'Urgent Help Nedded' Please Please

Discussion in 'The Projects Forum' started by vivek1925, Jul 7, 2010.

  1. vivek1925

    Thread Starter New Member

    May 12, 2010
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    A description of the project :

    This is a walking blind stick that needs to be constructed using a 40 kHz transducer, both transmitter and a receiver. The main aim of the project is to turn on an LED when the stick is 20cm away from the obstacle. The circuit must generate a 40 kHz pulse that should be transmitted with the help of a transducer and a receiver that should receive this signal and turn on an LED indicating a signal is received.
    It is essential to have a circuit diagram and detailed explanation of how these two circuits’ transmitter and receiver and all the explanation of values and components that are used to build this circuit.

    Please comment if u have any ideas with the circuit and what might be the components that should be used.

    Regards
     
  2. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    I assume the LED is to provide warning to the blind person using the stick, right?

    Is this homework?

    John
     
  3. retched

    AAC Fanatic!

    Dec 5, 2009
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    thats funny. lol. I think that is for the teacher to see that its working. ;)

    OP:

    Do some research on proximity sensors and range finders.

    This should give you plenty of designs to study, as well as literature on the hows and whys.
     
  4. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    Don't forget, you will need a degree of directionality and control. You probably don't want to detect the ground, guide dog, or the user's leg as obstacles.

    John
     
  5. retched

    AAC Fanatic!

    Dec 5, 2009
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    That brings up a good point and a question.

    How far does the average blind person hold their walking/seeing sticks tip above the ground?

    In order to set the angle for the directionality, you need to know that, and their height, and the average angle they use the stick.
     
  6. vivek1925

    Thread Starter New Member

    May 12, 2010
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    Actually this circuit should not have any digital components like a range finder that should be programmed with a microchip. That is why we used 555 timer to actually generate a 40KHz pulse but is there any other way in order to generate a pulse.?

    I have attached the transmitter circuit please check. This is the circuit I previously used but was not giving the sufficient outcome.

    Hey retched: The distance from ground should be 30cm
     
  7. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    Please define obstacle.

    My immediate impression was something like a wall or chair. Will ultrasound at 40KHz detect a chair leg reliably? On further thought, I suspect a sharp drop off (like a curb or cliff) might be more of a hazard than a wall or chair with respect to causing injury, particularly if the cane is maintained at least 30 cm above the ground. Thus, such absences of good footing could be consider obstacles to independent mobility. Do you need to detect the absence of solid footing? What about trip risks, which can be considerably less than 30 cm high?

    John
     
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