applications,
  including detecting all metals or non-ferrous
  metals only. We want to detect any type of
  object.
• 3. Capacitive proximity These are used to
  detect change in the environment rather than to
  detect the absolute presence or absence of an
  object. They do not give a direct indication of
  how far away the detected object is.
• 4. Magnetoresistive These are the type of
  sensors found in a metal detector. We want to
  detect any type of object.

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Fundamental Ultrasonic Properties

• Ultrasonic sound is a vibration at a frequency
  above the range of human hearing, usually gt20
  kHz. The microphones and loudspeakers used to
  receive and transmit the ultrasonic sound are
  called transducers.
• Most ultrasonic sensors use a single transducer
  to both transmit the sound pulse and receive the
  reflected echo, typically operating at
  frequencies between 40 kHz and 250 kHz.
• A variety of different types of transducers are
  used in these systems.

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Choosing an Ultrasonic Sensor for Proximity or
Distance Measurement

•   Variation in the speed of sound as a function
  of both temperature and the composition of the
  transmission medium, usually air, and how these
  variations affect sensor measurement accuracy and
  resolution
•    Variation in the wavelength of sound as a
  function of both sound speed and frequency, and
  how this affects the resolution, accuracy,
  minimum target size, and the minimum and maximum
  target distances of an ultrasonic sensor
•    Variation in the attenuation of sound as a
  function of both frequency and humidity, and how
  this affects the maximum target distance for an
  ultrasonic sensor in air
•    Variation of the amplitude of background
  noise as a function of frequency, and how this
  affects the maximum target distance and minimum
  target size for an ultrasonic sensor
•    Variation in the sound radiation pattern
  (beam angle) of both the ultrasonic transducer
  and the complete sensor system, and how this
  affects the maximum target distance and helps
  eliminate extraneous targets
•    Variation in the amplitude of the return echo
  as a function of the target distance, geometry,
  surface, and size, and how this affects the
  maximum target distance attainable with an
  ultrasonic sensor

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Background Noise

• The level of background ultrasonic noise
  diminishes as the frequency increases.
• The reason is that less noise at the higher
  frequencies is produced in the environment, and
  the noise that is produced is greatly attenuated
  as it travels through the air.

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Target Range Measurement

• For each application, it is important to select a
  sensor that will detect the desired targets when
  they are located within a specified area in front
  of the sensor, but ignore all targets outside
  this area.
• A lower frequency sensor should be selected for
  longer ranges of detection and a higher frequency
  sensor should be used for shorter range, higher
  resolution measurements.
• Sensor beam angles should be selected to cover
  the desired detection geometry, and to reject
  unwanted targets.

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The major benefit of ultrasonic sensors is their
ability to measure difficult targets such as
solids, liquids, powders and even transparent and
highly reflective material.
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Limitations

• Ultrasonic devices do have some limitations. Foam
  and other attenuating surfaces may absorb most of
  the sound, significantly decreasing measuring
  range.
• Extremely rough surfaces may diffuse the sound
  excessively, decreasing range and resolution.
  However, an optimal resolution is usually
  guaranteed up to a surface roughness of 0.2 mm.
• Ultrasonic sensors emit a wide sonic cone,
  limiting their usefulness for small target
  measurement and increasing the chance of
  receiving feedback from interfering objects.
• Some ultrasonic devices offer a sonic cone angle
  as narrow as 6º, permitting detection of much
  smaller objects and sensing of targets through
  narrow spaces such as bottle necks, pipes, and
  ampoules

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Ultrasonic sensors

• A picture of two ultrasonic sensors is shown
  below
• Two sensors work in unison, one as the
  transmitter and one as the receiver.  The
  transmitter typically sends out a constant beam
  of sound at a frequency of 40KHz (note that the
  human hearing barely goes above 17KHz). 
• The receiver detects any sounds coming in and
  gives us a voltage out.  So, what happens is the
  transmitter sends out a signal.  If there isn't
  an object in front of it, then the sound wave
  will carry on (note there is a limit to the
  distance here!).  If, and only if, there is an
  object in the way, the sound waves will bounce
  back along the same path, and so be picked up by
  our receiver