what kind of sensor should i use?

Discussion in 'Homework Help' started by zubir, Jan 14, 2010.

  1. zubir

    Thread Starter New Member

    Jan 12, 2010
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    im doing my final year project and im building an automatic car braking system...
    :confused:
    what kind of sensor should i use to detect the gap with the front car. the min distance will be 6m. is it possible for the sensor to detect from 6m then 3m n lastly at 1m, then it transmit the data to PIC ?
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
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    What would be the advantages of:

    1. Light

    2. Sound

    3. Video object recognition

    4. RF

    If there is a minimum distance, what is the maximum? What will the data look like?
     
  3. zubir

    Thread Starter New Member

    Jan 12, 2010
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    the max range will be around 100m if possible...

    i have done some research, i found out that i can use Laser Range Finders or Proximity Sensor...is it practical to use and how much is the price range?
    my budget for the sensor is around $70...is it possible?

    does infrared sensor can go up to 100m?? what is ur opinion about ultrasonic sensor??
     
  4. retched

    AAC Fanatic!

    Dec 5, 2009
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    What is your project budget? I know you said you have a $70 sensor budget but what about the rest?

    here is a sensor from .2m to 100m using laser:
    latronix.org/pdf/andras_matare/MEL/M10.pdf
     
    Last edited: Jan 16, 2010
  5. retched

    AAC Fanatic!

    Dec 5, 2009
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    Ultrasonic sensors maximums are usually measured in inches. Unless you want something really big, i.e. 14-18inches across, which is really expensive and power hungry. For the under $100 range I would be surprised to see one that can sense over 10 feet.

    Infrared is also a short distance sensor. And using it outdoors can give you erratic results. The sun can cause false positives for your breaking system. Imagine driving at highway speeds when a glare from the sun tells the sensor that there is a car 2 inches in front of you. Slamming on the breaks at high speeds with no warning can cause serious and fatal results.

    Laser ranging is probably the way you should go. Or radar. Do you require the 100m distance? It seems 330 feet is really far for this application. But you know what you want.
     
    Last edited: Jan 16, 2010
  6. beenthere

    Retired Moderator

    Apr 20, 2004
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    Think of optical devices in muddy conditions or snowy. RF is about it.

    The 100 m is reasonable. At 60 MPH, the distance traveled is 88 FPS.
     
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